Parrott - Overview


Professor Andy Parrott is an international authority on the human psychobiology of MDMA or Ecstasy. He has published numerous research papers on its recreational use, including the first to demonstrate memory impairments in young Ecstasy/MDMA users compared to similar aged controls. These research findings have been presented at numerous conferences in the UK and mainland Europe, Australia, Canada, and USA. He has been invited to present research seminars at many universities, including Yale and Harvard. He has written a number of widely-cited review articles, organized several   international symposia, and edited various academic journals dedicated to Ecstasy/MDMA research.


Professor Andy Parrott’s other main field of research expertise is the psychobiology of  nicotine dependency. In an extensive research program, he has shown how cigarette smoking causes increased stress and depression. Furthermore the explanatory model of nicotine dependency which he has proposed, explains why cigarette smoking can generate so many psychological problems in smokers. These findings have been presented in numerous journal articles and conference papers.


In total, he has over 300 journal articles, book chapters, and conference papers. They cover the main classes of psychoactive drug, including CNS stimulants such as amphetamine, CNS depressants such as alcohol and benzodiazepines, antipsychotic drugs for schizophrenia, antidepressants, cognitive enhancers, anabolic steroids, and recreational drugs such as cannabis, LSD and ketamine. He has also written a leading European textbook on this area, published by John Wiley, entitled: ‘Understanding Drugs and Behaviour’, with co-authors Andy Scholey, Alun Morinan, and Mark Moss.


The research papers are presented in the following groups


  • MDMA reviews
  • Memory and Cognition in Ecstasy/MDMA users
  • Self-reports by recreational Ecstasy/MDMA users
  • Psychiatric distress in recreational Ecstasy polydrug users
  • Ecstasy/MDMA use in dance clubs
  • Ecstasy/MDMA conferences and symposia

Cigarette smoking and nicotine dependency.

  • Nicotine dependency: psychobiological problems caused by cigarette smoking
  • Cigarette use and psychobiological vacillation over the day
  • Cognitive skills of smokers and Nesbitt’s Paradox
  • Nicotine withdrawal, nicotine gum, and smoking cessation

Other psychoactive drugs.

  • Many drugs listed

Visual Aesthetics.

  • Just a few visual aesthetics papers


Copyright for all the articles is owned by the various journal publishers.

The PDF files are attached to this webpage through various permissions and journal subscriptions by Swansea University.

Thanks in particular to: Springer-Verlag (Psychopharmacology), Sage (Journal of Psychopharmacology), Wiley (Human Psychopharmacology), and many other publishers (other journals)


MDMA reviews



The first Ecstasy/MDMA review article in Neuropsychobiology was published in 2000, and was based on the first Novartis Foundation symposium meeting.

The second review in 2001 was a more comprehensive review, which attempted to cover human MDMA research from the very first studies 15 years earlier. It presents a broad overview of the area, and remains in the top ten list of cited articles from the journal Human Psychopharmacology.

The 2002 article covered the serotonin syndrome, and was the second most highly cited paper for the journal Pharmacology Biochemistry, and Behaviour, that year.

The 2004 paper in Psychopharmacology examines the question of whether Ecstasy tablets contain MDMA.

The 2005 Journal of Psychopharmacology article on chronic tolerance, explains why ecstasy users often increase their dosage, yet find it less effective over time.

The 2006 review in the Journal of Psychopharmacology focused on research between 2001-2005, and integrated the findings into an explanatory model for MDMA based around metabolic stress.

The Editorial & commentary in the Journal of Psychopharmacology discussed the relative psychobiological costs of alcohol, Ecstasy/MDMA, and Aldous Huxley’s euphoriant ‘soma’.

The 2007 paper in Psychopharmacology critically evaluated the proposal that MDMA might be useful as an adjunct for psychotherapy.



Parrott, A.C. (2000).  Human Research on MDMA Neurotoxicity: Cognitive and Behavioural indices of change.  Neuropsychobiology, 42, 17-24. PDF


Turner, J.J.D. & Parrott, A.C. (2000)  The neurotoxicity of MDMA ("Ecstasy") in humans: Viewpoints of the discussants.  Neuropsychobiology, 42, 42-47. PDF


Parrott AC (2001). Human Psychopharmacology of MDMA (Ecstasy): a review of fifteen years of empirical research.  Human Psychopharmacology, 16, 557-577. PDF


Parrott AC (2002). Recreational MDMA (Ecstasy), the serotonin syndrome, and serotonergic neurotoxicity. Pharmacology, Biochemistry and Behavior, 71, 837-844. PDF


Parrott AC (2002)  The long term effects of ecstasy/MDMA are real and

psychobiologically damaging. Note: the title was amended by the journal editors

to:  'Very real, very damaging'. The Psychologist, 15, 472-473. PDF


Parrott AC (2004). Is Ecstasy MDMA ? A review of the proportion of ecstasy tablets containing MDMA, their dosage levels , and the changing perceptions of purity. Psychopharmacology, 173, 234-241. PDF


Parrott AC (2005). Chronic tolerance to recreational MDMA  (3,4-methylenedioxymethamphetamine) or Ecstasy. Journal of  Psychopharmacology, 19, 71-83. PDF


Parrott AC, Marsden C (2006) MDMA (3,4-methylenedioxymethamphetamine) or Ecstasy: the contemporary human and animal research perspective. Journal of Psychopharmacology 20: 143-146.  PDF


Parrott AC (2006). MDMA in humans: factors which influence the neuropsychobiological profiles of recreational Ecstasy users, the integrative role of bio-energetic stress. Journal of Psychopharmacology 20: 147-163 PDF


Parrott AC (2007). Ecstasy versus alcohol: Tolstoy and the variations in unhappiness. Journal of Psychopharmacology 21: 3-6.  PDF      

(commentary on an earlier JoP Editorial by Nutt DM PDF ).


Parrott AC (2007). Alcohol, ecstasy, Aldous Huxley’s ‘soma’. Journal of Psychopharmacology 21: 8-9. PDF 

(also see David Nutt’s reply PDF ).


