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08-07-2010 | Mental health | Article

Age at psychosis onset not influenced by cannabis use disorders


Free abstract

MedWire News: Cannabis use disorders (CUD) do not appear to influence age at onset of psychosis, although they do often precede the onset of illness, researchers report.

They found that any association between cannabis use disorder and onset of psychosis could be accounted for by demographic and clinical variables.

"Previous studies implicating CUD in schizophrenia may need to more comprehensively assess the relationship between CUD and schizophrenia, and take into account the additional variables that we found associated with CUD," say Serge Sevy, from The Zucker Hillside Hospital in Glen Oaks, New York, USA, and team.

They compared demographic and clinical variables in 49 first-episode schizophrenia patients with CUD and 51 first-episode schizophrenia patients without CUD.

Most (74%) of the patients with CUD had the onset of CUD before the onset of positive symptoms.

Schizophrenia patients with CUD, compared with their non-substance abusing counterparts, were predominantly male (82% vs 57%) and had an earlier age at onset of psychosis (20 vs 22 years). They also had less educational attainment, lower subject socioeconomic status, better premorbid childhood social adjustment (average score of 1.5 vs 2.1 on the Premorbid Adjustment Scale), and a trend for poorer premorbid childhood academic adjustment.

They also had fewer motor abnormalities but more severe hallucinations and delusions. The two groups did not differ, however, with regard to cognitive functioning.

On multivariate analysis, the only independent risk factors associated with CUD were being male, which increased the risk four fold, worse socioeconomic status (odds ratio [OR]=3.09), better premorbid childhood social adjustment (OR=0.52 based on average score of 1.5 vs 2.1), and more severe positive symptoms at study entry (OR=2.77).

"Although the onset of CUD preceded the onset of illness in most patients, our findings suggest that age at onset of psychosis was not associated with CUD," the researchers conclude in the journal Schizophrenia Research.

They note, however, that their multivariate logistic regression model only explained 32% of the variation associated with CUD, and therefore call for further studies to investigate other factors that may be associated, "such as neurodevelopmental abnormalities and psychiatric symptoms in childhood."

MedWire ( is an independent clinical news service provided by Current Medicine Group, a trading division of Springer Healthcare Limited. © Springer Healthcare Ltd; 2010

By Lucy Piper

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