Risk factors for cannabis use disorders and cannabis psychosis in Japan: Second report of a survey on cannabis‐related health problems among community cannabis users using social networking services

AIM: To determine the risk factors for cannabis use disorders and cannabis psychosis in Japan based on a 2021 online survey among Japanese users of social network services. METHODS: The 3142 respondents who had used cannabis within the preceding year were categorized into two groups based on the development of cannabis use disorder and/or cannabis psychosis. Analyses were performed to determine these conditions' risk factors. RESULTS: Multivariate analysis revealed that factors significantly associated with cannabis use disorders were “cannabis‐use initiation at a young age” (p = 0.004, OR: 0.951, 95% CI [0.920–0.984]), “family history of mental health problems” (p < 0.001, OR: 1.988, 95% CI [1.545–2.556]), “psychiatric disorders preceding cannabis use” (p = 0.039, OR: 1.672, 95% CI [1.026–2.722]), and “use of cannabis products other than dry flower” (p < 0.001, OR: 2.725, 95% CI [1.844–4.026]). Factors significantly associated with cannabis psychosis were “cannabis‐use initiation at a young age” (p = 0.011, OR: 0.888, 95% CI [0.811–0.973]) and “family history of mental health problems” (p = 0.002, OR: 2.531, 95% CI [1.400–4. 576]). CONCLUSION: Risk factors for problematic cannabis use were cannabis initiation at a young age, pre‐cannabis psychiatric disorders, family history of mental health problems, and the use of cannabis products other than dry flower. However, the causal relationship among these factors remains ambivalent.