Effects of Extended Cannabis Abstinence on Cognitive Outcomes in Cannabis Dependent Patients with Schizophrenia vs Non-Psychiatric Controls.
Rachel A Rabin, Mera S Barr, Michelle S Goodman, Yarissa Herman, Konstantine K. Zakzanis, Stephen J. Kish, Michael Kiang, Gary Remington, Tony P. George
Neuropsychopharmacology October 2017 DOI: 10.1038/npp.2017.85 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Observational cohort (28-day cannabis abstinence paradigm) Cross-sectional Peer reviewed |
|---|---|
| Sample size | 39 |
| Population | Cannabis-dependent male patients with schizophrenia and non-psychiatric male cannabis-dependent controls |
| Duration | 28 days of cannabis abstinence; cognition assessed on day 0, 14, and 28; clinical symptoms assessed weekly |
| Measures | Hopkins Verbal Learning Test-Revised (HVLT-R), comprehensive neuropsychological battery, twice weekly urinalysis for urinary THC-COOH |
| Topics | Cannabis |
| Key findings | Schizophrenia-abstainers showed improvement over time on the Hopkins Verbal Learning Test-Revised (F(2,14)=4.73, p<0.03; d=1.07), with lesser improvement in non-psychiatric control abstainers (d=0.66) and on other cognitive measures in both groups. The authors suggest verbal memory and learning may improve with cannabis abstinence but that larger, more definitive studies are needed. |
Abstract
Cross-sectional studies of the effects of cannabis on cognition in schizophrenia have produced mixed results. Heavy and persistent cannabis use in schizophrenia is a common clinical problem, and effects of controlled abstinence from cannabis in these patients have not been carefully evaluated. The present study sought to determine the effects of cannabis abstinence on cognition in patients with schizophrenia and co-occurring cannabis dependence. We utilized a 28-day cannabis abstinence paradigm to investigate the state-dependent effects of cannabis on select cognitive outcomes in cannabis-dependent patients with schizophrenia and non-psychiatric controls. Nineteen patients and 20 non-psychiatric male cannabis-dependent participants underwent 28 days of cannabis abstinence. Cognition was assessed on day 0, 14, and 28 using a comprehensive neuropsychological battery. Clinical symptoms were assessed weekly. Abstinence was facilitated by contingency reinforcement confirmed by twice weekly urinalysis. Forty-two percent of patients and 55% of controls achieved end-point abstinence (p=0.53), which was biochemically-verified (day 28 urinary THC-COOH <20 ng/ml). In this preliminary study, schizophrenia-abstainers demonstrated improvements in Hopkins Verbal Learning Test-Revised (HVLT-R) performance over time [F(2,14)=4.73, p<0.03] (d=1.07). Lesser improvements on HVLT-R were observed in non-psychiatric control abstainers (d=0.66), and with abstinence on other cognitive test measures, in both patients and controls. Verbal memory and learning may improve in schizophrenia and control subjects with cannabis abstinence, but larger more definitive studies are needed. Our findings underscore the importance of developing effective interventions for cannabis use disorders in schizophrenia.
Comparable studies
Other observational and cohort studies on cannabis, most cited first.
| Study | Year | Design | Participants |
|---|---|---|---|
| High-potency cannabis and the risk of psychosis People with first episode of psychosis and healthy controls from the local population | 2009 | Case-control study | n = 454 |
| Ayahuasca-Assisted Therapy for Addiction: Results from a Preliminary Observational Study in Canada Rural aboriginal population | 2013 | Observational study | |
| Impaired cognitive performance in drug free users of recreational ecstasy (MDMA) Otherwise healthy young people | 2000 | Observational | |
| Continued cannabis use and risk of incidence and persistence of psychotic symptoms: 10 year follow-up cohort study Individuals from the general population in Germany aged 14-24 at baseline | 2011 | Observational cohort | n = 1,923 |
| Cannabis-induced psychosis and subsequent schizophrenia-spectrum disorders: follow-up study of 535 incident cases Patients treated for cannabis-induced psychotic symptoms in Denmark between 1994 and... | 2005 | Observational cohort | n = 535 |
Citations in the library
Cited by 7
- Association between cannabis use and symptom dimensions in schizophrenia spectrum disorders: an individual participant data meta-analysis on 3053 individuals EClinicalMedicine September 8, 2023
- A Meta-Analysis of Cannabis Research: Evidence of Lasting Neurocognitive Effects Continues to be Lacking Cannabis May 6, 2026
- Multi-dimensional recovery trajectories in cannabis-induced psychosis: A systematic review examining symptomatic, functional, cognitive, and subjective outcomes. Asian Journal of Psychiatry April 1, 2026
- Sensory gating in tobacco-naïve cannabis users is unaffected by acute nicotine administration. Psychopharmacology May 2022
- Consensus paper of the WFSBP task force on cannabis, cannabinoids and psychosis The World Journal of Biological Psychiatry March 22, 2022
and 2 more in the library
Cites 11
- Effects of cannabis use on outcomes of psychotic disorders: systematic review The British Journal of Psychiatry October 31, 2008
- The Impact of Cannabis Use on Cognitive Functioning in Patients With Schizophrenia: A Meta-analysis of Existing Findings and New Data in a First-Episode Sample Schizophrenia Bulletin July 25, 2010
- The Effect of Cannabis Use and Cognitive Reserve on Age at Onset and Psychosis Outcomes in First-Episode Schizophrenia Schizophrenia Bulletin March 9, 2011
- Psychosis reactivity to cannabis use in daily life: an experience sampling study The British Journal of Psychiatry May 31, 2010
- Neurocognitive functions of heavy cannabis using schizophrenia patients European Psychiatry June 28, 2011
and 6 more in the library