Skip to main content Accessibility help
Hostname: page-component-888d5979f-bkf9v Total loading time: 0.42 Render date: 2021-10-26T10:00:13.424Z Has data issue: true Feature Flags: { "shouldUseShareProductTool": true, "shouldUseHypothesis": true, "isUnsiloEnabled": true, "metricsAbstractViews": false, "figures": true, "newCiteModal": false, "newCitedByModal": true, "newEcommerce": true, "newUsageEvents": true }

The effects of cannabis on memory function in users with and without a psychotic disorder: findings from a combined meta-analysis

Published online by Cambridge University Press:  10 September 2015

T. Schoeler
Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience, King's College London, De Crespigny Park, London SE5 8AF, UK
J. Kambeitz
Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience, King's College London, De Crespigny Park, London SE5 8AF, UK Department of Psychiatry, Ludwig-Maximilian-University Munich, Nuβbaumstr. 7, 80336 Munich, Germany
I. Behlke
Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience, King's College London, De Crespigny Park, London SE5 8AF, UK Institute of Psychology, Univeristy of Osnabrueck, Seminarstr. 20, 49074 Osnabrueck, Germany
R. Murray
Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience, King's College London, De Crespigny Park, London SE5 8AF, UK
S. Bhattacharyya*
Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience, King's College London, De Crespigny Park, London SE5 8AF, UK
* Address for correspondence: S. Bhattacharyya, M.B.B.S., M.D., Ph.D., Department of Psychosis Studies, Institute of Psychiatry, King's College London, De Crespigny Park, London SE5 8AF, UK. (Email:



Effect of cannabis use on memory function is a contentious issue, with effects being different in healthy individuals and patients with psychosis.


Employing a meta-analytic approach we investigated the effects of cannabis use on memory function in patients with psychosis and healthy individuals, and the effect of diagnosis, memory dimension and moderating factors. A total of 88 studies were identified through a systematic literature search, investigating healthy (n = 7697) and psychotic (n = 3261) individuals. Standardized mean differences between the cannabis user and non-user groups on memory tasks were estimated using random-effects models and the effect-size statistic Cohen's d. Effects of potential moderating factors were tested using mixed-effects models and subgroup analyses.


We found that cannabis use was associated with significantly (p ⩽ 0.05) impaired global (d = 0.27) and prospective memory (d = 0.61), verbal immediate (d = 0.40) and delayed (d = 0.36) recall as well as visual recognition (d = 0.41) in healthy individuals, but a better global memory (d = −0.11), visual immediate recall (d = −0.73) and recognition (d = −0.42) in patients. Lower depression scores and younger age appeared to attenuate the effects of cannabis on memory. Cannabis-using patients had lower levels of depression and were younger compared with non-using patients, whilst healthy cannabis-users had higher depression scores than age-matched non-users. Longer duration of abstinence from cannabis reduced the effects on memory in healthy and patient users.


These results suggest that cannabis use is associated with a significant domain-specific impairment in memory in healthy individuals but not in cannabis-using patients, suggesting that they may represent a less developmentally impaired subgroup of psychotic patients.

Original Articles
Copyright © Cambridge University Press 2015 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)


