Variable individual sensitivity to cannabis in patients with schizophrenia (original) (raw)
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Cannabis and schizophrenia: impact on onset, course, psychopathology and outcomes
European Archives of Psychiatry and Clinical Neuroscience, 2002
s Abstract Cannabis consuming schizophrenic patients are younger at onset, are likely to have started abuse before onset of schizophrenia and show more prominent positive symptoms than nonabusers. It has been suggested that cannabis is a risk-factor for schizophrenia. Our aim was to assess prevalence and pattern of cannabis use in 125 chronic male schizophrenic subjects and its impact on socioepidemiological and clinical variables as well as which disorder precedes the other in onset. Assessment of consumption was made with a semi-structured clinical interview. Clinical status was assessed by means of the SANS, SAPS, PANSS and BPRS scales. Cannabis consumption was found in 54 subjects (43 %), 66.7 % of whom started it at least three years before onset of schizophrenia. Consumers were younger and with lower negative symptoms, specially abusers and polysubstance abusers. Family history positive for psychosis was more frequent in consumers, especially when consumption started before onset of schizophrenia. Subjects whose onset of schizophrenia preceded the beginning of cannabis abuse had more positive symptoms than those who started abuse before the onset of schizophrenia. On these grounds, our sample could be subdivided into two main groups, one that uses substances to counter distressing symptoms of schizophrenia and another in which cannabis might be one of the factors predisposing to the disease; the former had less negative symptoms than nonabusers. Our data support both heterogeneity of schizophrenia and genetic susceptibility to environmental agents. s
Cannabis use and the risk of later schizophrenia: a review
Addiction, 2004
To study the role of cannabis use in the onset of symptoms and disorders in the schizophrenia spectrum. Design Review of five population-based, longitudinal studies on the relationship between cannabis use and problems ranging from the experience of psychotic symptoms to hospitalization with a confirmed diagnosis of schizophrenia. Several hypotheses are examined that may explain this relationship:
Cannabis consumption and psychosis or schizophrenia development
International Journal of Social Psychiatry, 2018
Objective: Cannabis consumption produces psychopathology, in some cases psychotic episodes, which are of our interest in this work. However, the relationship between cannabis use and psychosis has not been fully elucidated. The objectives of this work are to (1) review the current state of knowledge on the association of cannabis use with the risk of the development of psychosis or psychotic symptoms in people without schizophrenia and (2) assess the consistency of the hypothesis that cannabis use is associated with increased risk of psychosis in people without schizophrenia. Method: This work included research done in humans until May 2018 with the keywords ‘cannabis’ and ‘psychosis’, published in English and Spanish, in the PubMed database. Results: In all, 66 papers were analyzed, of which 23 were cohort trials and 43 were reviews. Conclusion: Cannabis use doubles the risk of developing psychosis in vulnerable people. There even exists a relationship regarding the dose used and t...
Cannabis use and genetic predisposition for schizophrenia: a case-control study
Psychological Medicine, 2008
BackgroundCannabis use may be a risk factor for schizophrenia. Part of this association may be explained by genotype–environment interaction, and part of it by genotype–environment correlation. The latter issue has not been explored. We investigated whether cannabis use is associated with schizophrenia, and whether gene–environment correlation contributes to this association, by examining the prevalence of cannabis use in groups with different levels of genetic predisposition for schizophrenia.MethodCase-control study of first-episode schizophrenia. Cases included all non-Western immigrants who made first contact with a physician for schizophrenia in The Hague, The Netherlands, between October 2000 and July 2005 (n=100; highest genetic predisposition). Two matched control groups were recruited, one among siblings of the cases (n=63; intermediate genetic predisposition) and one among immigrants who made contact with non-psychiatric secondary health-care services (n=100; lowest geneti...
Schizophrenia Research, 2010
Introduction-The purpose of this study is to determine if an earlier age at onset of positive symptoms in schizophrenia is associated with cannabis use disorders (CUD). Methods-49 first-episode schizophrenia subjects with CUD were compared to 51 first-episode schizophrenia subjects with no substance use disorders for demographic and clinical variables. A multivariate logistic regression was performed to determine the joint relationship between variables significantly associated with CUD on univariate testing and ascertain if these variables independently predict CUD. Significance level was set at p<0.05. Results-74% of CUD subjects had the onset of CUD before the onset of positive symptoms. Compared to non-substance abusing subjects, CUD subjects were predominantly male, younger at study entry, had an earlier age at onset of positive symptoms, less educational attainment, a lower own socioeconomic status, better premorbid childhood social adjustment, a trend for poorer premorbid childhood academic adjustment, less motor abnormalities but more severe hallucinations and delusions. In the multivariate analysis, only male gender, worse socioeconomic status, better premorbid childhood social adjustment, and more severe positive symptoms at study entry were associated with a lifetime history of CUD. Discussion-although cannabis use precedes the onset of illness in most patients, there was no significant association between onset of illness and CUD that was not accounted by demographic and clinical variables. Previous studies implicating CUD in the onset of schizophrenia may need to more comprehensively assess the relationship between CUD and schizophrenia, and take into account additional variables that we found associated with CUD.
