As with other intrusive, unpleasant thoughts or images, some disquieting sexual thoughts at times are normal, but people with OCD may attach extraordinary significance to the thoughts.
For example, obsessive fears about sexual orientation can appear to the person with OCD, and even to those around them, as a crisis of sexual identity.
While OCD has been considered a homogenous disorder from a neuropsychological perspective, many of the putative neuropsychological deficits may be due to comorbid disorders.
Furthermore, some subtypes have been associated with improvement in performance on certain tasks such as pattern recognition (washing subtype) and spatial working memory (obsessive thought subtype).
Subgroups have also been distinguished by neuroimaging findings and treatment response.
Obsessive–compulsive disorder (OCD) is a mental disorder where people feel the need to check things repeatedly, perform certain routines repeatedly (called "rituals"), or have certain thoughts repeatedly. The standard assessment tool for OCD, the Yale–Brown Obsessive Compulsive Scale (Y-BOCS), has 13 predefined categories of symptoms. A meta analytic review of symptom structures found a four factor structure(grouping) to be most reliable.
These groups are sometimes viewed as dimensions or clusters that may reflect an underlying process.