The neuropsychological profiles of young psychosis patients with and without current cannabis use

Does cannabis affect cognitive functioning in patients with schizophrenia?

Introduction

Cannabis use impairs cognitive performance in healthy subjects; several studies have shown improved cognitive outcomes in schizophrenic patients using cannabis. The aim of this study was to evaluate the effects of cannabis use on cognitive function in Moroccan patients with schizophrenia who were cannabis users.

Method

Two groups were recruited in a Moroccan University Psychiatric Centre. Fifty patients diagnosed with schizophrenia according to the DSM-V who were cannabis users (SZ CANN +) and forty-nine patients diagnosed with schizophrenia according to DSM-V who do not use cannabis (SZ CANN-). Cognitive functioning was assessed using the CogState neuropsychological battery.

Results

The results of the study suggest that SZ CANN- patients performed better in the test of psychomotor function, attention and verbal memory. While SZ CANN+ patients performed better in the test of working memory, visual memory and emotional recognition. We found no relationship between SZ CANN+ patients and SZ CANN- patients concerning executive function.

Conclusions

Our results suggest that cannabis use may have different effects on neurocognitive functioning. It is associated with disorders of psychomotor function, attention and verbal memory. So, it is associated with an improvement in working memory, visual memory and emotion recognition.

Using Task-fMRI to Explore the Relationship Between Lifetime Cannabis Use and Cognitive Control in Individuals With First-Episode Schizophrenia

While continued cannabis use and misuse in individuals with schizophrenia is associated with a variety of negative outcomes, individuals with a history of use tend to show higher cognitive performance compared to non-users. While this is replicated in the literature, few studies have used task-based functional magnetic resonance imaging (fMRI) to evaluate whether the brain networks underpinning these cognitive features are similarly impacted. Forty-eight first-episode individuals with schizophrenia (FES) with a history of cannabis use (FES + CAN), 28 FES individuals with no history of cannabis use (FES-CAN), and 59 controls (CON) performed the AX-Continuous Performance Task during fMRI. FES+CAN showed higher cognitive control performance (d'-context) compared to FES-CAN (P < .05, ηp 2 = 0.053), and both FES+CAN (P < .05, ηp 2 = 0.049) and FES-CAN (P < .001, ηp 2 = 0.216) showed lower performance compared to CON. FES+CAN (P < .05, ηp 2 = 0.055) and CON (P < 0.05, ηp 2 = 0.058) showed higher dorsolateral prefrontal cortex (DLPFC) activation during the task compared to FES-CAN, while FES+CAN and CON were not significantly different. Within the FES+CAN group, the younger age of initiation of cannabis use was associated with lower IQ and lower global functioning. More frequent use was also associated with higher reality distortion symptoms at the time of the scan. These data are consistent with previous literature suggesting that individuals with schizophrenia and a history of cannabis use have higher cognitive control performance. For the first time, we also reveal that FES+CAN have higher DLPFC brain activity during cognitive control compared to FES-CAN. Several possible explanations for these findings are discussed.

Cognitive functioning in first episode psychosis. Gender differences and relation with clinical variables

AIMS

to study the differences in cognitive functioning in patients and controls. In addition, study the influence of symptoms, cannabis consumption, chlorpromazine doses, DUP and IQ in cognitive performance in patients, both in the total sample and divided by gender.

METHODS

70 first episode psychosis patients and 63 healthy controls (HC) participated in the study and were assessed with the MATRICS battery and the Vocabulary subtest of WAIS-IV. Symptoms in FEP patients were evaluated with the Emsley factors of the PANSS scale.

RESULTS

patients showed lower scores than controls in all cognitive domains studied. There were no significant differences between FEP men and FEP women, but we found gender differences in favour of women in processing speed, working memory and composite total scored domains in the HC group. Finally, symptoms and Chlorpromazine doses showed an influence on cognitive performance in the total FEP sample. When splitting the sample by gender, positive symptoms may be more detrimental to women's cognitive functioning, while disorganized symptoms may play the most important role in cognitive performance in men.

CONCLUSIONS

patients showed worse cognitive performance in all cognitive domains compared to healthy controls. In our FEP sample, gender does not seem to influence cognitive performance measured with the MATRICS. Severity of symptoms influences positively in cognitive performance. The dose of Chlorpromazine and symptoms are influential variables to be taken into account in cognition rehabilitation programs.