Bahorik, AL, Newhill, CE, Eack, SM (2013). Neurocognitive functioning of individuals with schizophrenia: using and not using drugs. Schizophrenia Bulletin 40, 856867.CrossRefGoogle Scholar
Beller, EM, Glasziou, PP, Altman, DG, Hopewell, S, Bastian, H, Chalmers, I, Gøtzsche, PC, Lasserson, T, Tovey, D (2013). PRISMA for abstracts: reporting systematic reviews in journal and conference abstracts. PLoS Medicine 10, e1001419.CrossRefGoogle ScholarPubMed
Benedict, RHB, Schretlen, D, Groninger, L, Brandt, J (1998). Hopkins Verbal Learning Test–revised: normative data and analysis of inter-form and test–retest reliability. Clinical Neuropsychologist 12, 4355.CrossRefGoogle Scholar
Bhattacharyya, S, Atakan, Z, Martin-Santos, R, Crippa, JA, Kambeitz, J, Prata, D, Williams, S, Brammer, M, Collier, DA, McGuire, PK (2012). Preliminary report of biological basis of sensitivity to the effects of cannabis on psychosis: AKT1 and DAT1 genotype modulates the effects of δ-9-tetrahydrocannabinol on midbrain and striatal function. Molecular Psychiatry 17, 11521155.CrossRefGoogle ScholarPubMed
Bhattacharyya, S, Fusar-Poli, P, Borgwardt, S, Martin-Santos, R, Nosarti, C, O'Carroll, C, Allen, P, Seal, ML, Fletcher, PC, Crippa, JA, Giampietro, V, Mechelli, A, Atakan, Z, McGuire, P (2009). Modulation of mediotemporal and ventrostriatal function in humans by Δ9-tetrahydrocannabinol: a neural basis for the effects of Cannabis sativa on learning and psychosis. Archives of General Psychiatry 66, 442451.CrossRefGoogle ScholarPubMed
Bolla, KI, Brown, K, Eldreth, D, Tate, K, Cadet, JL (2002). Dose-related neurocognitive effects of marijuana use. Neurology 59, 13371343.CrossRefGoogle ScholarPubMed
Borenstein, M, Hedges, LV, Higgins, JP, Rothstein, HR (2011). Introduction to Meta-Analysis. Wiley: Chichester.Google ScholarPubMed
Bowman, M, Pihl, RO (1973). Cannabis: psychological effects of chronic heavy use. Psychopharmacologia 29, 159170.CrossRefGoogle ScholarPubMed
Bugra, H, Studerus, E, Rapp, C, Tamagni, C, Aston, J, Borgwardt, S, Riecher-Rössler, A (2013). Cannabis use and cognitive functions in at-risk mental state and first episode psychosis. Psychopharmacology (Berlin) 230, 299308.CrossRefGoogle ScholarPubMed
Burt, DB, Zembar, MJ, Niederehe, G (1995). Depression and memory impairment: a meta-analysis of the association, its pattern, and specificity. Psychological Bulletin 117, 285305.CrossRefGoogle ScholarPubMed
Carey, KB, Carey, MP, Simons, JS (2003). Correlates of substance use disorder among psychiatric outpatients: focus on cognition, social role functioning and psychiatric status. Journal of Nervous and Mental Disease 191, 300308.CrossRefGoogle ScholarPubMed
Cunha, PJ, Rosa, PGP, Ayres, Ade M, Duran, FLS, Santos, LC, Scazufca, M, Menezes, PR, dos Santos, B, Murray, RM, Crippa, JAS, Busatto, GF, Schaufelberger, MS (2013). Cannabis use, cognition and brain structure in first-episode psychosis. Schizophrenia Research 147, 209215.CrossRefGoogle ScholarPubMed
Curran, VH, Brignell, C, Fletcher, S, Middleton, P, Henry, J (2002). Cognitive and subjective dose–response effects of acute oral Δ9-tetrahydrocannabinol (THC) in infrequent cannabis users. Psychopharmacology (Berlin) 164, 6170.CrossRefGoogle Scholar
D'Souza, DC, Abi-Saab, WM, Madonick, S, Forselius-Bielen, K, Doersch, A, Braley, G, Gueorguieva, R, Cooper, TB, Krystal, JH (2005). Δ−9-Tetrahydrocannabinol effects in schizophrenia: implications for cognition, psychosis, and addiction. Biological Psychiatry 57, 594608.CrossRefGoogle ScholarPubMed
