Polysubstance dependence refers to a type of substance dependence disorder in which an individual uses at least three different classes of substances indiscriminately and does not have a favorite drug that qualifies for dependence on its own.
Polysubstance dependence is listed as a substance disorder in the Diagnostic and Statistical Manual of Mental Disorders published in 2000 (also known as the DSM-IV-TR ). The DSM-IV-TR is the latest revision of the manual that it is used by mental health professionals to diagnose mental disorders. When an individual meets criteria for dependence on a group of substances (at least three different types used in the same 12-month period) he or she is given the diagnosis of polysubstance dependence. For example, an individual may use cocaine, sedatives, and hallucinogens indiscriminately (i.e., no single drug predominated; there was no "drug of choice") for a year or more. The individual may not meet criteria for cocaine dependence, sedative dependence, or hallucinogen dependence, but may meet criteria for substance dependence when all three drugs are considered as a group.
Causes and symptoms
There is very little documented regarding the causes of polysubstance dependence.
The DSM-IV-TR specifies that three or more of the following symptoms must occur at any time during a 12-month period (and cause significant impairment or distress) in order to meet diagnostic criteria for substance dependence:
- Tolerance: The individual either has to use increasingly higher amounts of the drugs over time in order to achieve the same drug effect or finds that the same amount of the drug has much less of an effect over time than before. After using several different drugs regularly for a while, an individual may find that he or she needs to use at least 50% more of the amount they began using in order to get the same effect.
- Withdrawal: The individual either experiences the withdrawal symptoms when he or she stops using the drugs or the individual uses drugs in order to avoid or relieve withdrawal symptoms.
- Loss of control: The individual either repeatedly uses more drugs than planned or uses the drugs over longer periods of time than planned. For instance, an individual may begin using drugs (any combination of three or more types of drugs) on weekdays in addition to weekends.
- Inability to stop using: The individual has either unsuccessfully attempted to cut down or stop using the drugs or has a persistent desire to stop using. An individual may find that, despite efforts to stop using drugs on weekdays, he or she is unable to do so.
- Time: The individual spends a lot of time obtaining drugs, using drugs, being under the influence of drugs, and recovering from the effects of drugs.
- Interference with activities: The individual either gives up or reduces the amount of time involved in recreational activities, social activities, and/or occupational activities because of the use of drugs. An individual may use drugs instead of engaging in hobbies, spending time with friends, or going to work.
- Harm to self: The individual continues to use drugs despite having either a physical or psychological problem that is caused by or made worse by the use of drugs.
Young adults (i.e., between the ages of 18 and 24) have the highest rates of use for all substances. Generally, males tend to be diagnosed with more substance use disorders.
Individuals who abuse alcohol and other drugs usually meet criteria for substance abuse and/or dependence for each individual substance used. Multiple diagnoses are given in this situation (cocaine dependence, hallucinogen dependence, and sedative dependence, for example). Polysubstance dependence is reserved only for those situations when an individual uses multiple substances indiscriminately and meets criteria for dependence on these substances, taken as a whole.
There is very little documented regarding the treatment of polysubstance dependence. However, several treatments have been tried. Psychological evaluation and tests may be used to assess the affected individual. The person may be admitted into a hospital or treatment center as an inpatient, and/or he or she may receive cognitive-behavioral therapy .
The course of substance dependence varies from short-lived episodes to chronic episodes lasting years. The individual with substance dependence may alternate between periods of heavy use with severe problems, periods of no use at all, and periods of use with few problems.
The best single thing an individual can do to prevent polysubstance dependence is to avoid using drugs including alcohol altogether. On a larger scale, comprehensive prevention programs that utilize family, schools, communities, and the media (such as television) can be effective in reducing substance abuse.
American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders. 4th edition, text revised. Washington, DC: American Psychiatric Association, 2000.
Kaplan, Harold I., M.D., and Benjamin J. Sadock, M.D. Kaplan and Sadock's Synopsis of Psychiatry: Behavioral Sciences, Clinical Psychiatry. 8th edition. Baltimore: Williams and Wilkins.
Jennifer Hahn, Ph.D.