Subthreshold symptoms and obsessive-compulsive disorder: evaluating the diagnostic threshold

In this study we compared subjects with obsessive and/or compulsive symptoms who did not meet all criteria for obsessive-compulsive disorder (OCD) (subthreshold subjects) to subjects with full-blown OCD and also to subjects without obsessions or compulsions.

The data were derived from the Netherlands Mental Health Survey and Incidence Study (NEMESIS), a large representative sample of the general Dutch population (n=7076). Using the Composite International Diagnostic Interview, Version 1.1 (CIDI 1.1), three groups were distinguished: subjects without lifetime obsessions or compulsions (94.2%), subthreshold subjects (4.9%) and subjects with full-blown OCD according to DSM-III-R (0.9%). These three groups were compared on various items, including psychological vulnerability, health and functional status, psychiatric co-morbidity and seeking treatment.

Subthreshold and OCD subjects had similar scores on the majority of the items measured. Thus, there was little difference between subthreshold and OCD subjects in health, functional status, psychological vulnerability and psychiatric co-morbidity. However, OCD and subthreshold subjects scored worse on most of these items when compared to the controls without obsessions or compulsions.

Having obsessions and compulsions is associated with substantial suffering and disability. Most subjects with obsessions and/or compulsions are not diagnosed with OCD according to the DSM-III-R criteria although these subjects generally display similar consequences to full-blown OCD subjects. We recommend that these subthreshold cases receive special attention in the development of DSM-V.