Parrott AC (2007). The psychotherapeutic potential of MDMA (3,4-methylendioxymethapmphetamine): an evidence based review. Psychopharmacology 191: 181-194. PDF






Memory and cognition in Ecstasy/MDMA users.


In one of our earliest studies, we administered the Cognitive Drug Research test battery to abstinent Ecstasy/MDMA users and nonuser controls.  On most tasks the groups were very similar, but on immediate and delayed word recall, the Ecstasy users were significantly impaired. There was a prior clinical report from America of memory problems in some heavy users of Ecstasy, but this was the first empirical demonstration of cognitive/memory impairments in Ecstasy users compared to controls. Professor Andy Parrott and his team of co-workers (Alex Lees, Dr. Miranda Jones, Natasha Garnham, and Professor Keith Wesnes of CDR), were awarded a prize from British Association for Psychopharmacology for their 1998 journal paper.


This initial report of memory deficits was confirmed in a follow-up study undertaken by Joanna Lasky. This Psychopharmacology article remains one of their most highly cited papers. In a series of further investigations, Professor Parrott’s group at the University of East London (UEL), where he was then based, investigated the nature of these cognitive/memory changes in more detail. The studies involved a wide variety of cognitive tasks, covering skills such as executive planning, visual vigilance, psychomotor integrity, and different aspects of memory. This programme was co-led by Dr. John Turner, research collaborator and Senior Lecturer at UEL. Their first postgraduate research student in this area, Helen Fox, undertook a number of ground-breaking studies. Helen compared regular Ecstasy users who complained of drug-related problems, with an equivalent group of Ecstasy users who did not complain of any drug-related problem. Against predictions, the cognitive/memory scores for these two groups were very similar. Memory deficits were evident, but these were related to the amount of Ecstasy taken, irrespective of whether the individual complained of problems. Helen and her supervisors (AP and JT) were awarded the BAP prize in 2002 for the resulting Journal of Psychopharmacology paper.  Helen then established links with Barbara Sahakian's Neuropsychology Group at Cambridge University. She administered the Neuropsychological Test Battery (CANTAB) heavy Ecstasy users and controls, in assess whether their overall cognitive profiles matched those of any of Sahakian’s neurosurgery patient groups. Her data suggested a very close match with temporal lobe and amygdalo-hippocampal patients. Following her PhD, Helen was appointed as postdoctoral researcher at Yale University, where she has been investigating the psychobiology of cocaine.


At Swansea University, the effects of MDMA have been compared with those of cannabis. Some of the review papers have involved close collaboration with Professor Efi Gouzoulis-Mayfrank from Koln University in Germany. Other empirical studies have been undertaken as part of Jacqui Rodgers’ www Internet group (listed below in that section). Recently we investigated EEG and memory, in a collaborative study with Professor Adrian Burgess (Swansea webpage). In this pilot study, significant reductions in EEG theta power were evident in the abstinent Ecstasy/MDMA, compared to non-users controls, during the performance of memory tasks. Further EEG studies are currently being planned.


Parrott AC (1996). MDMA, mood and memory: the agnosia of the Ecstasy. Annual Scientific Meeting of the Psychobiology Section of the British Psychological Society, September 1996. British Psychological Society Proceedings (2007), 5, p49.


Parrott AC (1997). Ecstatic but memory depleted ? The Psychologist, 10, 265.


Parrott AC, Lees A, Garnham NJ, Jones M, Wesnes K (1998). Cognitive performance in drug-free recreational Ecstasy (MDMA) users: evidence for memory deficits. Journal of Psychopharmacology, 12, 79-83. PDF


Parrott AC, Lasky J (1998). Ecstasy (MDMA) effects upon mood and cognition: before, during, and after a Saturday night dance. Psychopharmacology, 138, 261-268. PDF


Fox HC, Parrott AC, Turner JJD (2001). Ecstasy use: cognitive deficits related to dosage rather than awareness of problems.  Journal of Psychopharmacology, 15, 273-281. PDF


Fox HC, Toplis AS, Turner JJD, Parrott AC (2001). Auditory verbal learning in drug-free recreational Ecstasy polydrug users. Human Psychopharmacology, 16, 613-618. PDF


Fox HC, McLean A, Turner, JJD, Parrott AC, Rogers R, Sahakian BJ (2002)  Neuropsychological evidence of a relatively selective profile of temporal dysfunction in drug-free MDMA (ecstasy) polydrug users.  Psychopharmacology 162, 203-214. PDF


Fox HC, Turner JJD, Parrott AC  (2003). Prepulse inhibition of acoustic startle in drug free Ecstasy polydrug users.   Adiktologie, 3, 13-19.


Parrott AC, Fox HC, Milani RM (2003). Cannabis, Ecstasy/MDMA, and memory: commentary on Simon and Mattick’s recent study. Addiction 98, 1003-1005. PDF


Parrott AC (2003). Cognitive decline and cognitive normality in recreational cannabis and Ecstasy/MDMA users.  Human Psychopharmacology, 18, 89-90. PDF


Parrott AC, Gouzoulis-Meyfrank E, Rodgers J, Solowij N. (2004). Ecstasy/MDMA and   cannabis: the complexities of their interactive neuropsychobiological effects.  Journal of Psychopharmacology, 18, 575-575. PDF


Parrott AC, Milani RM, Gouzoulis-Meyfrank E, Daumann J. (2007). Cannabis and Ecstasy/MDMA ((3,4-methylenedioxymethamphetamine): an analysis of their neuropsychobiological interactions in recreational users.  Journal of Neural Transmission        PDF





Self-reports by recreational Ecstasy/MDMA users.


In our very first Ecstasy study, undertaken by Darren Davison in 1992-3,  recreational MDMA users were given structured interviews which covered their psychological and physiological experiences, on-drug and off-drug. They also completed a mood adjective checklist to describe their feelings on-Ecstasy. They were followed in subsequent years by a number of further studies, by Malcolm Stuart and others.


