The Psychology of Addiction
Almost all substance use affects the “reward mechanism” in the brain. The main chemical messenger involved in the brain’s reward mechanism is dopamine. Each time the person uses a substance they will tend to feel ‘good’, which makes them want to use the substance again. Over time, changes in the brain occur (e.g. less dopamine is produced), which lessens the pleasurable effects of the substance and therefore larger amounts are needed to get the same affect.
The early stages of addiction are actually associated with both positive and negative reinforcements. Reinforcement refers to a process in which the substance use behaviour is strengthened due to previous consequences experienced by the user as a result of the substance use behaviour.
Positive reinforcement refers to a situation where there is a rewarding experience obtained from the using behaviour (for example, feeling calm and relaxed after smoking cannabis or feeling sociable after drinking alcohol). The rewarding experience increases the probability of the using behaviour occurring again, in order for the user to have the rewarding experience again.
For example: if a person feels relaxed after drinking alcohol, they are more likely to use alcohol to obtain that same relaxed feeling again.
Negative reinforcement refers to a situation where there is a negative experience avoided as a result of the using behaviour (for example, a person may be able to avoid the feelings of anxiety by smoking cannabis or avoid social anxiety by drinking alcohol). The successful avoidance of the negative experience through the using behaviour increases the likelihood of the behaviour occurring again in order to avoid the same negative experience again (Koob & Simon, 2009; Gilpin & Koob, 2008).
It is common for individuals to get caught up in the addictive use and abuse of substances in order to eliminate negative emotions such as stress, depression, anxiety and irritability. After repeated use, an individual will come to realise that they don’t experience these emotions when they use the desired substance. This operates as a motivator for continued use, not only to avoid such negative reinforcers but also to manage withdrawal symptoms that they may have experienced following cessation of the substance at various times (McMullin, 2000; Gilpin & Koob, 2008). In this sense addicted individuals do not only use substances to avoid negative emotions and chemically induce more positive side effects, the motivation for continued use is also fuelled by the physiological and psychological need to manage withdrawal symptoms that develop with their dependency (Gilpin & Koob, 2008; McMullin, 2000).