Mhalla A, et al. – The study aimed to determine the association between neurological soft signs (NSS) and cannabis use, an environmental risk factor of psychosis. The data presented in this work showed a negative correlation between cannabis use and NSS, particularly regarding motor discoordination. This finding supported the hypothesis that a strong environmental risk factor, such as cannabis, might contribute to the onset of psychosis even in the presence of lower biological and genetic vulnerability, as reflected indirectly by lower NSS scores.

Methods

• It was a cross-sectional study.
• This investigation was done on consecutively admitted patients hospitalized for first-episode psychosis.
• After that, NSS were surveyed by the NSS scale (23 items exploring motor coordination, motor integrative function, sensory integration, involuntary movements or posture, quality of lateralization).
• Presence of NSS was characterized as a NSS scale total score ≥9.5.
• Finally, cannabis use was ascertained with the cannabis subsection in the Composite International Diagnostic Interview.

Results

• The prevalence of current cannabis use was 14.8% (heavy use = 8.2%, occasional use = 6.6%) among 61 first-episode psychosis patients (mean age = 28.9 ± 9.4 years; male = 86.9%, antipsychotic-naïve = 75.4%).
• It was observed in the findings that NSS were present in 83.6% of the sample (cannabis users = 66.7% versus cannabis non-users = 85.5%, p = 0.16).
• It was noted that the mean total NSS score was 15.3 ± 6.7, with a significant lower total NSS score in cannabis users (11.2 ± 5.6 versus 16.0 ± 6.7, p = 0.048).
• However, differences were strongest for the “motor coordination” (p = 0.06) and “involuntary movements” (p = 0.07) sub-scores.