In 2000, Dr Jacqui Rodgers from Newcastle University initiated the establishment of a WWW group for memory/cognitive research involving Ecstasy and other drug users. The group comprised Dr. Tom Buchanan (Westminster University), Dr. Jonathan Ling (Keele University), Dr. Brian Tiplady (Astra-Zeneca), Prof. Andy Scholey and Dr. Tom Heffernan (Northumbria University), and Prof. Andy Parrott (Swansea University). The www approach allows very large samples to be assessed. This has allowed us to undertake a number of studies into self-rated memory and cognition, and the influence of dancing/exercise and thermal comfort, on mood states and cognitive integrity.  Fro instance, in 2006, we reported that memory problems were most evident in those clubbers who danced the most while on-drug. Thermal comfort when on-drug were also associated with the extent of psychobiological problems being self-reported.


Parrott AC, Davison D (1995). Profile of mood states of Ecstasy (MDMA) users. Journal of  Psychopharmacology,  9, a48.


Parrott, A.C. (1996) Ecstasy (MDMA): Self-rated mood effects in recreational drug users.  Journal of Psychophysiology, 10, 77.


Davison D, Parrott AC (1997). Ecstasy (MDMA) in recreational users; self-reported psychological and physiological effects. Human Psychopharmacology, 12, 221-226. PDF


Parrott AC, Stuart M (1997).  Ecstasy (MDMA), amphetamine and LSD: comparative mood profiles in recreational polydrug users. Human Psychopharmacology, 12, 501-504. PDF


Rodgers J, Buchanan T, Scholey AB, Heffernan TM, Ling J, Parrott AC (2001). Differential effects of Ecstasy and cannabis on self-reports of memory ability: a web based study.   Human Psychopharmacology, 16, 619-625. PDF


Parrott AC,  Buchanan T, Scholey AB, Heffernan TM, Ling J, Rodgers J (2002). Ecstasy/MDMA attributed problems reported by novice, moderate and heavy users. Human Psychopharmacology, 17, 309-312. PDF


Rodgers J, Buchanan T,  Scholey AB, Heffernan TM, Ling J,  Parrott AC (2003). Patterns of drug use and the influence of gender on self-reports of memory ability in ecstasy users: a web based study. Journal of Psychopharmacology 17, 389-396. PDF


Parrott AC,  Buchanan T, Heffernan TM, Scholey A, Ling J, Rodgers J (2003). Parkinson’s disorder, psychomotor problems, and dopaminergic neurotoxicity in recreational Ecstasy/MDMA users. Psychopharmacology, 167, 449-450.


Scholey AB, Parrott AC, Buchanan T, Heffernan TM, Ling J, Rodgers J         (2004). Increased intensity of Ecstasy and polydrug usage in the more experienced recreational Ecstasy/MDMA users: a WWW study. Addictive Behaviors, 29, 743-752. PDF


Buchanan T, Ali T, Heffernan TM, Ling J, Parrott AC, Rodgers J, Scholey AB (2005). Non equivalence of online and pencil-and-paper tests: the case of the Prospective Memory Questionnaire. Behavioural Methods and Research Instrumentation. 37, 148-154.


Rodgers J, Buchanan T, Pearson C,  Parrott AC, Ling J, Heffernan T, Scholey AB (2006). Differential experiences of the psychobiological sequelae of ecstasy use: quantitative and qualitative data from an internet study. Journal of Psychopharmacology 20: 437-446. PDF



Psychiatric distress in recreational Ecstasy polydrug users.


We have undertaken several studies into the psychological well-being and psychiatric status of young recreational Ecstasy users. Elaine Sisk assessed youngsters from a town in Ireland where recreational drug use was extensive. The heavy Ecstasy user group  reported a wide range of psychiatric symptoms, while the lighter Ecstasy user group was also impaired on some scales. Margherita Milani undertook an extensive investigation of several hundred young people from Rome, Padua, and London, while Rishee Parmar assessed a smaller group from Manchester. Self-rated levels of psychiatric distress were found to be significantly associated with greater polydrug usage (i.e. not just ecstasy). Several types of psychiatric symptom were more prevalent in those who have taken various illicit drugs, with heavy Ecstasy polydrug users often reporting many problems. Positive life experiences were also systematically recorded, but they were not associated with drug usage. Margherita Rafaella Milani is now a full-time lecturer at Thames Valley University, where she is continuing her psychopharmacological research.


Kirstie Soar undertook a series of studies into the clinical well-being of heavy MDMA users, some of whom complained of drug-related problems. Kirstie has also reviewed the literature on clinical case studies. Since award of her PhD, Kirstie has been employed as a full-time Lecturer in the Psychology Department at the University of East London.


Parrott, A.C., Sisk, E., Turner, J.J.D. (2000)  Psychiatric problems in heavy "Ecstasy" (MDMA) Polydrug users.  Drug and Alcohol Dependence, 60, 105-110. PDF


Parrott AC, Milani RM, Parmar R, Turner JJD (2001). Recreational Ecstasy/MDMA and other drug users form the UK and Italy: psychiatric symptoms and psychobiological problems.  Psychopharmacology, 159, 77-82. PDF


Soar K, Turner JJD, Parrott AC (2001). Psychiatric disorders in Ecstasy (MDMA) users: a literature review focusing upon personal predispositions and drug histories.   Human Psychopharmacology, 16, 641-645. PDF


Parrott AC, Milani RM, Turner JJD (2002).  Ecstasy and the SCL-90 findings: a reply to Cole.  Psychopharmacology 162, 218-222. PDF


Milani RM, Parrott AC, Turner JJD, Fox HC  (2004). Gender differences in self-reported anxiety, depression and somatization among ecstasy/MDMA polydrug users, alcohol/tobacco users, and nondrug users. Addictive Behaviors, 29, 965-971. PDF


Soar K, Parrott AC, Fox HC (2004). Persistent neuropsychological problems after seven years of abstinence from recreational Ecstasy (MDMA): a case study. Psychological Reports, 95, 192-196.


