Recent large genome‐wide association studies (GWASs) have independently implicated a gene located on chromosome 3 encoding cell adhesion molecule 2 (CADM2) in various risky behaviors including alcohol (ab)use, 17 lifetime cannabis use, 1 number of sexual partners, 17 and age at first sexual intercourse. 18 Proteins encoded by CADM2 are involved in glutamate signaling, GABA transport, and neuron cell–cell adhesion, especially in the prefrontal and anterior cingulate cortices. 19 These brain regions are well known for their role in cognitive control and motivational salience, which are in turn involved in impulse regulation and self‐control. 20 , 21
