The Diagnosis and Treatment of Substance Abuse/ Dependence and Co-Occurring Social Anxiety Disorder

One possible neurobiological link between social anxiety disorder and substance dependence may be the neurotransmitter dopamine(Drug information on dopamine). Individuals with social anxiety disorder have been shown to have a decreased binding of dopamine in the basal ganglia (Tiihonen et al., 1997) and social anxiety disorder has been shown to have a high incidence in individuals with parkinsonism (Stein et al., 1990), a disease known to be associated with decreased dopamine binding. Some have theorized that dopamine, especially striatal dopamine, is a key component in the manifestation of social anxiety disorder and that it acts as a gatekeeper for the involvement of other neurochemicals, such as serotonin or γ-aminobutyric acid (GABA) (Li et al., 2001).

Interestingly, all drugs of abuse ultimately increase dopamine in the basal ganglia (Kalivas, 2001). Although it does not explain the ultimate development of substance dependence, if the hypoactive dopaminergic tone associated with social anxiety can be temporarily ameliorated with drugs of abuse, this may explain why a person with social anxiety disorder may find using drugs to be effective self-medication.

Another possible neurochemical link between social anxiety disorder and substance dependence may involve the neurotransmitter GABA. Although an animal model of social anxiety disorder has been somewhat elusive, there is considerable preclinical evidence to support a role for GABA in anxiety disorders in general. Several studies have shown that, in a mouse model, an inhibited ability to synthesize GABA results in increased anxiety (Kash et al., 1999; Stork et al., 2003, 2002). In addition to preclinical data that support the role of GABA in anxiety in general, pharmaceutical agents that enhance GABA-for example, benzodiazepines and non-benzodiazepine anticonvulsants-have been shown to be effective in the treatment of social anxiety disorder (Davidson et al., 1991; Pande et al., 2004, 1999; Van Ameringen et al., 2004). Although not quite as central as dopamine, GABA also plays an important role in addiction (Malcolm, 2003).

If a patient presents with both disorders to either an addiction or an anxiety treatment setting, what is the optimal treatment approach? Unfortunately, there has been little work done in this area. As most treatment facilities rely heavily on traditional group therapy and 12-step treatment approaches (such as Narcotics Anonymous or Alcohol(Drug information on alcohol)ics Anonymous) for the treatment of SUDs, individuals with social anxiety may have considerable difficulty engaging and participating in such group-oriented activities. As such, a tailored approach to treatment including more individualized treatment and strategy development for participation in groups is needed.

Some of the medications used for social anxiety, for example the benzodiazepines, may not be safe to use if the patient has a co-occurring addiction (Book and Randall, 2002). The selective serotonin reuptake inhibitors are the first line treatment of social anxiety disorder (Ballenger et al., 1998) and, although there is some evidence that they can worsen addiction in some populations (Kranzler et al., 1996; Pettinati et al., 2000), in the right patient with social anxiety disorder and co-occurring addiction, they may be the best choice. The efficacy of paroxetine(Drug information on paroxetine) (Paxil) for individuals with social anxiety disorder and a co-occurring alcohol use disorder has been evaluated (Randall et al., 2001). They found that the paroxetine-treated participants had significantly more improvement of social anxiety than did the placebo-treated participants over the eight-week study. However, although the alcohol use variables also were more improved in the paroxetine group than they were in the placebo group, the difference was not significant. This pilot study is currently being followed up on a larger scale. Although the work of Zimmermann et al. (2004) and of Myrick and Brady (1997) would indicate that treatment solutions are needed for individuals with social anxiety disorder and drug addiction, no such studies have been done. Clearly, research trials involving therapeutic approaches to treat comorbid social anxiety and substance use disorders are needed.

Supported by National Institute of Alcohol Abuse and Alcoholism grants 2 P50 AA10761-03, K23 AA014430 (SWB) and K23 AA00314-01 (HM), and a U.S. Department of Veterans Affairs Merit Grant (HM).