A unified cause of addiction is not known and, in fact, researchers can't even agree on a standard definition of addiction or whether addiction is a disease. The latest version of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR) lists substance use disorders, not addiction.1 Substance use disorders pertain specifically to psychoactive substances such as heroin and tobacco. Impulse control disordersare also listed and are similar to the concept of behavioral addictions.
An "addiction gene" has not been located, but addiction often runs in families suggesting a link between addiction and genetics. Studies on twins also lends support to the impact of genetics on addiction.2
What is an Addictive Personality?
As researchers continue to look at the science of addiction, more addiction theories are found. The idea of an "addictive personality" is one such theory. Addictive personalities are those that are more likely to become addicted to a substance or behavior. It is thought people with addictive personalities have personality traits like:3
- Impulsive behavior
- Lack of interest in goals and achievement
- Social alienation
- High stress levels
Addiction and the Brain
The impact of addiction on the brain is better understood for psychoactive substances such as alcohol and cocaine. While each substance impacts the brain differently, the addiction cycle tends to be similar:
- Psychoactive substances initially quickly produce euphoria from the flood of certain chemicals in the brain.
- After the euphoria, unpleasant withdrawal symptoms occur.
- The addict, wishing to again experience the euphoria, or to escape unpleasant withdrawal (craving), is highly motivated to use the substance again.
This cycle is thought to be, in part, because of the reward circuit in the brain. When the brain finds something rewarding (pleasurable), it creates a pleasurable memory and increases the motivation to experience pleasure again. This can alter the brain's neurotransmitters (chemicals). Parts of the brain linked to the reward circuit and addiction include:4
- Ventral tegmental area (VTA)
- Nucleus accumbens
- Locus ceruleus
- Dopaminergic mesolimbic system
- Frontal cortex
- GABAergic inhibitory fiber system (GABA)
Is Addiction a Disease?
Just as an addiction gene has not been found, neither has a satisfactory decision been reached about whether addiction is a disease. Researchers and doctors can't determine what causes addiction or how it should be treated. While the most common model of addiction treatment involves abstinence from the substance, this clearly does not work for behavioral addictions like sex addiction and food addiction (if one considers those to be addictions).
Some experts claim addiction is not a disease due to the faulty assumptions on which the disease model is built, noting many supposed addicts curb usage or become abstinent on their own.5 On the other hand, the National Institute on Drug Abuse clearly states addiction is a chronic disease.6