Read the following information.

Research has found that an important factor affecting teenage drug use is whether or not drug use is common within a teenager's friendship group. Another important factor is the way that the teenagers' role models talk about drug use.

Briefly outline one psychological explanation of addiction.
Refer to the information in your answer.

Social Learning Theory (SLT), proposed by Albert Bandura, is a key explanation for the initiation of addictive behaviours. SLT suggests we learn by observing others (models). If a teenager observes their peers or role models engaging in drug use (observation) and sees them experiencing positive consequences like social acceptance or pleasure (vicarious reinforcement), they are more likely to copy that behaviour (imitation). The information in the question directly points to these social influences, making SLT a perfect fit.