Cannabis use patterns and psychotic-like experiences: a cross-sectional study of heavy users, occasional users, and non-users

Background: The relationship between cannabis use and psychotic-like experiences (PLEs) remains a crucial area of investigation, particularly regarding different consumption patterns. Methods: This cross-sectional study examined 150 participants divided into three groups: heavy cannabis users (n = 43), occasional users (n = 47), and non-users (n = 60). Participants were classified using CUDIT-R scores combined with self-reported frequency of use. Assessments included the Community Assessment of Psychic Experiences (CAPE) scale, Global Assessment of Functioning (GAF), and Clinical Global Impression (CGI) scales. Cannabis use patterns, age of onset, and duration were documented. Results: Heavy users (mean age 23.6 ± 4.9 years) showed significantly higher scores on positive symptoms (38.4 ± 6.2) compared to occasional users (28.6 ± 5.4) and non-users (18.2 ± 4.2; p < 0.01; η2p = 0.24). Depressive symptoms were also elevated in heavy users (18.6 ± 3.8) versus occasional users (15.4 ± 3.2) and non-users (12.2 ± 2.8; p < 0.01; η2p = 0.19). No significant differences were found in negative symptoms across groups (p = 0.24; η2p = 0.02). Earlier age of onset (<16.4 years) correlated with increased PLEs (r = 0.27, p < 0.05) and poorer functioning. Heavy users demonstrated strong correlations between cannabis use frequency and both positive symptoms (r = 0.58, p < 0.01) and depressive symptoms (r = 0.52, p < 0.01). Conclusions: The findings suggest a frequency-related association between cannabis use and PLEs, particularly for positive and depressive symptoms. Early onset of use appears to be a significant risk factor for developing psychotic-like experiences, while negative symptoms remain largely unaffected. These results highlight the importance of considering consumption patterns when assessing the psychological impact of cannabis use.