Cannabis risks differed by psychosis-like experiences in BPD

BackgroundIndividuals with borderline personality disorder (BPD) frequently use cannabis, often for self-medication. However, cannabis use has also been linked to BPD symptom severity, suggesting heterogeneity in its effects. Individuals with BPD frequently experience psychotic-like symptoms and may demonstrate elevated psychosis vulnerability, which is associated with greater symptom severity and poorer clinical outcomes. Cannabis use may exacerbate psychotic symptoms. The relationship between psychosis vulnerability and BPD symptoms may therefore be influenced by cannabis use. This study examined whether cannabis use interacts with psychotic-like experiences (PLEs) in relation to BPD symptom severity in a clinical sample.MethodSeventy-nine outpatients with BPD completed questionnaires assessing BPD symptom severity, cannabis use, and PLEs. Moderation analyses tested whether cannabis use influenced the association between PLEs and BPD symptoms.ResultsCannabis use significantly moderated the relationship between PLEs and BPD symptom severity (ΔR2 = 0.069, P = 0.006), such that the association between PLEs and BPD symptoms strengthened as cannabis use increased. A crossover interaction was observed: the lowest BPD symptom scores occurred in individuals with low PLEs and high cannabis use, whereas the highest BPD symptom scores occurred in those with high PLEs and high cannabis use. In addition, PLEs moderated the relationship between cannabis use and BPD symptoms, such that cannabis use was negatively associated with BPD symptoms among individuals with low PLEs (β = -0.358, P = 0.018).ConclusionsPLEs appear to be an important factor in understanding heterogeneous associations between cannabis use and BPD symptom severity. Individuals with BPD who endorse elevated PLEs may benefit from targeted psychoeducation regarding cannabis-related risks and consideration of treatment for cannabis use disorder when clinically indicated. Conversely, the observed negative association between cannabis use and BPD symptoms in individuals with lower PLEs warrants further study of clinically meaningful heterogeneity and individualized treatment approaches. Psychotic-Like Experiences May Help Explain Different Cannabis-Related Patterns in Borderline Personality DisorderPlain Language SummaryBorderline Personality Disorder (BPD) is a mental health condition involving difficulties with emotions, relationships, impulsivity, and risk of self-harm. Many people with BPD use cannabis, sometimes to cope with distress. However, cannabis-related outcomes in BPD may differ from person to person.This study examined whether psychotic-like experiences (PLEs) help explain differences in the relationship between cannabis use and BPD symptoms. PLEs include experiences such as unusual perceptions, suspiciousness, or unusual thoughts. We analyzed questionnaire data from 79 adults receiving treatment in a specialized outpatient BPD program.We found that PLEs were strongly related to BPD symptom severity. Cannabis-related problems also influenced this relationship. Among people with higher PLEs, higher cannabis-related problem scores were associated with greater BPD symptom severity. Among people with lower PLEs, higher cannabis-related problem scores were associated with lower BPD symptom severity.These findings suggest that the relationship between cannabis and BPD is not the same for everyone. Psychotic-like experiences may identify a subgroup of individuals with BPD who experience different cannabis-related risks. Because this study was cross-sectional, it cannot show whether cannabis use caused these differences or whether cannabis is helpful or harmful for any subgroup. Future research following people over time is needed to better understand how cannabis use, psychotic-like experiences, and BPD symptoms influence one another.