A comparison of symptoms and family history in schizophrenia with and without prior Cannabis use: implications for the concept of Cannabis psychosis

Division of Psychological Medicine, PO Box 63, Institute of Psychiatry, De Crespigny Park, Denmark Hill, London, SE5 8AF, United Kingdom.
Schizophrenia Research (Impact Factor: 3.92). 08/2007; 93(1-3):203-10. DOI: 10.1016/j.schres.2007.03.014
Source: PubMed


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.

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    • "j o u r n a l h o m e p a g e : w w w. e l s ev i e r. c o m / l o c a t e / s c h r e s 2004; Veen et al., 2004; Dubertret et al., 2006; Boydell et al., 2007; Selten et al., 2007). To complicate things further, recent studies showed that cognitive functions were preserved or even improved in cannabis using schizophrenic patients (Coulston et al., 2007; Jockers-Scherubl et al., 2007; Sevy et al., 2007; Potvin et al., 2008; Schnell et al., 2009; Yucel et al., 2010). "
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    ABSTRACT: INTRODUCTION: A number of studies indicate a higher risk for psychosis as well as for neurocognitive deficits in healthy cannabis users. However, little is known about the impact of cannabis use on outcome in schizophrenia. In fact, there is growing evidence that cannabis-using schizophrenic patients may show preserved or even better neurocognitive performance compared to schizophrenic non-users. METHODS: We measured mismatch negativity (MMN) to investigate preattentional neurocognitive functioning in long-term abstinent chronic cannabis users with (SZCA n=27) and without schizophrenia (COCA n=32) compared to schizophrenic patients (SZ n=26) and healthy controls (CO n=34) without any chronic drug use. RESULTS: Healthy cannabis users showed reduced frontal MMN compared to controls (p=0.036). In contrast, cannabis-using schizophrenic patients showed increased frontal MMN compared to schizophrenic patients without cannabis use (p=0.038). Comparing non-cannabis users, schizophrenic patients showed reduced frontal MMN (p=0.001). No significant differences were found between CO and SZCA (p=0.27), and COCA and SZCA (p=0.50). CONCLUSION: Results suggest that chronic cannabis use may have different effects on preattentional neurocognitive functioning in schizophrenic patients when compared to healthy subjects. This may be related to preexisting differences in the endocannabinoid system between schizophrenic patients and healthy subjects. However, due to the naturalistic design of the study, the results must be interpreted with caution.
    Schizophrenia Research 05/2011; 130(1-3):222-7. DOI:10.1016/j.schres.2011.05.011 · 3.92 Impact Factor
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    • "The 74 OPCRIT items (McGuffin et al., 1991) rated for the first year after presentation were used as the main source of clinical risk factor variables. In addition, lifetime diagnosis of cannabis abuse prior to presentation was rated from the case notes as absent, present or not known (Boydell et al., 2007). In total, twenty risk factors were selected from these variables (based on a review of the existing literature), comprising six sociodemographic factors (gender, ethnicity, broad RDC diagnosis, age at onset, relationship status and unemployment), ten factors related to symptoms and clinical presentation (poor premorbid social adjustment, difficult rapport, persecutory delusions, grandiose delusions , delusions of passivity, any auditory hallucination, reckless activity, dysphoria, suicidal ideation and family history of psychosis) and four factors which were related to drug misuse, function and insight (lifetime diagnosis of alcohol/other drug abuse, lifetime diagnosis of cannabis abuse, deterioration from premorbid level of functioning and lack of insight). "
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    ABSTRACT: Much remains unknown about whether there are early risk factors for suicide in psychosis. The aim of the study was to determine whether there are any identifiable early symptom clusters, aetiological factors or illness course markers for suicide in first episode psychosis. A total of 2132 patients with first episode psychosis presenting to secondary care services in London (1965-2004; n=1474), Nottingham (1997-1999; n=195) and Dumfries and Galloway (1979-1998; n=463) were traced after up to 40 years (mean 13 years) following first presentation. Risk factors were identified from the Operational Checklist for Psychotic Disorders rated for the first year following presentation. Overall, there were 51 suicides and 373 deaths from other causes. Male gender (RR 2.84, 95% CI 1.20-6.69, p=0.02) and a cumulative threshold effect of symptoms early in the illness (RR 6.81, 95% CI 2.33-19.85, p<0.001) were associated with a higher propensity for later completed suicide. There was also a suggestion that early manic symptoms might increase the risk of later suicide irrespective of initial diagnosis. Suicide risk was associated with a cumulative threshold effect of symptoms and manic symptoms. As suicide is a relatively rare event in psychotic disorders, general population-based prevention strategies may have more impact in this vulnerable group as well as the wider population.
    Schizophrenia Research 12/2010; 126(1-3):11-9. DOI:10.1016/j.schres.2010.11.021 · 3.92 Impact Factor
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    • "Comparison of symptoms of chronic psychosis with and without cannabis abuse resulted in conflicting data. While certain results suggested no difference between the two subgroups, others showed that cannabis dependent had less positive thought disorder and fewer negative symptoms (Bersani et al., 2002; Buhler et al., 2002; Boydell et al., 2007). Soyka et al. (2001) reported that patients with current cannabis use had more incoherence, more delusions of reference, fewer delusions of guilt, more visual hallucinations, more First Rank symptoms and less insight (Soyka et al., 2001). "
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    ABSTRACT: Although incidence of schizophrenia is higher among cannabis users and marijuana is the most common abused drug by adolescents, etiological linkage between schizophrenia and cannabis use is still not clarified. Clinical experiences suggest that regular cannabis user can show similar psychotic episode to schizophrenic disorders but it is still unclear if chronic cannabis use with schizophreniform disorder is a distinct entity requiring special therapy or it can be treated as classical schizophrenia. There are no data available on the comparison of pharmacotherapy between schizophreniform patients with and without cannabis use.
    Progress in Neuro-Psychopharmacology and Biological Psychiatry 11/2010; 35(1):212-7. DOI:10.1016/j.pnpbp.2010.11.007 · 3.69 Impact Factor
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