Milani RM, Parrott AC, Schifano F, Turner JJD (2005). Patterns of cannabis use in ecstasy polydrug users: moderate cannabis use may compensate for self-rated aggression and somatic symptoms. Human Psychopharmacology 20: 249-261. PDF


Soar K, Turner JJD, Parrott AC (2006). Problematic versus non-problematic Ecstasy/MDMA use: the influence of drug usage patterns and pre-existing psychiatric factors. Journal of Psychopharmacology 20: 417-424. PDF


Parrott AC, Rowe KL, Watts LA, Kissling C, Thome J (2007). Novice versus experienced polydrug users: Psychiatric problems and ADHD symptoms are related to the heaviness of drug usage. Annual Conference of the British Association for Psychopharmacology, Harrogate, July 2007. Journal of Psychopharmacology,




Ecstasy/MDMA use in dance clubs.


In 1997, we tested a group of recreational drug users before they went out dancing/clubbing, at the club following self-administered drug, then 2 days and 7 days afterwards. The aim was to prospectively monitor any changes in self-rated mood states and cognitive skills over time. The moods of the control group, mostly social drinkers, were steady over the week. They reported having a good time at the dance club, and few adverse effects 2 and 7 days later. In contrast the moods of the Ecstasy users fluctuated markedly over time. They reported excellent moods at the club - although not significantly better than controls. Midweek they reported numerous adverse moods, some of which were quite severe. Cognitive skills were assessed on a hand held microcomputer, and significant memory impairments were evident at every session, probably due to their regular use of MDMA.


Following the first study in London, this area of research has been continuing at Swansea. Lucy Young assessed three groups of dance clubbers: Ecstasy/MDMA users, those who had used Ecstasy previously but who had not taken it on that evening, and never-users as the controls. Body temperature and thermal self-ratings were significantly higher in the current Ecstasy users, and were also raised to a lesser extent in the abstinent group.  Adverse mood profiles during the post-MDMA recovery period were also confirmed. Next year Jake Lock undertook the world’s first within-group study of Ecstasy-user dance clubbers on-MDMA, compared to clubbing off-MDMA. This prospective study of MDMA abstinence, involved saliva samples for the determination of MDMA. When clubbing on MDMA, cortisol levels increased by around 800%. This was confirmed in a two later studies.


In another www article with Jacqui Rodgers, we noted how more memory problems were reported by those who danced the most while on MDMA. The close links between Ecstasy and dance clubbing have been debated in two review articles. The 2002 paper outlined how acute doses of MDMA can cause an acute reaction with many parallels with the serotonin syndrome. The 2004 paper debated the psychobiological implications of taking MDMA in hot and crowded conditions, such as those found in dance clubs and raves.  These studies have involved close collaboration with Professor Johannes Thome and Dr. Christian Kissling from the Medical School at Swansea University.


Parrott AC, Lasky J (1998). Ecstasy (MDMA) effects upon mood and cognition: before, during  and after a Saturday night dance. Psychopharmacology, 139, 261-268. PDF


Parrott AC (2004). MDMA (3,4-methylenedioxymethamphetamine) or Ecstasy: the neuropsychobiological implications of taking it at raves. Neuropsychobiology, 50, 329-335. PDF


Parrott AC, Young L (2005). Increased body temperature in recreational  Ecstasy/MDMA users out clubbing and dancing. Journal of Psychopharmacology, 19, a26.


Parrott AC, Rodgers J, Buchanan T, Ling J, Heffernan T, Scholey AB (2006). Dancing hot on Ecstasy: physical activity and thermal comfort ratings are associated with the memory and other psychobiological problems reported by recreational MDMA users. Human Psychopharmacology 21: 285-298. PDF


Lock J, Kissling C, Thome J, Parrott, AC (2006). Cortisol, testosterone and mood changes in Ecstasy-MDMA users at a Saturday night dance club: a brief prospective study.   Journal of Psychopharmacology, 20, a52.


Parrott AC, Burgess A, Edwards RL, Jones H (2007). EEG theta amplitude reduced in cannabis and cannabis-ecstasy polydrug users undertaking a recognition memory task. Journal of Psychopharmacology (in press).


Parrott AC, Adnum L, Evans A, Kissling C, Thome J (2007). Heavy ecstasy-MDMA use at cool house parties: Substantial cortisol release and increased body temperature. Journal of Psychopharmacology (in press).





Ecstasy/MDMA conferences and symposia.


Andy Parrott has proposed, and arranged the programs for, the following Ecstasy/MDMA symposia.


1995.   "Psychoactive Drugs of Use and Abuse" (with Martin Yeomans). British Psychological Society Annual Conference. Warwick University UK.

1997.   "The Psychobiology of Ecstasy or MDMA". British Psychological Society Annual Conference, Herriot-Watt University, Edinburgh.

1998.   "MDMA (Ecstasy): a Human Neurotoxin ?". Novartis Foundation, London.

2001.   "The Neuropsychopharmacology of MDMA (Ecstasy)". Canadian College of Neuropsychopharmacology and British Association for Psychopharmacology Conference, International Conference Centre. Banff Canada.

2004    “Neuropsychiatric and psychobiological aspects of recreational cannabis and ecstasy use”.  International Congress of Biological Psychiatry. Sydney Australia.

2004     “Ecstasy: benign pleasure or potential plague” (with Richard Green and Charles Marsden). British Association for Psychopharmacology Annual Conference, International Conference Centre. Harrogate UK.

2004    “MDMA/Ecstasy: the human and animal research interface”. Novartis Foundation, London.

2006    “Memory and Ecstasy/MDMA”. International Conference on Memory; fourth meeting (ICOM-4). University of New South Wales, Sydney, Australia. .







Nicotine dependency: the psychobiological problems caused by cigarette smoking


The cigarette smoking research is primarily concerned with the adverse effects of nicotine on mood and cognition. Many research groups state that smoking helps with mood control. However in an extensive series of studies, Prof. Andy Parrott has shown the central role of psychobiological vacillation, so that tobacco smoking can actually cause many forms of psychological distress. Cigarette smokers only feel 'normal'  when replete with nicotine, and in-between cigarettes their moods soon deteriorate. The apparent mood gains of smoke inhalation, only represent the temporary return to psychological normality. In between cigarettes, smokers experience increasing levels of psychobiological distress, with frequent cravings. Nicotine dependency therefore directly causes smokers to experience greater moodiness, irritability,  anger and depression each day. This helps to explain why adolescent smokers become more stressed a year after they have taken up smoking. Also why adult smokers are significantly more stressed than adult nonsmokers. Finally, quitting smoking gradually leads to reduced stress - after the immediate post-cessation period of strong cravings has subsided. Nicotine dependency also causes memory problems, so your memory should also improve once you quit.


