This is a double-blind, placebo-controlled, randomized clinical trial. 100 individuals with moderate to severe cannabis use disorder (CUD) will be randomized in a 1:1 ratio to receive either (1) weekly subcutaneous injections of tirzepatide or (2) weekly subcutaneous injections of matching placebo for 24 weeks. Tirzepatide will be initiated at 2.5 mg for 4 weeks (4 injections) and increased in 2.5 mg increments every 4 weeks as tolerated, up to a maximum dose of 15 mg.
The Primary Objective is to determine the maximum tolerated dose (MTD) of tirzepatide in individuals with CUD and to evaluate its efficacy in reducing cannabis use.
The primary Hypothesis is that tirzepatide will be well tolerated within the FDA-recommended dose range and compared with placebo, it will result in a significantly greater proportion of cannabis abstinent days as measured by the timeline follow-back (TLFB).
Secondary Objectives are to evaluate the effects of tirzepatide, relative to placebo, on (1) CUD severity based on DSM-5 criteria; (2) percentage of cannabis-negative weekly urine drug screens collected during the treatment period; (3) cannabis craving; (4) cannabis withdrawal severity; (5) retention in treatment; and (6) quality of life.