Dual Diagnosis
Dual diagnosis, comorbidity, and co-occurring disorders are term that describe concurrent mental illness and drug abuse or dependence. These disorders occur at the same time, or one follows the other, and eventually it is difficult to tell which came first. Even though the diseases of mental illness and drug abuse are comorbid, causality is not implied and either condition may precede the other. The symptoms of one condition often mask or conceal the symptoms of the other, and either condition assumes priority at any given time. Even though dual is common terminology, it is important to recognize that many individuals suffer from two or more disorders concurrently. For example, a person exhibits signs of severe psychosis, depression, and cocaine dependence. Approximately 30% of individuals diagnosed as mentally ill abuse drugs or alcohol; 37% of alcohol abusers and 53% of drug abusers also have at least one mental illness. The most prevalent psychiatric disorders among those with a history of substance abuse are antisocial personality disorders, bipolar disorders, and schizophrenia. Substances individuals most often abuse are alcohol, followed by marijuana and cocaine. Many patients with severe and persistent chronic mental illness are also addicted to nicotine.