Personality Pathology Severity and Hazardous Cannabis Use: Does Instability in Daily Life Mediate This Association?

Comorbidities between personality pathology and cannabis use disorders among young adults are a growing public health concern. Young adulthood is the period in which personality pathology and associated dysfunction peak, and evidence suggests personality pathology contributes to substance abuse behaviors. However, the specific aspects of personality pathology that explain these associations remain unclear. Personality disorders tend to share in common three domains of dysregulation that are marked by instability in self-esteem (identity), affect, and interpersonal experiences. This study investigated whether these common domains of personality dysfunction mediated associations between personality pathology severity and patterns of cannabis use. The current study used data from a community-based sample of 186 young adults (ages 18-30; mean age = 21.09 years [SD = 2.35], 60% female, 72% White; 74% college students) who reported using cannabis at least twice per month over the past six months. Momentary data on psychological states and cannabis use were collected via 8 daily surveys over 21 days. Mediation analyses showed indirect effects of personality pathology severity on hazardous cannabis use through within-day instability in self-esteem and in interpersonal experiences, but not through instability in affect. Further, participants with greater personality pathology demonstrated greater instability, but instability was associated with less hazardous cannabis use. These unexpected results emphasize the need to consider interpersonal and identity-related constructs in research examining contributors to comorbid cannabis and personality pathology. Instability in self-esteem and in interpersonal experiences should be explored further in future studies, as they may be targets for clinical intervention in young adults with personality pathology who hazardously use cannabis.