A few theories have been proposed to explain the development and maintenance of body dysmorphic disorder (BDD). Although the biological research is limited, there are some preliminary neurochemical and neuroanatomical theories. This chapter will review established psychological learning theories, with an emphasis on the cognitive behavior model.
Many of the biological models of BDD are derived from treatment responses to the class of medications calledselective serotonin reuptake inhibitors (SSRIs), neuroimaging studies, and neuropsychological test findings. Etiology should not be inferred from any of these studies, and functional differences do not necessarily implicate neurological dysfunction as a causal factor. Most of the neurochemical theories of BDD are based on OCD research, because of BDD’s similarity to OCD. In addition, similar to OCD, SSRIs are used to treat BDD, and therefore it is assumed that serotonin is involved in its etiology. However, there are relatively few randomized controlled studies exploring the efficacy of SSRIs. In one study, a serotonin reuptake inhibitor (SRI; clomipramine) was compared with a norepinephrine reuptake inhibitor (NRI; desipramine) and was found to be superior (Hollander et al., 1999). Many anxiety disorders also respond to SRIs better than NRIs, and therefore this difference does not necessarily establish causation. However, there are case examples in the literature that implicate serotonin as a possible etiological factor. These cases suggest that a serotonin receptor agonist or serotonin receptor antagonist can reduce or increase symptoms of BDD. The former involved the use of psilocybin (Hanes, 1996), and the latter chlorophenylpiperazine (m-CPP;Hollander& Wong, 1995) and cyproheptadine (Craven& Rodin, 1987). In another study, 5-hydroxytryptophan, a precursor of serotonin, led to an exacerbation of symptoms (Barr et al., 1992). However, again neither depletion of tryptophan nor use of serotonergic receptor antagonists, both of which increase BDD symptoms, are sufficient to indicate that serotonin is
