Examining the Relationship Between Schizophrenia and Cannabis Use: A Research Protocol

Abstract

Schizophrenia is a complex mental disorder depicted through positive and negative symptoms that interfere with daily functioning (Cornblatt et al., 1985; Liu et al., 2020). Schizophrenia is characterized by an insidious loss in brain function in the dorsal lateral prefrontal cortex, a region which precipitates interference of perceptions, thought processes, and emotional affect (National Institute of Health, 2024). This proposed study aims to investigate the longitudinal effects of high potency cannabis use and the development of schizophrenia symptoms over a period of 5 years. Utilizing a cross cross-sequential approach, adolescent participants n = 200, ages 13-19 will be recruited from the community and self-report strains of cannabis consumed, frequency of usage, and fluctuations in mood and perceptions. Assessments will be conducted at baseline and after 5 years using standardized measures including the Positive and Negative Syndrome Scale (PANNS), Brief Negative Symptom Scale (BNSS), and Addenbrooke’s Cognitive Examination-III (ACE-III). Anticipated results include a dose-dependent relationship, with higher levels of psychosis reported in the high potency cannabis group. Additionally, participants in the high potency group are expected to demonstrate higher scores on the psychometric tests used for assessing schizophrenia symptoms, as well as show signs of cognitive decline when compared to the low dose and control groups. These findings will contribute to the understanding of the long-term effects of cannabis use in adolescents and inform prevention strategies for the prodromal period of schizophrenia.