Body dysmorphic disorder (BDD) has both psychotic and nonpsychotic variants, which are classified as separate disorders in DSM-IV (delusional disorder and a somatoform disorder). Despite their separate classification, available evidence indicates that BDD's delusional and nondelusional forms have many similarities (although the delusional variant appears more severe), suggesting that they may actually be the same disorder, characterized by a spectrum of insight. And contrary to what might be expected, BDD's delusional form, although classified as a psychotic disorder, appears to respond to serotonin-reuptake inhibitors alone. These and other data suggest that a dimensional view of psychosis (in particular, delusions) in these disorders may be more accurate than DSM's current categorical view. A dimensional model might also facilitate more consistent and accurate classification of other disorders that are likely characterized by a spectrum of insight, such as obsessive compulsive disorder, hypochondriasis, and anorexia nervosa. Further research is needed to better understand these classification issues, which likely have treatment implications.