Cognitive performance and lifetime cannabis use in patients with first-episode schizophrenia spectrum disorder

Abstract

Introduction: Cognitive impairment is among the core features of schizophrenia. In a healthy population, the cognitive deficit is often linked with cannabis abuse, and although the same would be expected in patients with schizophrenia, research has presented contradictory results. Methods: Participants were patients with first-episode schizophrenia (FES) spectrum disorder who had been lifetime cannabis users (N = 30), FES non-users (N = 53) as well as healthy controls (HC) also divided into cannabis users (N = 20) and non-users (N = 49). All participants underwent an extensive neurocognitive assessment and filled in a cannabis questionnaire, which allowed for a comparison of the four groups on cognitive functioning. Results: FES patients using cannabis showed less impaired cognitive functioning with the most prominent difference in visual memory compared to FES non-users. However, they differed neither in the clinical assessment of general psychopathology, positive and negative symptoms, nor in medication from the patient's non-users. A comparison of the HC who used cannabis, and those who did not, revealed no sizeable differences in cognitive performance between the groups. Conclusions: The results delivered supporting evidence for the trend of superior neurocognitive performance in FES patients with a lifetime history of cannabis use compared to non-using patients.

Association between cannabis use and symptom dimensions in schizophrenia spectrum disorders: an individual participant data meta-analysis on 3053 individuals

“…The first sensitivity analysis excluded one dataset from the main analysis. 52 Indeed, the description of the cannabis-using group differed somewhat from the a priori criteria established in the protocol. Cannabis-users were defined as using cannabis with a frequency of at least a few times per year for several years (>2 years) or daily for more than one month prior to the onset of the disorder.…”

“…The overall risk of bias was considered low: 2 studies were judged as of “poor” quality in the context of the current study, 39 , 52 that of 8 as “fair”, 37 , 47 , 49 , 53 , 54 , 55 , 56 , 58 and that of 7 as “good” 45 , 46 , 48 , 50 , 51 , 57 , 59 (detailed rating in Appendix , Table S3, p.5 ). A risk for publication bias was found at the visual inspection of the funnel plot and the Egger's test for the positive dimension of both 3 and 5-factor PANSS ( Appendix , Figures [S2–S5], p.6–8 ).…”

Smoking and attention in schizophrenia spectrum disorders: What are we neglecting?

“…This could conceivably mask smoking-related benefits in visual attention tasks, such as the CPT. It may also be interesting to consider participants’ use of other substances that could affect visual attention, such as cannabis ( Hájková et al, 2021 ; Setién-Suero et al, 2022 ).…”

“…This study analyzed data from the clinical and neuropsychological assessments conducted within the project. Additional neuropsychological results from the ESO project were described in, e.g., Rodriguez et al (2019) , Hájková et al (2021) , and Rodriguez et al (2022) . The ESO study conformed to the ethical standards described in the latest version of the Declaration of Helsinki, and was approved by the NIMH-CZ Research Ethics Board (protocol number: 127/17).…”