There are some simple messages for tobacco smokers. Firstly, do not smoke. The tar and carbon monoxide in cigarette smoking will soon damage your heart and lungs. The adverse effects on breathing can be measuring within a few months of taking-up smoking. Your skin will become wrinkly, and impaired blood supply to the penis may lead to impotence. These adverse medical effects may kill you. The probability of a smoker dying from a tobacco-related disease is around 50%. In psychological terms, nicotine dependency will cause you to feel moody, irritable and stressed, each day.


My advice is to quit immediately. Your physical health will start to recover within a few weeks. Over successive months your breathing and health will continue to improve. You will feel much better. Your chances of heart disease and cancer will drop dramatically. The long-term health benefits of cessation are well documented.


What is less well known is that your psychological well-being will also improve after quitting. These mood improvements will take between a few weeks and several months to occur, depending on the severity of your dependency. It will be a gradual process, so you will need to persevere. Initially you may suffer from strong cravings every day, and increased stress for several weeks, but these problems will gradually disappear over time. Once you have permanently quit – you will feel less moody, less irritable, more contented, and less prone to depression.



Parrott AC (1999). Does cigarette smoking cause stress ? American Psychologist, 54, 817-820.


Parrott, A.C. (2000) Cigarette smoking does cause stress.  American Psychologist, 55, 1159-1160.


Parrott, A.C. (2000) Smoking and adverse childhood experiences.  Letter to the Editor: Journal of the American Medical Association, 283.


Parrott, A.C. (2001)  Cigarette smoking/nicotine dependency: A direct cause of stress and depression.  Los Angeles Psychologist, November, 24-26.


Parrott AC (2003). Cigarette-derived nicotine is not a medicine.   World Journal of Biological Psychiatry, 4, 49-55. PDF (note: PDF file covers the whole journal issue, so print pages 49-55).


Parrott AC (2004). Heightened stress and depression follow cigarette smoking. Psychological Reports, 94, 33-34.


Parrott AC (2006). Nicotine psychobiology: how chronic-dose prospective studies can illuminate some of the theoretical issues from acute dose research. Psychopharmacology 184, 567-576. PDF



Cigarette use and psychobiological vacillation over the day.


The original studies which led to the above model, investigated the mood effects of cigarettes smoked over the day. Smokers went about their normal activities, and smoked cigarettes normally. Before each cigarette they complete a brief mood scale to indicate their current feelings of stress, arousal, and pleasure. Then immediately after each cigarette, they complete the same mood scale. This design allowed the effects of each cigarette and every period of abstinence, to be determined. This novel methodology revealed that smokers suffered repeated mood deteriorations in-between cigarettes, and transitory mood improvements immediately after smoking. Heavy smokers reported the worst mood states in between cigarettes, but also the greatest mood normalization, which explains why their 'need' for cigarettes was strongest.


In later studies, we compared the daily mood patterns of cigarette smokers and nonsmokers. They provided comparative data on the daily moods experienced by cigarette smokers and nonsmokers. Some studies were conducted during the day, from breakfast to bedtime. Others were conducted with night shift workers. It was found that non-deprived smokers were generally similar to nonsmokers, whereas deprived smokers were significantly worse than either group. Thus smoking simply allowed normal/average moods to be maintained. Nicotine did not provide any real mood gains, whereas abstinent smokers suffered from increased stress, depression, and irritability. Furthermore, in some situations (e.g. night shift-workers), the moods of the active smokers were significantly worse than those of the nonsmokers.


Parrott AC (1993). Cigarette smoking: effects upon self-­rated feelings of stress and arousal over the  day.  Addictive Behaviors, 18, 389-­395.


Parrott AC, Joyce C (1993). Diurnal patterns of stress and arousal in cigarette smokers, deprived smokers, and non-smokers.  Human Psychopharmacology, 8, 21-28. PDF


Parrott AC (1994). Does cigarette smoking cause stress ?  Addiction, 89, 142-­144. PDF


Parrott AC (1994). Individual differences in stress and arousal during cigarette smoking. Psychopharmacology, 115, 389-396. PDF


Parrott AC (1994). Acute pharmacodynamic tolerance to the subjective effects of cigarette smoking. Psychopharmacology, 116, 93-97. PDF


Parrott AC (1995). Stress modulation over the day in cigarette smokers. Addiction, 90, 233-244.


Parrott AC (1995). Smoking cessation leads to reduced stress, but why ? International Journal of the Addictions, 30, 1509-1516.


Parrott AC, Garnham NJ, Wesnes K, Pincock C (1996). Cigarette smoking and abstinence: comparative effects upon cognitive task performance and mood state over 24 hours. Human Psychopharmacology, 11, 391-400. PDF


Jones MEE, Parrott AC (1997). Stress and arousal rhythms in smokers and nonsmokers working day and night shifts. Stress Medicine, 13, 91-97 PDF


Parrott, A.C. (2000)  Cigarette smoking: The gradual evolution of a research programme.  Psych-Talk, 24, 25-28. PDF


Parrott, A.C. (2000)  Tobacco/Nicotine Dependency: A direct cause of Psychobiological Distress?  Psych-Talk, 24, 29-31.



Cognitive skills of cigarette smokers and Nesbitt’s Paradox.


