Skip to main content Accessibility help

We use cookies to distinguish you from other users and to provide you with a better experience on our websites. Close this message to accept cookies or find out how to manage your cookie settings.

Close cookie message
×
  1. Home
  2. Search

Refine search

Refine search

Access:
Content type:
Publication date:
Apply   From and To filters
Subject: Show more
Journals Show more
Publishers: Show more
Societies Show more
Series: Show more
Collections: Show more

Actions for selected content:

Select all | Deselect all
  • View selected items
  • Export citations
  • Download PDF (zip)
  • Save to Kindle
  • Save to Dropbox
  • Save to Google Drive

Save Search

You can save your searches here and later view and run them again in "My saved searches".

Please provide a title, maximum of 40 characters.
Cancel
×

29 results

Page 1 of 2

  • Index

  • Edited by Deepak Cyril D'Souza, Staff Psychiatrist, VA Connecticut Healthcare System; Professor of Psychiatry, Yale University School of Medicine, David Castle, University of Tasmania, Australia, Sir Robin Murray, Honorary Consultant Psychiatrist, Psychosis Service at the South London and Maudsley NHS Trust; Professor of Psychiatric Research at the Institute of Psychiatry
  • Book: Marijuana and Madness
  • Published online: 12 May 2023
  • Print publication: 01 June 2023, pp 357-366

  • Chapter 22 - The Acute Effects of Cannabinoids in Patients with Psychotic Illness

  • from Part VII - Cannabinoids and Schizophrenia: Aetiopathology and Treatment Implications
  • Edited by Deepak Cyril D'Souza, Staff Psychiatrist, VA Connecticut Healthcare System; Professor of Psychiatry, Yale University School of Medicine, David Castle, University of Tasmania, Australia, Sir Robin Murray, Honorary Consultant Psychiatrist, Psychosis Service at the South London and Maudsley NHS Trust; Professor of Psychiatric Research at the Institute of Psychiatry
  • Book: Marijuana and Madness
  • Published online: 12 May 2023
  • Print publication: 01 June 2023, pp 225-239

  • Summary

    People with psychosis and those at clinical high risk (CHR) for this syndrome have significantly higher prevalence of cannabis use compared to the general population. Furthermore, cannabis use can negatively impact the course and treatment outcomes in psychosis. Understanding the acute subjective and cognitive effects of cannabis and cannabinoids in this population is necessary if we are to disentangle the reasons for the increased prevalence of use; and also to help design interventions. There is little evidence to support the ’self-medication’ hypothesis, in its original form. Among principal phyto-cannabinoids, while THC exacerbates positive and cognitive symptoms of psychosis, cannabidiol lacks these effects and may even improve these symptoms. With the liberalization of cannabis laws in many countries, cannabis and cannabis-based products will be more accessible to both individuals with psychotic disorders and those at risk for psychosis. This chapter summarizes the literature regarding acute effects of cannabis and cannabinoids in people at CHR and with established psychosis.

  • Contents

  • Edited by Deepak Cyril D'Souza, Staff Psychiatrist, VA Connecticut Healthcare System; Professor of Psychiatry, Yale University School of Medicine, David Castle, University of Tasmania, Australia, Sir Robin Murray, Honorary Consultant Psychiatrist, Psychosis Service at the South London and Maudsley NHS Trust; Professor of Psychiatric Research at the Institute of Psychiatry
  • Book: Marijuana and Madness
  • Published online: 12 May 2023
  • Print publication: 01 June 2023, pp v-vi

  • Preface

  • Edited by Deepak Cyril D'Souza, Staff Psychiatrist, VA Connecticut Healthcare System; Professor of Psychiatry, Yale University School of Medicine, David Castle, University of Tasmania, Australia, Sir Robin Murray, Honorary Consultant Psychiatrist, Psychosis Service at the South London and Maudsley NHS Trust; Professor of Psychiatric Research at the Institute of Psychiatry
  • Book: Marijuana and Madness
  • Published online: 12 May 2023
  • Print publication: 01 June 2023, pp xi-xii

