Because currently there is no universally accepted definition of substance abuse, it is generally seen as an early form of a disease characterized by dependence criteria. This terminology has often led to confusion, both within the medical community and with the general public. However, it can be generalized to say that it is the overindulgence in and dependence on a drug or other chemical leading to effects that are detrimental to the individual’s physical and mental health, and/or the welfare of others.

Substance abuse may lead to addiction or substance dependence. Medically, physiological dependence requires the development of tolerance leading to withdrawal symptoms. Both abuse and dependence are distinct from addiction, which involves a compulsion to continue using the substance, despite the negative consequences, and may or may not involve chemical dependency. Dependence almost always implies abuse, but abuse frequently occurs without dependence, particularly when an individual first begins to abuse a substance. Dependence involves physiological processes, while substance abuse reflects a complex interaction between the individual, the abused substance, and society.

The fourth edition of the “Diagnostic and Statistical Manual of Mental Disorders” (DSM -IV) issued by the American Psychiatric Association, defines substance abuse as a “maladaptive pattern of substance use leading to clinically significant impairment or distress, as manifested by one (or more) of the following, occurring within a 12-month period:

Recurrent substance use resulting in a failure to fulfill major role obligations at work, school, or home (e.g., repeated absences or poor work performance related to substance use; substance-related absences, suspensions or expulsions from school; neglect of children or household);

Recurrent substance use in situations in which it is physically hazardous (e.g., driving an automobile or operating a machine when impaired by substance use);

Recurrent substance-related legal problems (e.g., arrests for substance-related disorderly conduct); and/or

Continued substance use, despite having persistent or recurrent social or interpersonal problems caused or exacerbated by the effects of the substance (e.g., arguments with spouse about consequences of intoxication, and/or physical fights).”

Note: Researchers have discovered that a large percentage of those who have substance abuse problems also suffer from other mental-health or personality disorders; this is known as a co-occurring disorder.