Orbitofrontal cortex volume prospectively predicts cannabis and other substance use onset in adolescents.
Identifying neural characteristics that predict cannabis initiation is important for prevention efforts. The orbitofrontal cortex is critical for reward response and may be vulnerable to substance-induced alterations. We measured orbitofrontal cortex thickness, surface area, and volume prior to the onset of use to predict cannabis involvement during an average nine-year follow-up. Adolescents ( Larger left lateral orbitofrontal cortex volume predicted classification as cannabis user by follow-up ( Larger left lateral orbitofrontal cortex measured from ages 12-15 years and prior to initiation of substance use was related to greater reward responsiveness at baseline and predicted classification as a cannabis user and cannabisalcohol co-user by final follow-up. Larger lateral orbitofrontal cortex volume may represent aberrant orbitofrontal cortex maturation and increasing vulnerability for later substance use.