Schizophrenia Research, 2007
Background: There is considerable interest in cannabis use in psychosis. It has been suggested that the chronic psychosis associated with cannabis use, is symptomatically distinct from idiopathic schizophrenia. Several studies have reported differences in psychopathology and family history in people with schizophrenia according to whether or not they were cannabis users. We set out to test the hypotheses arising from these studies that cannabis use is associated with more bizarre behaviour, more thought disorder, fewer negative symptoms including blunted affect, more delusions of reference, more paranoid delusions and a stronger family history of schizophrenia. Method: We used a case register that contained 757 cases of first onset schizophrenia, 182 (24%) of whom had used cannabis in the year prior to first presentation, 552 (73%) had not and 3% had missing data. We completed the OPCRIT checklist on all patients and investigated differences in the proportion of people with distractibility, bizarre behaviour, positive formal thought disorder, delusions of reference, well organised delusions, any first rank symptom, persecutory delusions, abusive/accusatory hallucinations, blunted affect, negative thought disorder, any negative symptoms (catatonia, blunted affect, negative thought disorder, or deterioration), lack of insight, suicidal ideation and a positive family history of schizophrenia, using chi square tests. Logistic regression modelling was then used to determine whether prior cannabis use affected the presence of the characteristics after controlling for age, sex and ethnicity. Results: There was no statistically significant effect of cannabis use on the presence of any of the above. There remained however a non-significant trend towards more insight (OR 0.65 p = 0.055 for "loss of insight") and a finding of fewer abusive or accusatory hallucinations (OR 0.65 p = 0.049) of borderline significance amongst the cannabis users. These were in the hypothesised direction. There was no evidence of fewer negative symptoms or greater family history amongst cannabis users. Conclusion: We found few appreciable differences in symptomatology between schizophrenic patients who were or were not cannabis users. There were no differences in the proportion of people with a positive family history of schizophrenia between cannabis users and non-users. This argues against a distinct schizophrenia-like psychosis caused by cannabis.
Cannabis Use and Psychosis: Theme Introduction
Current Pharmaceutical Design, 2012
Cannabis is among the most widely used illicit substances. Epidemiological and neuroscientific evidence, though poorly integrated, have established a strong association between cannabis use and increased risk of psychosis. Chronic cannabis use, especially of new synthetic varieties, may trigger psychosis and precipitate schizophrenia in vulnerable individuals. However, the specific pathways by which cannabis affects brain function are unclear. It seems likely that a complex genetic-environmental interaction may underlie the link between cannabis exposure and psychosis onset, with multiple genetic variations and several environmental factors (i.e., trauma or maltreatment during childhood) involved. Also, the possible role of basic symptoms in cannabis users is still not fully acknowledged. Basic symptoms may possibly be a marker for the development of full schizophrenia in cannabis users and their recognition may play a role in prevention strategies. Moreover, the differential impact of different types of cannabis has been generally overlooked and little is known about possible pharmacological treatment approaches (with antipsychotics, cannabis agonists, cannabis antagonists) for cannabis users at risk of psychosis. The aim of the present review is to open this issue with a broad introduction on the clinical and pathophysiological link between cannabis abuse and psychosis onset.
Cannabis use and age of diagnosis of schizophrenia
European Psychiatry, 2009
Background and objectivesObservational studies have reported earlier onset of psychosis in schizophrenic patients with a history of cannabis use. Earlier age of onset of schizophrenia has been associated with a poorer outcome. We aimed to examine whether cannabis use determined an earlier onset of schizophrenia in a sample of first episode patients, in an area with one of Europe's highest rates of cannabis use.Methods116 subjects with first episode psychosis and subsequent diagnosis of schizophrenia (after a 12-month follow-up) were included Age at first antipsychotic treatment (A1T) was used as proxy for age of psychosis onset, and acted as dependent variable for the statistical analysis. Cannabis use was evaluated retrospectively, and divided into three groups according to peak frequency (never, sporadic/frequent, daily).Results46 (39.7%) subjects had never used cannabis, 23 (19.9%) had done so sporadically/frequently, and 47 (40.5%) daily. A1T differed between the three group...
Cannabis use and psychosis: the origins and implications of an association
Advances in Psychiatric Treatment, 2007
Evidence for the effectiveness of treatment or secondary prevention of psychotic illness such as schizophrenia is often disappointing. This situation reflects our limited understanding of the aetiology of psychosis. There is good evidence that both genetic and environmental factors are implicated but the precise identity of these is unclear. Cannabis use is one candidate as a possible, modifiable environmental influence on both incidence and prognosis of psychosis. Evidence supporting this candidature is exclusively observational, and its strength has perhaps been overestimated and problems related to its interpretation underestimated by some. Nevertheless the possibility that cannabis does cause psychosis remains. Because of this, and because there are other good public health reasons to prevent cannabis use, interventions targeting use need to be evaluated. This evaluation, along with other imaginative approaches to future research, is needed to further our understanding of the de...
Marijuana use and the risk of schizophrenia
To review the literature on the association between cannabis use as a triggering factor for schizophrenia in individuals with a predisposition to psychosis who used cannabis and to verify the relationship with the pathogenesis. I.