The mechanisms of addiction and impairments related to drug use

Abstract: This thesis contains an overview of the mechanisms of addiction as well as a description of the impairments related to drug abuse. The general view of addiction is that it depends on three characteristics that have separate neural mechanisms, called “wanting”, liking and learning. “Wanting” is described as a desire evoked by reward cues, liking refers to the pleasure of getting a reward and learning is described in terms of classical conditioning. “Wanting” and liking are usually in agreement but in addiction they are dissociable, that is, wanting a drug but getting no pleasure from it. Reward cues, acquired through learning, awakes the motivation to obtain the drug again. This can be problematic when trying to cease drug taking. The dopamine system in the brain is much discussed in relation to addiction and its neural correlates. The prefrontal cortex (PFC) is suggested to be altered in addiction, and this may underlie some of the impairments discussed. Addiction is also strongly related to cognitive impairments such as working memory problems, impulsivity, attentional problems and decision-making impairments. Affective impairments, such as empathy problems, may also to have some connection to addiction, although this is less clear.