It has been suggested that nicotine is a cognitive enhancer, so that cigarettes provide smokers with a positive resource to boost their alertness. The empirical evidence for this notion is however very weak. We have therefore included cognitive tasks in many of our studies. In most studies, we found that the cognitive skills of deprived smokers were impaired, whereas the cognitive skills of the non-deprived smokers were similar to those of the nonsmokers. We have found some limited evidence for cognitive gains in smokers, although the evidence was not consistent, and generally we found no cognitive gains. Our overall conclusion is that although nicotine is potentially a cognitive enhancer, due to tolerance, regular smokers do not actually gain any real cognitive advantages from nicotine. Their cognitive abilities fluctuate – in a way similar to their mood states. So that they need regular hits of nicotine just to maintain normal levels of cognitive functioning. In Parrott (1998), I suggested that cognition was slightly improved post-cigarette, but then deteriorated in-between cigarettes, so that over the day cognition remained broadly neutral. Some of the relevant papers are listed in the above sections.


In the early 1970s, Nesbitt described a paradox which has confounded nicotine/smoking  researchers for many years. Namely, how can cigarettes make smokers feel more alert and more relaxed at the same time ? Andy Parrott's research has offered a simple resolution for the Paradox. Abstinence makes the smoker less alert and more stressed/irritable. Smoke inhalation restores these moods to normal - for a brief period. Nesbitt's Paradox simly reflects the relief of unpleasant abstinence effects. No actual gains in alertness or relaxation are involved.


Parrott AC, Roberts G (1991). Nicotine deprivation and nicotine reinstatement: effects upon a brief sustained attention task.  In: Effects of nicotine on biological systems. Adlkofer F, Thurau K (eds), Birkhauser, Basel (p485-490).


Parrott AC, Roberts G (1991). Smoking deprivation and cigarette reinstatement: effects upon visual  attention.  Journal of Psychopharmacology, 5, 402-­407.


Parrott AC (1992). Smoking and smoking cessation: effects upon human performance.  Journal of Smoking-­Related Disorders, 3, 43-­53.


O'Neill ST, Parrott AC (1992). Stress and arousal in sedative and stimulant cigarette smokers.  Psychopharmacology, 107, 442-­446. PDF


Wesnes K, Parrott AC (1992). Smoking, nicotine and human performance. In: Handbook of human performance, Vol 2. Smith A, Jones DM (eds). Academic press, London.


Parrott AC, Garnham NJ (1998). Comparative mood states and cognitive skills of cigarette smokers, deprived smokers, and non-smokers. Human Psychopharmacology, 13, 367-376. PDF


Parrott AC, Kaye F (1999). Daily uplifts, hassles, stresses, and cognitive failures, in cigarette smokers, abstaining smokers, and nonsmokers. Behavioral Pharmacology, 10, 639-646.


Parrott AC (1998). Nesbitt’s Paradox resolved ? stress and arousal modulation during cigarette smoking. Addiction, 93, 27-39. PDF


Heffernan TM, Ling J, Parrott AC, Buchanan T, Scholey AB, Rodgers J   (2005). Self-rated everyday and prospective memory abilities of cigarette smokers and non-smokers: a web based study. Drug & Alcohol Dependence 78, 235-241. PDF




Nicotine withdrawal, Nicotine Gum, and Smoking Cessation


Since nicotine withdrawal leads to mood impairments in regular smokers, this raises the question of how long it takes for these psychobiological deficits to develop. Received wisdom was that it could take 12-24 hours for abstinence symptoms to be apparent, but there was very little empirical data on this question - tobacco companies are not interested in this particular question! In our first study, Natasha Garnham investigated the cognitive skills and moods states of abstinent smokers, at two hour intervals over the day. Significant deficits were apparent from the first session onwards, with symptoms tending to worsen as the period of abstinence lengthened. Jo Thurkle and Mark Ward  covered the first three hours of abstinence, and found impairments at every session. Significant cognitive/mood abstinence  symptoms occurred after just one hour without nicotine. We have also looked at mood control in psychiatric patients, finding that they experience severe abstinence symptoms after brief periods without cigarettes. In our most recent study, Mark Slater assessed abstinence symptoms under two conditions: environmental stressor (difficult problem solving), and environmental relaxation (soothing music); abstinence symptoms became significantly worse during the high stressor condition. Debbie Craig and Jo-Ann Coomber compared the effects of temporary abstinence from cigarettes, at two different stages of the menstrual cycle. Abstinence symptoms were far stronger pre-menstrually than mid-cycle, when female smokers also reported less difficulty in abstaining.



Nicotine substitution devices have been developed to help people quit smoking. In an aelry series of studies, we investigated the cognitive performance effects of 2mg and 4mg nicotine gum, placebo gum, and normal cigarette smoking. Debbie Craig also established two smoking cessation clinics at health centers in  East London, where the utility of the nicotine gum was assessed. The most intriguing finding to emerge, was that self-rated feelings of stress were significantly reduced in those who quit smoking. This helped Andy Parrott to recognize the damaging effects of nicotine dependency.


Parrott AC, Winder G (1989). Nicotine chewing gum (2mg, 4mg) and cigarette smoking: comparative effects upon vigilance and heart rate.   Psychopharmacology, 97, 257-­261. PDF


Parrott AC, Craig D, Haines M, Winder GM (1991). Nicotine pilocrilex gum and sustained attention.  In: Effects of nicotine on biological systems. Adlkofer F, Thurau K (eds), Birkhauser, Basel (p559-564).


Parrott AC, Craig D (1992). Cigarette smoking and nicotine gum (0mg, 2mg, 4mg): effects upon four visual attention tasks.  Neuropsychobiology, 25, 34-­43.


Craig D, Parrott AC, Coomber JA (1992). Smoking cessation in women: effects of the menstrual cycle. International Journal of the Addictions, 27, 695-­704.


Parrott AC, Craig D (1995). Psychological functions served by nicotine gum. Addictive Behaviors, 20, 271-278. PDF


Parrott AC (1995). Smoking cessation leads to reduced stress, but why ? International Journal of the Addictions, 30, 1509-1516.


Parrott AC (1996). Smoking cessation counseling. In: Bayne R, Horton I, Bimrose J (eds.). New Directions in Counseling. Routledge, London.


Parrott A.C., Thurkle J. Ward M. (2000). Nicotine abstinence: time course of the mood and cognitive performance changes over 3 hours. 22nd International Congress of the Collegium Internationale Neuro-Psychopharmacologicum, Brussels July 2000. International Journal of Neuropsychopharmacology….


