Exploring the relationship between frequent cannabis use, vocal changes and language use

Background Cannabis use is prevalent among individuals with psychosis and a significant risk factor for the development of psychotic disorders, leading to unfavorable outcomes. Speech changes are frequently examined in psychotic disorders and connected to clinical outcomes. However, limited research investigated the impact of cannabis use on speech, which could potentially be a crucial confounding factor in the observed speech changes associated with psychosis. This study explores the differences in speech between frequent cannabis users and matched non-users. Methods Eight-minute speech samples from frequent cannabis users (N=82) and non-users (N=82) matched for gender, age, and education were manually transcribed and analyzed. Differences in vocal, semantic, and speech connectivity features were examined using T-tests. Logistic regression and random forest classifiers were employed to evaluate the discriminatory power of speech features. Results Acoustic, semantic and connectivity measures of speech showed significant differences between groups. Frequent cannabis users exhibited more voice breaks and back vowels. Connectivity analysis revealed more one-word loops in the cannabis group. Frequent users used more words, spoke coherently, and stayed on topic. Using logistic regression and random forest classifiers, participants were classified into cannabis or non-user groups with 0.66 / 0.72 accuracy (AUC = 0.62 / 0.69) based on demographic information and speech features. Conclusions Cannabis use is associated with alterations in speech features that overlap with those observed in psychosis. Consequently, understanding and potentially accounting for the effects of cannabis use on speech would be crucial for facilitating the treatment of psychotic disorders through speech analysis.