D'Souza, DC, Perry, E, MacDougall, L, Ammerman, Y, Cooper, T, Wu, YT, Braley, G, Gueorguieva, R, Krystal, JH (2004). The psychotomimetic effects of intravenous Δ−9-tetrahydrocannabinol in healthy individuals: implications for psychosis. Neuropsychopharmacology 29, 15581572.CrossRefGoogle Scholar
Donoghue, K, Doody, GA (2012). Effect of illegal substance use on cognitive function in individuals with a psychotic disorder, a review and meta-analysis. Neuropsychology 26, 785801.CrossRefGoogle ScholarPubMed
Donoghue, K, Mazzoncini, R, Hart, J, Zanelli, J, Morgan, C, Dazzan, P, Morgan, KD, Murray, RM, Jones, PB, Doody, GA (2012). The differential effect of illicit drug use on cognitive function in first-episode psychosis and healthy controls. Acta Psychiatrica Scandinavica 125, 400411.CrossRefGoogle ScholarPubMed
Eichenbaum, H (1993). Memory, Amnesia, and the Hippocampal System. The MIT Press: Cambridge, MA.Google Scholar
Englund, A, Morrison, PD, Nottage, J, Hague, D, Kane, F, Bonaccorso, S, Stone, JM, Reichenberg, A, Brenneisen, R, Holt, D (2013). Cannabidiol inhibits THC-elirefd paranoid symptoms and hippocampal-dependent memory impairment. Journal of Psychopharmacology 27, 1927.CrossRefGoogle ScholarPubMed
Ferraro, L, Russo, M, O'Connor, J, Wiffen, BDR, Falcone, MA, Sideli, L, Gardner-Sood, P, Stilo, S, Trotta, A, Dazzan, P, Mondelli, V, Taylor, H, Friedman, B, Sallis, H, La Cascia, C, La Barbera, D, David, AS, Reichenberg, A, Murray, R, Di Forti, M (2013). Cannabis users have higher premorbid IQ than other patients with first onset psychosis. Schizophrenia Research 150, 129135.CrossRefGoogle ScholarPubMed
Fletcher, PC, Honey, GD (2006). Schizophrenia, ketamine and cannabis: evidence of overlapping memory deficits. Trends in Cognitive Sciences 10, 167174.CrossRefGoogle ScholarPubMed
Fried, PA, Watkinson, B, Gray, R (2005). Neurocognitive consequences of marihuana – a comparison with pre-drug performance. Neurotoxicology and Teratology 27, 231239.CrossRefGoogle ScholarPubMed
Gonzalez, R, Carey, C, Grant, I (2002). Nonacute (residual) neuropsychological effects of cannabis use: a qualitative analysis and systematic review. Journal of Clinical Pharmacology 42 (11 Suppl.), 48S57S.CrossRefGoogle ScholarPubMed
Grant, I, Gonzales, R, Carey, CL, Natarajan, L, Wolfson, T (2003). Non-acute (residual) neurocognitive effects of cannabis use: a meta-analytic study. Journal of the International Neuropsychological Society 9, 679689.CrossRefGoogle ScholarPubMed
Gruber, SA, Sagar, KA, Dahlgren, MK, Racine, M, Lukas, SE (2012). Age of onset of marijuana use and executive function. Psychology of Addictive Behaviors 26, 496506.CrossRefGoogle ScholarPubMed
Hardwick, S, King, LA (2008). Home Office Cannabis Potency Study 2008. United Kingdom: Home Office Scientific Development Branch: St Albans.Google Scholar
Herkenham, M, Lynn, AB, Little, MD, Johnson, MR, Melvin, LS, De Costa, BR, Rice, KC (1990). Cannabinoid receptor localization in brain. Proceedings of the National Academy of Sciences of the USA 87, 19321936.CrossRefGoogle ScholarPubMed
Higgins, JP, Green, S (editors) (2008). Cochrane Handbook for Systematic Reviews of Interventions. Wiley Online Library: Chichester.CrossRefGoogle Scholar
Hulicka, IM (1966). Age differences in Wechsler Memory Scale scores. Journal of Genetic Psychology 109, 135145.CrossRefGoogle ScholarPubMed