Marijuana and Madness
  • 3rd edition
  • Edited by Deepak Cyril D'Souza, David Castle, Sir Robin Murray
  • Published online: 12 May 2023
  • Print publication: 01 June 2023
  • An updated third edition of this award-winning book provides a comprehensive overview of the complex associations between cannabis and mental illness. Organised into easy to navigate sections, the book has been fully revised to feature eight entirely new chapters covering important novel aspects. Marijuana and Madness incorporates new research findings on the potential use of cannabinoids, and synthetic cannabinoids, in an array of mental illnesses, balanced against the potential adverse effects. The associations between cannabis and psychosis, developing putative models of 'cannabis induced' psychosis and pathways to schizophrenia are all covered. The book importantly discusses the impact of exposure to cannabis at various stages of neurodevelopment (in utero, in childhood, and during adolescence) and it thoroughly reviews the treatments for cannabis dependence and health policy implications of the availability of increasingly high potency cannabis. This book will quickly become an essential resource for all members of the mental health team.

  • Differential Cognitive Performance in Females and Males with Regular Cannabis Use

  • Ashley M. Schnakenberg Martin, Deepak Cyril D’Souza, Sharlene D. Newman, William P. Hetrick, Brian F. O’Donnell
  • Journal: Journal of the International Neuropsychological Society / Volume 27 / Issue 6 / July 2021
  • Published online by Cambridge University Press: 15 July 2021, pp. 570-580
    • Article
      • You have access
      • Open access
    • PDF
    • HTML
    • Export citation
  • Objectives:

    Preclinical and clinical studies suggest that males and females may be differentially affected by cannabis use. This study evaluated the interaction of cannabis use and biological sex on cognition, and the association between observed cognitive deficits and features of cannabis use.

    Methods:

    Cognitive measures were assessed in those with regular, ongoing, cannabis use (N = 40; 22 female) and non-using peers (N = 40; 23 female). Intelligence, psychomotor speed, and verbal working memory were measured with the Wechsler Abbreviated Scale of Intelligence, Digit Symbol Test, and Digit Span and Hopkins Verbal Learning Test, respectively. Associations between cognitive measures and cannabis use features (e.g., lifetime cannabis use, age of initiation, time since last use of cannabis, recent high-concentration tetrahydrocannabinoid exposure) were also evaluated.

    Results:

    No main effects of group were observed across measures. Significant interactions between group and biological sex were observed on measures of intelligence, psychomotor speed, and verbal learning, with greatest group differences observed between males with and without regular cannabis use. Psychomotor performance was negatively correlated with lifetime cannabis exposure. Female and male cannabis use groups did not differ in features of cannabis use.

    Conclusions:

    Findings suggest that biological sex influences the relationship between cannabis and cognition, with males potentially being more vulnerable to the neurocognitive deficits related to cannabis use.

  • Psychosocial and pharmacological treatments for cannabis use disorder and mental health comorbidities: a narrative review

  • Rachel Lees, Lindsey A. Hines, Deepak Cyril D'Souza, George Stothart, Marta Di Forti, Eva Hoch, Tom P. Freeman
  • Journal: Psychological Medicine / Volume 51 / Issue 3 / February 2021
  • Published online by Cambridge University Press: 04 February 2021, pp. 353-364
  • Print publication: February 2021

  • Cannabis is the most widely used illicit drug worldwide, and it is estimated that up to 30% of people who use cannabis will develop a cannabis use disorder (CUD). Demand for treatment of CUD is increasing in almost every region of the world and cannabis use is highly comorbid with mental disorders, where sustained use can reduce treatment compliance and increase risk of relapse. In this narrative review, we outline evidence for psychosocial and pharmacological treatment strategies for CUD, both alone and when comorbid with psychosis, anxiety or depression. Psychosocial treatments such as cognitive behavioural therapy, motivational enhancement therapy and contingency management are currently the most effective strategy for treating CUD but are of limited benefit when comorbid with psychosis. Pharmacological treatments targeting the endocannabinoid system have the potential to reduce cannabis withdrawal and cannabis use in CUD. Mental health comorbidities including anxiety, depression and psychosis hinder effective treatment and should be addressed in treatment provision and clinical decision making to reduce the global burden of CUDs. Antipsychotic medication may decrease cannabis use and cannabis craving as well as psychotic symptoms in patients with CUD and psychosis. Targeted treatments for anxiety and depression when comorbid with CUD are feasible.

