Final answer:
According to social control theory, illicit drug use is primarily caused by the absence of a stake in conformity to the norms of conventional society, as individuals disconnected from society are more likely to engage in such behaviors.
Step-by-step explanation:
According to social control theory, one of the major causes of illicit drug use is a. the absence of a stake in conformity to the norms of conventional society. This concept is rooted in Travis Hirschi's Control Theory, which suggests that social control is directly affected by the strength of social bonds and that deviance, including illicit drug use, results from a feeling of disconnection from society. Individuals who have weak attachments to the community, lack commitment to social norms, are minimally involved in socially legitimate activities, and do not believe in common values are more likely to engage in illicit drug use.