Reduced Cortical Cannabinoid 1 Receptor Messenger RNA and Protein Expression in Schizophrenia

Abstract

A growing body of evidence suggests that alterations in cannabinoid signaling in the brain contribute to the pathophysiological findings of schizophrenia. For instance, markers of endogenous cannabinoids^1-3 and the principal cannabinoid receptor in the brain (cannabinoid 1 receptor [CB1R])^4-6 have been reported to be altered in schizophrenia. Convergent findings from epidemiological studies suggest that cannabis use represents a substantial environmental risk factor for schizophrenia, especially when exposure occurs during adolescence.^7,8 Cannabis use is also associated with a poorer outcome, more frequent hospitalizations, and increased severity of symptoms, especially cognitive impairments, in individuals with schizophrenia.^9-12 Finally, long-term users of cannabis exhibit deficits in cognitive functions, such as working memory,¹³ that are impaired in schizophrenia.¹⁴