Iversen, L (2003). Cannabis and the brain. Brain 126, 12521270.CrossRefGoogle Scholar
Jager, G, Kahn, RS, Van Den Brink, W, Van Ree, JM, Ramsey, NF (2006). Long-term effects of frequent cannabis use on working memory and attention: an fMRI study. Psychopharmacology (Berlin) 185, 358368.CrossRefGoogle ScholarPubMed
Jockers-Scherubl, MC, Wolf, T, Radzei, N, Schlattmann, P, Rentzsch, J, Gomez-Carrillo de Castro, A, Kuhl, KP (2007). Cannabis induces different cognitive changes in schizophrenic patients and in healthy controls. Progress in Neuro-Psychopharmacology and Biological Psychiatry 31, 10541063.CrossRefGoogle ScholarPubMed
Kambeitz, JP, Bhattacharyya, S, Kambeitz-Ilankovic, LM, Valli, I, Collier, DA, McGuire, P (2012). Effect of BDNF val66met polymorphism on declarative memory and its neural substrate: a meta-analysis. Neuroscience and Biobehavioral Reviews 36, 21652177.CrossRefGoogle Scholar
Kanayama, G, Rogowska, J, Pope, HG, Gruber, SA, Yurgelun-Todd, DA (2004). Spatial working memory in heavy cannabis users: a functional magnetic resonance imaging study. Psychopharmacology (Berlin) 176, 239247.CrossRefGoogle ScholarPubMed
Korver, N, Nieman, DH, Becker, HE, van de Fliert, JR, Dingemans, PH, de Haan, L, Spiering, M, Schmitz, N, Linszen, DH (2010). Symptomatology and neuropsychological functioning in cannabis using subjects at ultra-high risk for developing psychosis and healthy controls. Australian and New Zealand Journal of Psychiatry 44, 230236.CrossRefGoogle ScholarPubMed
Koskinen, J, Löhönen, J, Koponen, H, Isohanni, M, Miettunen, J (2010). Rate of cannabis use disorders in clinical samples of patients with schizophrenia: a meta-analysis. Schizophrenia Bulletin 36, 11151130.CrossRefGoogle ScholarPubMed
Lane, SD, Cherek, DR, Lieving, LM, Tcheremissine, OV (2005). Marijuana effects on human forgetting functions. Journal of the Experimental Analysis of Behavior 83, 6783.CrossRefGoogle ScholarPubMed
Leeson, VC, Harrison, I, Ron, MA, Barnes, TR, Joyce, EM (2012). The effect of cannabis use and cognitive reserve on age at onset and psychosis outcomes in first-episode schizophrenia. Schizophrenia Bulletin 38, 873880.CrossRefGoogle ScholarPubMed
Linszen, DH, Dingemans, PM, Nugter, MA, Van der Does, AJ, Scholte, WF, Lenior, MA (1997). Patient attributes and expressed emotion as risk factors for psychotic relapse. Schizophrenia Bulletin 23, 119130.CrossRefGoogle ScholarPubMed
Løberg, E-M, Hugdahl, K (2009). Cannabis use and cognition in schizophrenia. Frontiers in Human Neuroscience 3, 53.CrossRefGoogle ScholarPubMed
Løberg, EM, Hugdahl, K, Jørgensen, HA (2008). Lower neurocognitive vulnerability in schizophrenia with a history of cannabis abuse? Schizophrenia Research 98, 73.CrossRefGoogle Scholar
Lutgens, D, Lepage, M, Iyer, S, Malla, A (2014). Predictors of cognition in first episode psychosis. Schizophrenia Research 152, 164169.CrossRefGoogle ScholarPubMed
Matochik, JA, Eldreth, DA, Cadet, JL, Bolla, KI (2005). Altered brain tissue composition in heavy marijuana users. Drug and Alcohol Dependence 77, 2330.CrossRefGoogle ScholarPubMed
McDermott, LM, Ebmeier, KP (2009). A meta-analysis of depression severity and cognitive function. Journal of Affective Disorders 119, 18.CrossRefGoogle ScholarPubMed
