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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Available from: Jane Boydell
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    • "The magnitudes of the various symptom dimensions were very similar in the two groups. Most studies comparing cannabis users and non-users at the time of a first-psychotic episode or in a context of chronic schizophrenia did not evidence a relationship between cannabis use and symptoms[4,20,24,42,565758. A few studies have reported evidence of association with greater positive symptoms596061or lesser negative symptoms[23,62,63]. "
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    ABSTRACT: Background: A high prevalence of cannabis use disorder has been reported in subjects suffering from schizophrenia, fuelling intense debate about whether schizophrenia with pre-onset cannabis use disorder may be a distinct entity with specific features or whether cannabis use disorder can precipitate schizophrenia in genetically vulnerable subjects. Methods: We retrospectively assessed schizophrenia subjects with and without pre-onset cannabis use disorder on the basis of their clinical features, assessed categorically and dimensionally with the operational criteria checklist for psychotic illnesses (OCCPI). We also investigated whether the two groups could be differentiated on the basis of a history of psychiatric disorders in first-degree relatives. A principal component factor analysis of the OCCPI items was used to identify specific symptom dimensions. The relationships between symptom dimensions and cannabis status were analysed by point-biserial correlation analysis to control for sex and age at time of the assessment and illness duration. Results: One hundred and seventy-one subjects with a diagnosis of schizophrenia were included. Among them, forty-one patients (18.2 % of the sample) had a cannabis use disorder before or at the time of the onset of schizophrenia. We found similar results in symptoms patterns or family history between patients with and without pre-onset cannabis use disorder. Conclusions: Our results clearly argue against cannabis-associated schizophrenia being a relevant distinct clinical entity of schizophrenia with specific features.
    Full-text · Article · Dec 2015 · Annals of General Psychiatry
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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.
    Full-text · Article · May 2011 · Schizophrenia Research
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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.
    Full-text · Article · Dec 2010 · Schizophrenia Research
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