  • Characterizing psychosis-relevant phenomena and cognitive function in a unique population with isolated, chronic and very heavy cannabis exposure

  • Deepak Cyril D'Souza, Suhas Ganesh, Jose Cortes-Briones, Michael H. Campbell, Maisha K. Emmanuel
  • Journal: Psychological Medicine / Volume 50 / Issue 14 / October 2020
  • Published online by Cambridge University Press: 16 October 2019, pp. 2452-2459
  • Print publication: October 2020
  • Background

    The literature on psychosis-relevant outcomes in cannabis users does not adequately address the confounding effects of other substance use/misuse and psychiatric disorders.

    Methods

    We studied a unique population for whom cannabis use is central and necessary to their way of life. They are forbidden from using other substances, including tobacco and alcohol. Their use of cannabis is heavy, chronic, and begins early. The cases were compared with matched controls who did not use cannabis, alcohol, or drugs. The controls were from the same location and shared similar beliefs and lifestyle, except for cannabis use. Attenuated psychosis-relevant phenomena were assessed with the Schizotypal Personality Questionnaire (SPQ) and cognitive functioning with a culture-neutral computerized cognitive battery.

    Results

    Fifteen cases and 12 matched controls were studied. The cases averaged >30 000 lifetime cannabis exposures. Relative to controls, the cases had significantly higher mean (s.d.) SPQ scores 24 (14.32) v. 13 (8.92), p = 0.031; and poorer cognitive performance, reflected by a lower mean (s.d.) composite cognitive score −0.23 (0.32) v. +0.28 (0.52), p = 0.03. Moderate to large effect sizes were noted for differences in tests of attention, psychomotor speed, working memory, cognitive flexibility, visuo-spatial processing, and verbal memory. A subsample of cases had higher SPQ scores and worse cognitive performance than their siblings not using cannabis.

    Conclusion

    Heavy, chronic, and early cannabis use that is not confounded by other drug use is associated with psychosis-relevant phenomena and cognitive deficits. The findings are relevant to the evolving attitudes and laws about cannabis.

  • 2181 Age-related change in 5-HT6 receptor availability in healthy male volunteers measured with 11C-GSK215083 PET

  • Rajiv Radhakrishnan, Nabeel Nabulsi, Edward Gaiser, Jean-Dominique Gallezot, Shannan Henry, Beata Planeta, Shu-fei Lin, Jim Ropchan, Wendol Williams, Evan Morris, Deepak Cyril D’Souza, Yiyun Huang, Richard E. Carson, David Matuskey
  • Journal: Journal of Clinical and Translational Science / Volume 2 / Issue S1 / June 2018
  • Published online by Cambridge University Press: 21 November 2018, pp. 3-4
    • Article
      • You have access
      • Open access
    • PDF
    • Export citation

  • OBJECTIVES/SPECIFIC AIMS: The serotonin receptor 6 (5-HT6) is a potential therapeutic target given its distribution in brain regions that are important in depression, anxiety, and cognition. This study sought to investigate the effects of age on 5-HT6 receptor availability using 11C GSK215083, a PET ligand with affinity for 5-HT6 in the striatum and 5-HT2A in the cortex. METHODS/STUDY POPULATION: In total, 28 healthy male subjects (age range: 23–52 years) were scanned with 11C-GSK215083 on the HR+PET scanner. Time-activity curves in regions-of-interest were fitted with multilinear analysis-1 method. Binding potentials (BPND) were calculated using cerebellum as the reference region and corrected for partial volume effects. RESULTS/ANTICIPATED RESULTS: In 5-HT6 rich areas, regional 11C-GSK215083 displayed a negative correlation between BPND and age in the caudate (r=−0.41, p=0.03) (14% change per decade), and putamen (r=−0.30, p=0.04) (11% change per decade), but not in the ventral striatum and pallidum. Negative correlation with age was also seen in cortical regions (r=−0.41, p=0.03) (7% change per decade), consistent with the literature on 5-HT2A availability. DISCUSSION/SIGNIFICANCE OF IMPACT: This is the first in vivo study in humans to examine the effect of age on 5-HT6 receptor availability. The study demonstrated a significant age-related decline in 5-HT6 availability (BPND) in the caudate and putamen.

Page 1 of 2