Meier, MH, Caspi, A, Ambler, A, Harrington, H, Houts, R, Keefe, RS, McDonald, K, Ward, A, Poulton, R, Moffitt, TE (2012). Persistent cannabis users show neuropsychological decline from childhood to midlife. Proceedings of the National Academy of Sciences of the USA 109, E2657E2664.CrossRefGoogle ScholarPubMed
Miles, H, Johnson, S, Amponsah-Afuwape, S, Finch, E, Leese, M, Thornicroft, G (2003). Characteristics of subgroups of individuals with psychotic illness and a comorbid substance use disorder. Psychiatric Services 54, 554561.CrossRefGoogle Scholar
Moreno-Granados, JM, Ferrín, M, Salcedo-Marín, DM, Ruiz-Veguilla, M (2014). Neuropsychological assessment of memory in child and adolescent first episode psychosis: cannabis and the «paradox effect». Revista Brasileira de Psiquiatria 7, 1324.Google ScholarPubMed
Morrison, PD, Zois, V, McKeown, DA, Lee, TD, Holt, DW, Powell, JF, Kapur, S, Murray, RM (2009). The acute effects of synthetic intravenous Δ9-tetrahydrocannabinol on psychosis, mood and cognitive functioning. Psychological Medicine 39, 16071616.CrossRefGoogle ScholarPubMed
Moss, HB, Chen, CM, Yi, HY (2013). Early adolescent patterns of alcohol, cigarettes, and marijuana polysubstance use and young adult substance use outcomes in a nationally representative sample. Drug and Alcohol Dependence 136, 5162.CrossRefGoogle Scholar
Murray, RM, Lewis, SW (1987). Is schizophrenia a neurodevelopmental disorder? British Medical Journal (Clinical Research ed.) 295, 681682.CrossRefGoogle ScholarPubMed
Murray, RM, Paparelli, A, Morrison, PD, Marconi, A, Di Forti, M (2013). What can we learn about schizophrenia from studying the human model, drug-induced psychosis? American Journal of Medical Genetics Part B: Neuropsychiatric Genetics 162B, 661670.CrossRefGoogle ScholarPubMed
Nakamura, EM, Da Silva, EA, Concilio, GV, Adrian Wilkinson, D, Masur, J (1991). Reversible effects of acute and long-term administration of Δ−9-tetrahydrocannabinol (THC) on memory in the rat. Drug and Alcohol Dependence 28, 167175.CrossRefGoogle ScholarPubMed
Packard, MG, Knowlton, BJ (2002). Learning and memory functions of the basal ganglia. Annual Review of Neuroscience 25, 563593.CrossRefGoogle ScholarPubMed
Pencer, A, Addington, J (2003). Substance use and cognition in early psychosis. Journal of Psychiatry and Neuroscience 28, 4854.Google ScholarPubMed
Penk, WE, Flannery, RB Jr, Irvin, E, Geller, J, Fisher, W, Hanson, MA (2000). Characteristics of substance-abusing persons with schizophrenia: the paradox of the dually diagnosed. Journal of Addictive Diseases 19, 2330.CrossRefGoogle ScholarPubMed
Pertwee, RG (2008). Ligands that target cannabinoid receptors in the brain: from THC to anandamide and beyond. Addiction Biology 13, 147159.CrossRefGoogle ScholarPubMed
Pezdek, K, Evans, GW (1979). Visual and verbal memory for objects and their spatial locations. Journal of Experimental Psychology Human Learning and Memory 5, 360373.CrossRefGoogle ScholarPubMed
Pope, HG, Gruber, AJ, Hudson, JI, Cohane, G, Huestis, MA, Yurgelun-Todd, D (2003). Early-onset cannabis use and cognitive deficits: what is the nature of the association? Drug and Alcohol Dependence 69, 303310.CrossRefGoogle ScholarPubMed
Pope, HG, Gruber, AJ, Hudson, JI, Huestis, MA, Yurgelun-Todd, D (2001). Neuropsychological performance in long-term cannabis users. Archives of General Psychiatry 58, 909915.CrossRefGoogle ScholarPubMed
Potvin, S, Joyal, CC, Pelletier, J, Stip, E (2008). Contradictory cognitive capacities among substance-abusing patients with schizophrenia: a meta-analysis. Schizophrenia Research 100, 242251.CrossRefGoogle ScholarPubMed
