According to the National Comorbidity Survey, the dually diagnosed patient begins to experience their mental illness or psychiatric problems an average of 10 years prior to the onset of an addictive disorder or substance abuse.
There are a few theories on why those who suffer from mental disorders are more susceptible to illicit drug and alcohol abuse. From a socioeconomic viewpoint, many of those who are severely afflicted by their mental illness may be living in areas where drug use is more prevalent, have fewer resources, and a smaller support network if any. In this type of situation, it is simple to see the ease with which the more vulnerable would become involved with drug and alcohol use.
Self-Medication is another strong argument that has been made in connection with substance abuse. In an attempt to get relief from the symptoms of the disorder, a drug would be used. For example, if a man suffered from severe depression, he might find temporary relief in the euphoric effects of alcohol. Conversely, if a woman with Bipolar were experiencing a manic high, she might seek out a sedating drug such as marijuana or even heroin to ease the severity of her symptoms.
Large studies that have been conducted include major mental illnesses and disorders
For more information about specific mental illnesses, go to NAMI's "by Illness" page
For statistical and resesearch purposes, each organization will have its own standards for determining which disorders and what level of function of symptoms meet their criteria. The Global Assessment of Functioning (GAF) Scale is a widely used tool to evaluate an individual's level of functioning for both studies and as a tool to measure progress.
What does all this mean?
A co-occuring disorder makes the challenge of recovery from both addiction and mental health issues much more difficult, since the two illnesses feed off each other. Medication management, therapy, peer groups, and cognitive therapy are all essential elements in successful recovery from a mental illness - but when substance abuse enters the picture, many of these fall short as priorities. When abusing substances, the addict or alcoholic may begin to miss doses of prescribed medications, avoid social interaction, and find the ability to focus on cognitive therapy diminish. Additionally, the side effects and long term effects of many drugs can mimic and exacerbate mental illnesses, making diagnosis and treatment even more difficult for mental health providers and rendering some medications ineffective or harmful when used in combination with street drugs.