Other Psychoactive drugs



Caffeine use by day-shift workers and night-shift workers was investigated by Miranda Jones as part of her PhD. Other studies in her resaeh porgremmme involved nicotine use in shift workers. Some of these studies were supported by Unilever, who also provided the matched supplies of caffeinated and decaffeinated beverages.


Jones MEE, Parrott AC, Wesnes K (1997). The effects of caffeinated and decaffeinated tea and coffee on mood and cognition in shift workers. Paper presented at Annual Scientific Meeting of the Psychobiology Section of the British Psychological Society. British Psychological Society Proceedings.


Jones MEE, Parrott AC, Wesnes K (1997). The effects of caffeinated and decaffeinated beverages on cognitive performance, heart rate, and mood in shift workers. Paper presented at the Annual Conference of the British Association for Psychopharmacolgy. Journal of Psychopharmacology, 12, A42.



Anabolic steroid effects on human aggression were first investigated by Precilla Choi, when she was an undergraduate student at UEL. She continued her work at University College London, Nottingham University, and Keele University, and became a world leader in the field of research, prior to her untimely death. Clive Wilson-Fearon undertook a prospective anabolic steroid case study involving a "Mr. Universe" competitor, who was monitored for six months prior to, and during the actual competition.


Choi PYL, Parrott AC, Cowan D (1989). Adverse behavioural effects of anabolic steroids in athletes: a brief review.  Clinical Sports Medicine, 1, 183-­187.


Choi PYL, Parrott AC (1989). Illicit drug use in strength athletes (letter).  British Journal of Psychiatry, 154, 732-733.


Choi PYL, Parrott AC, Cowan D (1990). High dose anabolic steroids in strength athletes: effects upon hostility and aggression.  Human Psychopharmacology, 5, 349-356. PDF


Parrott AC, Choi PYL, Davies M (1994). Anabolic steroid use by amateur athletes: effects upon psychological mood states. Journal of Sports Medicine and Physical Fitness, 34, 292-298.


Wilson-Fearon C, Parrott AC (1999). Multiple drug use and dietary restraint in a Mr. Universe competitor: psychobiological effects. Perceptual and Motor Skills, 88, 579-580.



Cannabis has been investigated in a number of studies. The first to be undertaken by Andy Parrott were at Humboldt State University in Northern California, when he held a Fulbright Fellowship.   Most of the cannabis papers involved comparisons with MDMA, and are therefore listed in those sections.



Alcohol was investiagated by Vered Murgraff, when she investigated the effects of "risky single occasion drinking" or binge drinking in young people, as part of her PhD. We have also found that smoking is associated with reduced memory ability.


Murgraff V, Parrott AC, Bennett P (1998). Risky single occasion drinking amongst young people: a broad overview of research findings. Alcohol and Alcoholism, 33, 1-12


Ling J, Heffernan TM, Buchanan T, Scholey AB, Rodgers J, Parrott AC (2003). Effects of alcohol on subjective ratings of prospective and everyday memory deficits.   Alcoholism: Clinical and Experimental Research, 27, 970-974. PDF



Ketamine has been increasingly used as a recreational drug in recent years. Ketamine is a dissociative anaesthetic with powerful neurochemical  effects, and may cause long-lasting neuronal  damage. Helena Hamilton has assessed the cognitive integrity of drug-free ketamine abusers, in a collaborative study with Keith Wesnes’ Cognitive Drug Research in Reading.


Hamilton H, Turner JJD, Parrott AC, Hargaden N, Wesnes K (2000). Ketamine and polydrug abusers: comparative cognitive profiles. Paper submitted to the British Association for Psychopharmacolgy Annual Conference, Cambridge University July 2000. Journal of Psychopharmacology


The reliability and validity of the cognitive performance tests used in human psychopharmacology, were reviewed in a series of papers, published in 1991.



Parrott AC (1987). Assessment of psychological performance in applied situations. In:  Human psychopharmacology: measures and methods, vol 1. Hindmarch I, Stonier PD (eds). Wiley, Chichester.


Parrott AC (1991). Performance tests in human psychopharmacology (1): Test reliability and standardisation.  Human Psychopharmacology, 6, 1-­9. PDF


Parrott AC (1991). Performance tests in human psychopharmacology (2): Content validity, criterion validity, and face validity.  Human Psychopharmacology, 6, 91-­98. PDF


Parrott AC (1991). Performance tests in human psychopharmacology (3): Construct validity and test interpretation.  Human Psychopharmacology, 6, 197-­207. PDF


Parrott AC (1991). Psychoactive medicines: efficacy and side-­effects.  In: The Psychology of Health.  Pitts M, Phillips K (eds). Routledge, London.


Parrott AC (1991). Social drugs: effects upon health. In: The Psychology of Health. Pitts M, Phillips K (eds). Routledge, London.


Scopolamine, Promethazine, Cinnarazine.


These studies were conducted when Andy Parrott was Senior Psychologist at the Institute of Naval Medicine, Gosport Hampshire. The aim of the program was to recommend an effective drug for protection against sea-sickness, which displayed the least sedative profile of side-effects. The studies included the first placebo-controlled human performance studies undertaken at sea.


Parrott AC, Jones R (1985). Effects of transdermal scopolamine upon psychological performance at sea.  European Journal of Clinical Pharmacology, 28, 419-­423.


Parrott AC (1986). The effects of transdermal scopolamine and four doses of oral scopolamine (0.15, 0.3, 0.6, 1.2mg) upon psychological performance.  Psychopharmacology, 89, 347-­354. PDF


Parrott AC (1986). Transdermal scopolamine: effects of single and repeated patches upon aspects of vision.  Human Psychopharmacology, 1, 109-­115. PDF


Parrott AC (1986). Transdermal scopolamine: effects of single and repeated patches upon psychological task performance.  Neuropsychobiology, 17, 53-­59.


