[The concept of insight in patients with obsessive-compulsive disorder].

OBJECTIVE To update clinicians regarding the existence of a putative subtype of obsessive-compulsive disorder based on poor insight. METHOD Opinionative review based on studies indexed in the PubMed and PsychINFO databases, identified by means of the keywords 'obsessive-compulsive disorder' AND 'insight' OR 'ego-syntonic', and published between 1966 and October 2009. The results were analyzed according to the approach adopted, i.e. a categorical or dimensional view of insight in obsessive-compulsive disorder. RESULTS The review of recent studies led us to identify some issues that cast doubts over the existence of a clear-cut poor insight subtype of obsessive-compulsive disorder. These issues include 1) an extremely variable prevalence of poor insight obsessive-compulsive disorder in categorical studies, 2) a significant degree of homogeneity in the phenotypical findings (i.e. greater severity) associated with lower levels of insight in obsessive-compulsive disorder in both categorical and dimensional studies and, 3) a lack of studies investigating zones of rarity between poor and good insight obsessive-compulsive disorder. CONCLUSION Although a categorical approach to the insight issue in obsessive-compulsive disorder is still important in clinical settings, where decision-making is often a critical issue, a dimensional approach seems to reflect levels of impairment in these patients more reliably.