Body image disturbance in body dysmorphic disorder and eating disorders. Obsessions or delusions?

At this time, the question posed by this article's title--body image disturbance in body dysmorphic disorder and eating disorders: obsessions or delusions?--is probably best answered "both." Both disorders appear to be characterized by obsessional and delusional thinking. In addition, it is likely that their nondelusional and delusional variants constitute a single disorder encompassing a spectrum of insight, with the entire spectrum characterized by obsessional thinking. This view represents a considerable departure from DSM-III-R, in which the psychotic disorders were encapsulated in a separate section of the manual and considered different disorders from their nonpsychotic variants. The one exception was the mood disorders, which were acknowledged to have psychotic variants that were classified in the manual's "nonpsychotic" section. In DSM-IV, on the basis of emerging empirical evidence about the dimensional nature of the psychotic/nonpsychotic boundary, the dichotomy between delusional and nondelusional disorders is less clear. The double coding allowed for BDD acknowledges that BDD and its delusional disorder variant may constitute a single disorder; that allowed for OCD acknowledges that OCD may be delusional. With regard to eating disorders, however, DSM-IV is surprisingly silent, perhaps because delusional preoccupations are less common than in BDD. These issues also may apply to other disorders. Like BDD, hypochondriasis is classified as a somatoform disorder, with its delusional variant a type of delusional disorder, somatic type. Do the delusional and nondelusional variants of hypochondriasis constitute the same disorder? Do other types of somatic delusional disorder, such as parasitosis and olfactory reference syndrome (the belief that one emits a foul body odor) have nondelusional variants? It is likely that a number of disorders span a spectrum from delusional to nondelusional thinking, with unlimited shades of gray in between. Future research may indicate that obsessional disorders such as BDD, anorexia, OCD, and hypochondriasis, as well as other disorders such as major depression, should have qualifiers or subtypes--for example, "with good insight," "with poor insight," and "with delusional (or psychotic) thinking"--with an implied continuum of insight embraced by a single disorder. Such an approach, which scatters psychosis throughout the nomenclature, ultimately may be shown to be a more valid and clinically useful classification approach. Answers to these questions will not only improve our classification system but also may have important treatment implications. For example, the preliminary finding that delusional BDD responds preferentially to SRIs but not to neuroleptic agents contradicts conventional wisdom about the treatment of psychosis.(ABSTRACT TRUNCATED AT 400 WORDS)