Parrott AC, Wesnes K (1987). Promethazine, scopolamine and cinnarizine: comparative time course of psychological performance effects.  Psychopharmacology, 92, 513-­519. PDF


Parrott AC (1988). Transdermal scopolamine: effects upon psychological performance and visual functioning at sea.  Human Psychopharmacology, 3, 119-­125. PDF


Parrott AC (1989). Transdermal scopolamine: a review of  its effects upon motion sickness, psychological performance, and physiological functioning.   Aviation Space and Environmental Medicine, 60, 1-­9.


Parrott AC, Golding JF, Pethybridge RJ (1990). The effects of single and repeated doses of oral scopolamine, cinnarizine and placebo upon psychological performance and physiological functioning.  Human Psychopharmacology, 5, 207-­216. PDF



Leeds Psychopharmacology Research: benzodiazepines, antidepressants, antihistamines, nootropics, and other drugs.


The follow studies were undertaken at Leeds University. The earliest studies were undertaken during an MRC-funded PhD entitled: ‘Concentration in Chronic Schizophrenia’. Later studies were conducted on benzodiazepines, antidepressants, antihistamines, and other drug types. These were undertaken when Andy Parrott was employed as a research assistant, then research fellow, to Professor Ian Hindmarch’s  Human Psychopharmacology Research Group to Leeds. Many of these studies involved the development of the Leeds Sleep Evaluation Questionnaire (Leeds SEQ).


Parrott AC, Hindmarch I (1975). Arousal and performance -­ the ubiquitous inverted-­U relationship; changes in response latency and arousal level in normal subjects induced by CNS stimulants, sedatives and tranquillisers. IRCS Medical Science, 3, 176.


Hindmarch I, Parrott AC (1977). A repeated dose comparison of nomifensine, imipramine and placebo on subjective assessments of sleep and objective measures of psychomotor performance. British Journal of Clinical Pharmacology, 4, 167s-­173s.


Hindmarch I, Parrott AC, Arenillas L (1977). A repeated dose comparison of dichloralphenazone, flunitrazepam, and amylobarbitone sodium, on aspects of sleep and early morning behaviour in normal subjects. British Journal of Clinical Pharmacology, 4, 229-­233.


Parrott AC, Hindmarch I (1978). Factor analysis of a sleep evaluation questionnaire.  Psychological Medicine, 8, 325-­329.


Hindmarch I, Parrott AC (1978). A repeated dose comparison of the side effects of five antihistamines.  Arzneimittel- ­Forschung (Drug Research), 28, 483-­486.


Hindmarch I, Parrott AC (1979). The effects of repeated nocturnal doses of clobazam, dipotassium chlorazepate and placebo, on subjective ratings of sleep and early morning behaviour, and objective measures of arousal, psychomotor performance and anxiety. British Journal of Clinical Pharmacology, 8, 325-­329.


Hindmarch I, Parrott AC, Lanza M (1979). The effects of an ergot alkaloid derivative (Hydergine) on aspects of psychomotor performance, arousal and cognitive processing ability.  Journal of Clinical Pharmacology, 19, 726-­732.


Parrott AC, Hindmarch I (1980). The Leeds Sleep Evaluation Questionnaire in psychopharmacological investigations -­ a review. Psychopharmacologia, 71, 173-­179. PDF


Parrott AC, Rogers PJ, Brownlie VA (1980). The effects of amphetamine and fenfluramine upon subjective self-­reports of sleep and morning awakening.  IRCS Medical Science, 8, 312.


Hindmarch I, Parrott AC, Stonier PD (1980). The effects of nomifensine and HOE 8476 upon car driving and related psychomotor performance.   Royal Society of Medicine International Symposium Series, 25, 47-­54.


Hindmarch I, Parrott AC, Hickey B, Clyde C (1980). An investigation into the effects of repeated doses of temazepam (40 and 60mg) upon aspects of sleep, early morning behaviour, and psychomotor performance in  normal subjects. Drugs under Experimental and Clinical Research, 6, 399-­406.


Parrott AC, Munton A (1981). Comparative effects of clobazam and diazepam upon psychological performance under different levels of background noise.   Royal Society of Medicine International Symposium Series, 43, 53-­57.


Parrott AC (1982). Critical flicker dusion thresholds and their relationship to other measures of alertness.  Pharmacopsychiatry, 15, 39-­43.


Parrott AC (1982). The effects of clobazam upon critical flicker fusion thresholds: a review.  Drug Development Research (Supplement 1), 57-­66. PDF


Parrott AC, Hindmarch I (1982). The effects of hydergine upon psychomotor performance, indices of alertness, and behaviour ratings, in studies involving normal and geriatric subjects.   British Journal of Clinical Practice, 16, (Supplement), 18-­20.


Parrott AC, Hindmarch I, Stonier PD (1982). Nomifensine, clobazam, and HOE 8476: effects on aspects of psychomotor performance and cognitive ability.  European Journal of Clinical Pharmacology, 23, 309-­313.


Stonier PD, Parrott AC, Hindmarch I  (1982). Clobazam in combination with nomifensine (HOE 8476): effects on mood, sleep, and psychomotor performance related to car driving.  Drug Development Research 1: 47-55. PDF


Parrott AC, Kentridge R (1982). Personal constructs of anxiety under the 1.5 benzodiazepine derivative clobazam, related to trait anxiety levels of the personality.  Psychopharmacology, 78, 353-­357. PDF


Parrott AC, Davies S (1983). Effects of a 1-­5 benzodiazepine derivative  upon performance in an experimental stress situation. Psychopharmacology, 79, 367-­369. PDF


Parrott AC (1985). Clobazam, personality, stress and performance.  Royal Society of Medicine International Symposium Series, 74, 47-­58.



Visual aesthetics.



Parrott AC (1982). Effects of paintings and music, both alone and in combination, upon emotional judgements.  Perceptual and Motor Skills, 54, 635-­641.


Parrott AC (1989). Aesthetic responses to a series of paintings by Paul Klee.  Perceptual and Motor Skills, 69, 339-­348.


Parrott AC (1990). Diabetes management: viewpoint of the patient.  Practical Diabetes, 7, 114-­118.


Parrott AC (1994). Aesthetic responses to traditional and modern paintings by art experts and nonexperts.  Perceptual and Motor Skills, 79, 297-298.