Can obsessions drive you mad? Longitudinal evidence that obsessive-compulsive symptoms worsen the outcome of early psychotic experiences.

OBJECTIVE: Although there is substantial comorbidity between psychotic disorder and obsessive-compulsive disorder (OCD), little is known about how these clinical phenotypes, and their subclinical extended phenotypes, covary and impact on each other over time. This study examined cross-sectional and longitudinal associations between both (extended) phenotypes in the general population. METHOD: Data were obtained from the three waves of the NEMESIS-study. A representative population sample of 7076 participants were assessed using the composite international diagnostic interview (CIDI) at baseline (T(0)), 1 year later at T(1) and again 2 years later at T(2). RESULTS: At T(0), a lifetime diagnosis of psychotic disorder was present in 1.5% of the entire sample, in 11.5% of the people with any OC symptom and in 23.0% of individuals diagnosed with OCD. OC symptoms at T(0) predicted incident psychotic symptoms at T(2). Similarly, T(0) psychotic symptoms predicted T(2) OC symptoms. The likelihood of persistence of psychotic symptoms or transition to psychotic disorder was higher if early psychosis was accompanied by co-occurring OC symptoms, but not the other way around. CONCLUSION: OCD and the psychosis phenotype cluster together and predict each other at (sub)clinical level. The co-occurrence of subclinical OC and psychosis may facilitate the formation of a more 'toxic' form of persistent psychosis.

[...with psychotic features? An investigation into the delusional nature of convictions in patients with non-psychotic disorders]. / ...met psychotische kenmerken? Een onderzoek naar het waanachtige karakter van overtuigingen buiten het psychosencluster.

BACKGROUND: In certain disorders the boundaries between thoughts, obsessions, overvalued ideas and delusions are not always clearly delineated. AIM: To find out whether delusions can be distinguished from the convictions that often accompany anorexia nervosa, obsessive compulsive disorder (OCD), body dysmorphic disorder (BDD) and hypochondriasis, all of which apparently may involve impaired reality testing. METHOD: The literature was reviewed with the help of PubMed, using as key words 'delusions' in combination with 'hypochodriasis', 'anorexia nervosa', 'body image', 'obsessive compulsive disorder' or 'body dysmorphic disorder'. We also searched the Tijdschrift voor Psychiatrie and references of the literature we used. RESULTS: A number of disorders can probably be classified on a spectrum ranging from non-psychotic to psychotic. For instance, OCD, hypochondriasis, BDD and to a lesser degree anorexia nervosa can all be particularized as 'with good insight', 'with poor insight' or 'with psychotic features'. CONCLUSION: Current practice in DSM-IV is to classify OCD, BDD or hypochondriasis and a delusional disorder as separate entities; this way of classifying seems to be an artefact. Our findings indicate that a dimensional system of classifying psychotic systems is preferable to a categorised system.