Screening and Brief Intervention As a Model to Identify and Reduce Marijuana Use Among Patients Seeking Health Care

Introduction: Cannabis is the most widely used illicit substance in the US. Nationally, rates of individuals seeking treatment for dependent marijuana have increased and the National Institute on Drug Abuse estimates that 9 percent of people who use marijuana will become dependent, a risk that increases to 25 to 50 percent among daily users. Screening and brief intervention (SBI) provides a means to identify and intervene with individuals engaging in non-dependent, risky substance use to meet public health goals of reducing the harms and societal costs associated with substance misuse. While the evidence-base for the efficacy of alcohol SBI has been well-established, additional studies on marijuana SBI are needed. We examined data from a federally-funded state SBI initiative in a variety of primary care settings to 1) identify predictors of patient risky marijuana use, 2) describe patterns of use among users, and 3) assess changes in use six months later.

Methods: 108,907 unduplicated patients in 12 diverse healthcare sites were screened (e.g., primary care clinics, hospitals, trauma units, a dental clinic). After a positive prescreen, health educators administered the ASSIST tool (developed by the World Health Organization) to assess the degree of risky use across multiple substances, and grant-required questions on demographics and past 30 day use. Health educators provided brief interventions to patients scoring positive for risky use. The mean age of patients screened was 44.2 years old (SD 17.7; range 18-85); 53% were female. A subsample of 552 patients who screened positive for marijuana at intake participated in an interview 6 months after screening.

 

Results: 8% of patients (n=8720) screened positive for harmful marijuana use. Results of logistic regression indicated that being male (OR=1.9), being younger (for every 10 years older, OR=0.63), and screening positive for alcohol (OR=2.7) or tobacco (OR=3.9) were each significantly associated with increased odds of a positive marijuana screen. Of patients who screened positive, 98% scored in the moderate risk level (non-dependent, yet potentially harmful pattern of use) and 26.7% used daily. Patients in the follow-up study significantly reduced their use in the prior 30 days from intake to follow-up by an average of 8.5 days (t (551) = 15.3, p < .001).    

Conclusions: Results of this study support SBI as an effective model to identify and intervene with patients using marijuana in order to reduce the risk of future dependency and related consequences. Predictors of use were consistent with those found in other studies. Over one-quarter of marijuana users were using daily without signs of dependence, providing the opportunity to intervene to reduce use before the onset of abuse or dependence.