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Causes of Addictions

In most Western industrialized nations, exposure to addictive and illicit substances is a matter of course for most people by the time they enter late adolescence or early 20's. The question thus becomes why some people but not others come to abuse these substance or become dependent upon them.

Biological Causes of Addictions

Over 50% of the risk of developing Abuse or Dependence to alcohol and other substances can be attributed to genetic factors [ref, ref]. For the most part, these genetic factors account for the risk of becoming addicted to substances in general and not to any one substance in particular [ref]. These genes likely contribute to the development of certain personality traits that make individuals prone to addictive behaviors [ref] (see Psychological Roots below).

Each substance has its own unique mechanism for inducing altered states of mood and consciousness in users (see this site's documentation of each individual substance for further information). However, a common underlying biological pathway for why many of these substances lead to addictions is the dopaminergic reward pathway. This brain circuit is responsible for the anticipation and the experience of reward. It is what allows people to remain focused on a goal, to anticipate the satisfaction of achieving this goal, and to feel pleasure and contentment when the goal is achieved.

Many substances are able to stimulate the dopaminergic reward pathway, which then produces a feeling of euphoria, or a 'high.' This becomes very reinforcing, meaning that cravings soon develop for repeated use of the substance in order to re-experience the 'high.' These cravings are mediated by the dopaminergic reward pathway. Once this brain circuit has identified the substance in question as something that can bring a sense of reward, it then focuses the mind on obtaining this substance again and again.

Psychological Roots of Addictions

There are certain personality traits, such as Impulsivity and Sensation-Seeking, that increase the risk of individuals developing addictions [ref, ref].

Impulsivity is defined the tendency to act on impulse without much thought or concern for the consequences of these actions.

Sensation Seeking is the tendency for one's actions to be guided by the pursuit of powerful experiences and sensations.

These traits make it more likely that someone will experiment with substances in reckless and dangerous ways. These traits may also make individuals more prone to succumbing to their cravings and repeatedly using substances in a way that can lead to abuse or dependence. Conduct Disorder, Antisocial Personality Disorder, and ADHD, which are all conditions characterized by these personality traits, are known to increase the risk of people developing substance use disorders [ref, ref].

There is also the theory that some individuals come to use substances excessively as form of self-medication to ease the symptoms of other underlying problems. For example, people suffering from Depressive Disorders may turn to alcohol or drugs to ease their psychological suffering or elevate their moods [ref]. Individuals with Social Anxiety Disorder tend to use alcohol or cocaine to lower their inhibitions and increase their self-confidence so that they may better manage social situations [ref, ref]. Similar examples could be found for most other Mood and Anxiety Disorders.

Having experienced traumatic events during childhood may also increase a person's chances of developing a substance use disorder later in life, especially when it comes to alcoholism [ref].

Social Factors Contributing to Addictions

Environments wherein the use of certain substances is common, permitted or encouraged will tend to have higher rates of individuals abusing those substances. For instance, peer pressure among adolescents and young adults is known to be a powerful force in leading individuals to use substances. Certain subcultures of society tend to encourage the use of particular substances, like Ecstasy use in rave culture. Nicotine and alcohol are used for more commonly in the US than other substances [ref], in large part because these substances are legalized and accepted, in contrast to certain Muslim countries where alcohol is contraband and thus far less commonly used. Individuals from families where substance use is common will also tend to be at higher risk for abusing substances themselves [ref, ref]; which is likely not explained simply by genetic factors.


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