مصرف کانابیس، شناخت و ساختار مغز در روان پریشی اپیزود اول

Cannabis use is highly prevalent worldwide and it is associated with psychosis, but its effects on brain structure and cognition are still controversial. The aim of this paper is to investigate cognitive functioning and brain structure in patients with their first episode of psychosis who used Cannabis. We examined gray matter and lateral ventricle volumes in 28 patients with first-episode psychosis and a history of Cannabis use, 78 patients without a history of Cannabis use and 80 healthy controls who had not used Cannabis. Cognition was assessed using forward and backwards digit span tests, from the Wechsler Memory Scale-Third Edition (WMS-III) and the Controlled Oral Word Association Test (COWAT). Patients with a history of Cannabis use had less brain abnormalities, characterized by gray matter and lateral ventricle volume preservation, as well as less attentional and executive impairments compared to patients without a history of Cannabis use. Cannabis-using patients who develop psychosis have less neurodevelopmental impairment and better cognitive reserve than other psychotic patients; perhaps reflecting different etiological processes.

Cannabis is the most widely used illegal substance worldwide and its use is associated with increased risk of psychosis ( Moore et al., 2007, Murray et al., 2007, Koskinen et al., 2010 and UNODC, United Nations Office on Drugs and Crime, 2011). However, studies about Cannabis effects on human brain structure have provided heterogeneous and inconclusive data ( Block et al., 2000, Matochik et al., 2005, Tzilos et al., 2005, Jager et al., 2007, Szeszko et al., 2007, Yücel et al., 2008, Wobrock et al., 2009, Lorenzetti et al., 2010, Martín-Santos et al., 2010, Cousijn et al., 2012, Malchow et al., 2012 and Rapp et al., 2012). Our previous data from a population-based voxel-based morphometry (VBM) study examining patients with first-episode psychosis (FEP), including Cannabis users and non-users, showed significant regional gray matter (GM) deficits, lateral ventricle (LV) enlargement, midline brain abnormalities and poorer cognitive functioning in patients ( Ayres et al., 2007, Schaufelberger et al., 2007, Minatogawa-Chang et al., 2009, Ayres et al., 2010, Rosa et al., 2010, Trzesniak et al., 2012 and Schaufelberger et al., 2011). Although Cannabis use is known to be associated with cognitive dysfunction and brain abnormalities in non-psychotic people ( Hester et al., 2009, Cunha et al., 2010, Fontes et al., 2011a, Fontes et al., 2011b and Solowij et al., 2012), there is evidence that Cannabis is associated with better premorbid cognitive functioning in people with schizophrenia ( Rodríguez-Sánchez et al., 2010 and Yücel et al., 2012) and bipolar disorder ( Braga et al., 2012). However, only one study (without a control group) has investigated the relationship between Cannabis use, brain structure and cognitive functioning in patients with FEP to date ( Schnell et al., 2012). In the present study, we investigated GM and LV volumes, as well as cognitive performance in patients with FEP and a history of Cannabis use (FEP C +), FEP without any history of Cannabis use (FEP C −), and healthy controls (HC). Based on previous neuropsychological findings, we hypothesized that subjects with FEP C + would present less structural brain abnormalities and a more preserved pattern of cognitive functioning than patients with FEP C −.