How personality and expectations shape cannabis use in Veterans

This study examined how impulsive personality traits influence cannabis and alcohol use among Veterans, testing a psychological theory called the Acquired Preparedness Model (APM). Researchers tracked 361 Veterans over one year using surveys conducted every six months, measuring personality traits related to impulsivity, their expectations about alcohol and cannabis effects, and their actual substance use patterns. The findings suggest that personality and expectations work differently depending on whether researchers compare individuals to each other versus tracking changes within the same person over time.

The research revealed an important distinction: positive expectations about cannabis and alcohol were linked to higher use frequency and quantity across Veterans, while negative expectations were associated with lower cannabis use. However, the theory that personality traits shape substance use through changing expectations over time did not hold true in this study. Between-person comparisons showed that more impulsive Veterans had more positive views about cannabis and alcohol, but these expectancies didn't explain why their substance use changed over the 12-month period. This suggests that the relationship between personality, beliefs, and behavior operates differently in the short term than theories predict, or that other factors unique to the Veteran population may be at play.

These findings have practical significance for Veterans and substance use counselors: understanding that positive expectations strongly predict use suggests that interventions targeting how people think about cannabis and alcohol effects—rather than focusing solely on personality traits—may be more effective. The research highlights that one-size-fits-all prevention models may not account for the unique experiences and sociocultural factors affecting Veterans, pointing to the need for tailored approaches to substance use management in military and Veteran populations.