The most common mood disorder is a substance-induced mood disorder. For most people, this disorder manifests during periods of intoxication or withdrawal. Studies have shown that almost 40% of alcoholics and over 50% of persons with other drug addictions manifest symptoms of mood disorder. The most common mood disorder is major depression, which is most prevalent in heroin and methadone addicts.
Most patients with alcohol and other drug (AOD) disorders manifest symptoms of depression during treatment for addiction. Further, most patients manifest symptoms of depression in the first few months of sobriety. However, the symptoms fade with time as the withdrawal symptoms improve. The research also indicates that women with AOD have higher rates of mood disorders than men. Meanwhile, elderly patients with AOD problems are at a high risk of mood disorders because the frequency of mood episodes increases with age.