An addiction can be classified as a mental illness as it is the progressive psychological deterioration resulting from dependence on a substance. Like other mental illnesses, substance abuse affects people from all ethnic, cultural and socioeconomic backgrounds. Genetics, environment, childhood experiences, peers and trauma play a significant role in the development of an addiction. Addiction is defined as a physical and psychological dependence on a mind-altering substance or as the compulsive dependence on a psychoactive substance.
The World Health Organization defines addiction as a dependence syndrome. The term dependence is used by the WHO in replacement of addiction, although they are both considered the same condition. This syndrome is a cluster of physiological, behavioral and cognitive phenomena that develops after repeated substance use.
The clinical definition of dependence syndrome, or addiction, includes the following elements:
- A strong desire or sense of compulsion to take the addictive substance
- Difficulties in controlling addictive behavior especially difficulty in stopping the consumption of substance and lack of control over quantity that is consumed.
- Physiological and psychological withdrawal symptoms when substance use has ceased or have been reduced e.g. tremors, irritability, hallucinations, anxiety etc.
- Evidence of tolerance, such that increased doses of the psychoactive substance are required in order to achieve effects originally produced by lower doses. In simple words, the body and mind develops tolerance to increasing amount of addictive substance.
- Neglect towards other non addictive forms of pleasure.
- Persistent substance use despite of overtly harmful consequences e.g. harm to the liver through excessive drinking, depressive mood states consequent to periods of heavy substance use, or drug-related impairment of cognitive functioning.