American Psychiatric Association (1994) (the DSM-IV) lucidly groups all addiction to and abuse of substances into a single chapter: Substance Related Disorders. There is no single theory which accounts for why some people abuse substances and others don't (Straussner, 1993), but the presenting picture is essentially the same regardless of the substance.
In all probability, addiction (like so much mental illness) has a multifactorial etiology. Thus it must be viewed in a biopsychosocial framework. Straussner (1993) concludes that,
It may be best to view substance abuse as a multivariate syndrome in which multiple patterns of dysfunctional substance abuse occur in various types of people with multiple prognoses requiring a variety of interventions (p. 11).
Here are some of the predisposing factors:
1. the possibility of a biochemical or genetic factor in intergenerational transmission;
2. familial factors such as early separation from one or both parents early in life; inadequate parenting during childhood; physical or sexual abuse, or growing up in a family with multigenerational abuse of substances;
3. all of the psychological theories posit psychological factors in the development of addiction. For all the "insight" provided by these theories, none of them leads to any more effective intervention than the others. In fact, those willing to be straightforward on this subject admit that psychotherapy of any ilk is largely ineffective in treating active addiction. If the proof of the pudding is in the eating, it is then apparent that the following classic psychological bromides are wrong and/or irrelevant:
The addict uses the substance:
- as a substitute for unacceptable sexual or aggressive drives, as a substitute for the primal addiction to masturbation, or as a defense against homosexuality;
- as the result of a fixation in and a regression to the oral stage of development;
- in response to an underlying neurosis based on the conflict between dependence and anger, or
- as slow suicide (Straussner, 1993).
Other more modern theoretical perspectives focus equally ineffectively on poor ego development, pathological narcissism, or a deficiency in the sense of self (Straussner, 1993).
More useful theories for treating an individual in later-stage recovery suggested that,
- the addict attempts to medicate emotional problems such as depression, anxiety and anger;
- express dependency needs;
- compensate for feelings of inferiority and powerlessness, or
- relate to such things as low frustration tolerance, high level of impulsivity, or the inability to endure even low-level anxiety (Straussner, 1993).
Learning and behavioral theorists see addiction as a conditioned response; it produces a pleasurable high (perhaps very pleasurable in some, making them more willing to accept the negative consequences of indulgence) or relieves pain (as suggested above). Because children raised by addicted non-biological parents are at a higher risk of alcoholism than children raised by non-addicted non-biological parents, expectancy, modeling, imitation and identification may also predispose to substance abuse (Straussner, 1993).
4. environmental and cultural factors in general can play a role in the etiology of addiction, such as:
- availability of the substance (e.g., many soldiers became addicted to heroin in Vietnam because of  the high stress of war, and  the availability of the substance, but upon return to civilian life a large proportion of them ceased to have problems with drugs and alcohol);
- lack of rewarding alternatives in life (e.g., lack of decent living conditions or opportunity to earn an income, as might be experienced by persons living in a minority ghetto),
- influence of mass media, or
- social or peer acceptance of use of the substance.
Finally, regardless of the theory of addiction or the predisposition of the person to addiction, almost anyone who takes a mood-altering substance in large quantity for a long enough time will experience physical and/or psychological dependence (Straussner, 1993).