According to cognitive-behaviorists, may play a key role in substance use disorders. This is because the temporary reduction of tension or raising of spirits produced by a drug has a rewarding effect, thus increasing the likelihood that the user will seek this reaction again.

Operant conditioning

Explanation:

A learning process in which an organisms behavior gets associated with some kind of punishments or reward on behalf of that behavior is called operant conditioning.

In the stated situation, the intake of drug reduces the tension and produces a relaxing effect on mind. In order to get this effect again, the user seeks to take the drug again. Thus we can state that his behavior of taking drugs has associated itself with the rewarding effect of reduced tension . Hence, it is operant conditioning that has played the role in the substance use disorder.

sorry, but you do not have posted the diagram.