Poulsen, HA, Sutherland, GJ (2000). The potency of cannabis in New Zealand from 1976 to 1996. Science and Justice 40, 171176.CrossRefGoogle ScholarPubMed
Rabin, RA, Zakzanis, KK, Daskalakis, ZJ, George, TP (2012). Effects of cannabis use status on cognitive function, in males with schizophrenia. Psychiatry Research 206, 158165.CrossRefGoogle ScholarPubMed
Rabin, RA, Zakzanis, KK, George, TP (2011). The effects of cannabis use on neurocognition in schizophrenia: a meta-analysis. Schizophrenia Research 128, 111116.CrossRefGoogle ScholarPubMed
Ranganathan, M, D'Souza, DC (2006). The acute effects of cannabinoids on memory in humans: a review. Psychopharmacology 188, 425444.CrossRefGoogle ScholarPubMed
Ruiz-Veguilla, M, Callado, LF, Ferrin, M (2012). Neurological soft signs in patients with psychosis and cannabis abuse: a systematic review and meta-analysis of paradox. Current Pharmaceutical Design 18, 51565164.CrossRefGoogle ScholarPubMed
Salyers, MP, Mueser, KT (2001). Social functioning, psychopathology, and medication side effects in relation to substance use and abuse in schizophrenia. Schizophrenia Research 48, 109123.CrossRefGoogle Scholar
Schnell, T, Koethe, D, Daumann, J, Gouzoulis-Mayfrank, E (2009). The role of cannabis in cognitive functioning of patients with schizophrenia. Psychopharmacology (Berlin) 205, 4552.CrossRefGoogle ScholarPubMed
Schoeler, T, Bhattacharyya, S (2013). The effect of cannabis use on memory function: an update. Journal of Substance Abuse and Rehabilitation 4, 1127.Google ScholarPubMed
Schreiner, AM, Dunn, ME (2012). Residual effects of cannabis use on neurocognitive performance after prolonged abstinence: a meta-analysis. Experimental and Clinical Psychopharmacology 20, 409420.CrossRefGoogle ScholarPubMed
Smith, K, Flatley, J (2011). Drug misuse declared: findings from the 2010/11 British Crime Survey England and Wales. Home Office Statistical Bulletin 12/11 ( Accessed August 2015.Google Scholar
Smith, MJ, Cobia, DJ, Wang, L, Alpert, KI, Cronenwett, WJ, Goldman, MB, Mamah, D, Barch, DM, Breiter, HC, Csernansky, JG (2014). Cannabis-related working memory deficits and associated subcortical morphological differences in healthy individuals and schizophrenia subjects. Schizophrenia Bulletin 40, 287299.CrossRefGoogle ScholarPubMed
Sneider, JT, Pope, HG Jr, Silveri, MM, Simpson, NS, Gruber, SA, Yurgelun-Todd, DA (2008). Differences in regional blood volume during a 28-day period of abstinence in chronic cannabis smokers. European Neuropsychopharmacology 18, 612619.CrossRefGoogle ScholarPubMed
Solowij, N, Battisti, R (2008). The chronic effects of cannabis on memory in humans: a review. Current Drug Abuse Reviews 1, 8198.CrossRefGoogle ScholarPubMed
Solowij, N, Pesa, N (2010). Cognitive abnormalities and cannabis use. Revista Brasileira de Psiquiatria 32 (Suppl. 1), S31S40.CrossRefGoogle ScholarPubMed
Song, F, Sheldon, TA, Sutton, AJ, Abrams, KR, Jones, DR (2001). Methods for exploring heterogeneity in meta-analysis. Evaluation and the Health Professions 24, 126151.CrossRefGoogle ScholarPubMed
Soueif, MI (1976). Differential association between chronic cannabis use and brain function deficits. Annals of the New York Academy of Sciences 282, 323343.CrossRefGoogle ScholarPubMed
Tait, RJ, Mackinnon, A, Christensen, H (2011). Cannabis use and cognitive function: 8-year trajectory in a young adult cohort. Addiction 106, 21952203.CrossRefGoogle Scholar
