Biological aspects of cannabis consumption in schizophrenia

Schizophrenia and psychotic disorders are major health issues with particular implications for both the individual and the medical system. Epidemiological data show a more frequent consumption of drugs in schizophrenic patients when compared to the general population. Studies have shown that the abuse of substances is the most common comorbidity associated with schizophrenia. Among illicit substances, cannabis is the most commonly encountered among patients with schizophrenia. Similar clinical features of schizophrenia and cannabis consumption could be explained by some common neurobiological implications. N-methyl-D-aspartate (NMDA) receptor stimulation is associated with psychotic-type phenomena and schizophrenia and NMDA receptors are involved in the clinical effects of cannabis consumption. Thus, the CB1 receptors that are spread mainly at the level of the NMDA secretory neurons are activated by tetrahydrocannabinol, the psychoactive component of cannabis. Moreover, cannabis abuse in association with other factors may contribute in triggering schizophrenia. Therefore, patients diagnosed with schizophrenia that abuse substances such as cannabis could represent a special category of patients that require a complex therapeutic approach, especially considering the multiple problems implicated, such as reduced compliance with treatment, unfavorable evolution and prognosis with multiple relapses and frequent hospitalizations