People with substance use disorders usually have symptoms of anxiety and depression. According to the National Institute on Drug Abuse (2007), people with mood or anxiety disorders are twice as likely to be diagnosed with a substance use disorder. The reverse is also true: Compared to the general population, people with substance use disorders are two times as likely to be diagnosed with a mood or anxiety disorder (National Institute on Drug Abuse, 2007). In addition, the 12-month prevalence of people having both a substance use disorder and a mood or anxiety disorder is approximately 20% and 18%, respectively (Grant et al., 2004). Some people may use drugs in an attempt to alleviate these psychological symptoms by self-medicating. Others may experience the depression and anxiety because of their substance use. In many cases, it is likely that both of these scenarios may be occurring (Kaplan & Sadock, 1991). The presence of these co-occurring disorders may make treatment more complicated and often predicts a poorer outcome. People with both a substance use disorder and depression are more likely to commit suicide than either disorder alone (APA, 2000).
Compulsions are repetitive behaviors that serve to relieve anxiety. These behaviors are usually associated with a disorder called obsessive-compulsive disorder LINK. People generally do not enjoy performing their compulsions. Instead, they feel driven to perform them. People with moderate to severe forms of substance use disorder (addiction) often exhibit compulsive drug use. This means they feel driven to substance use as a means of coping with the anxiety associated with cravings. As use continues, cravings typically become stronger. This creates a vicious cycle: More use leads to more craving, which leads to more use, and so forth. Of course, the compulsion would not have developed in the first place if the substance or activity were not pleasurable. Therefore, the repeated pleasurable use of a substance or activity leads to craving. Cravings then lead to compulsive use in order to reduce the tension of craving.