UN Office on Drugs and Crime (2010). World Drug Report 2010. United Nations Publications: New York.Google Scholar
Vakil, E, Blachstein, H (1997). Rey AVLT: developmental norms for adults and the sensitivity of different memory measures to age. Clinical Neuropsychologist 11, 356369.CrossRefGoogle Scholar
Viechtbauer, W (2010). Conducting meta-analyses in R with the metafor package. Journal of Statistical Software 36, 148.CrossRefGoogle Scholar
Wadsworth, EJK, Moss, SC, Simpson, SA, Smith, AP (2006). Cannabis use, cognitive performance and mood in a sample of workers. Journal of Psychopharmacology 20, 1423.CrossRefGoogle Scholar
Wagner, D, Becker, B, Gouzoulis-Mayfrank, E, Daumann, J (2010). Interactions between specific parameters of cannabis use and verbal memory. Progress in Neuro-Psychopharmacology and Biological Psychiatry 34, 871876.CrossRefGoogle ScholarPubMed
Wobrock, T, Falkai, P, Schneider-Axmann, T, Hasan, A, Galderisi, S, Davidson, M, Kahn, RS, Derks, EM, Boter, H, Rybakowski, JK (2013). Comorbid substance abuse in first-episode schizophrenia: effects on cognition and psychopathology in the EUFEST study. Schizophrenia Research 147, 132139.CrossRefGoogle ScholarPubMed
Wojtalik, JA, Barch, DM (2014). An fMRI study of the influence of a history of substance abuse on working memory-related brain activation in schizophrenia. Frontiers in Psychiatry 5, 1.CrossRefGoogle Scholar
Yücel, M, Bora, E, Lubman, DI, Solowij, N, Brewer, WJ, Cotton, SM, Conus, P, Takagi, MJ, Fornito, A, Wood, SJ (2012). 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 38, 316330.CrossRefGoogle Scholar
Yucel, M, Solowij, N, Respondek, C, Whittle, S, Fornito, A, Pantelis, C, Lubman, DI (2008). Regional brain abnormalities associated with long-term heavy cannabis use. Archives of General Psychiatry 65, 694701.CrossRefGoogle ScholarPubMed
Supplementary material: File

Schoeler supplementary material

Schoeler supplementary material 1

Download Schoeler supplementary material(File)
File 1 MB
Cited by

Send article to Kindle

To send this article to your Kindle, first ensure is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about sending to your Kindle. Find out more about sending to your Kindle.

Note you can select to send to either the or variations. ‘’ emails are free but can only be sent to your device when it is connected to wi-fi. ‘’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

Find out more about the Kindle Personal Document Service.

The effects of cannabis on memory function in users with and without a psychotic disorder: findings from a combined meta-analysis
Available formats

Send article to Dropbox

To send this article to your Dropbox account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Dropbox.

The effects of cannabis on memory function in users with and without a psychotic disorder: findings from a combined meta-analysis
Available formats

Send article to Google Drive

To send this article to your Google Drive account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Google Drive.

The effects of cannabis on memory function in users with and without a psychotic disorder: findings from a combined meta-analysis
Available formats

Reply to: Submit a response

Please enter your response.

Your details

Please enter a valid email address.

Conflicting interests

Do you have any conflicting interests? *