An article on OCD discusses what disorders are related enough to group together.
OCD in some respects differs from the other anxiety disorders in terms of phenomenology, brain circuitry, family history, and treatment response. Instead, it shares features of basic etiology, brain circuitry, and genetics with a group of other related or OCD spectrum disorders. These may include Tourette’s syndrome; body dysmorphic disorder; autism and the developmental disorders; eating disorders, including binge-eating disorder; Huntington’s disorder and Parkinson’s disorder; pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections (PANDAS) or Sydenham’s chorea; some of the impulse control disorders; some of the newly emerging compulsive and impulsive disorders; and obsessive-compulsive personality disorder. At issue for the DSM-V is also whether the hoarders that are currently considered a subtype of OCD should be thought of as distinct from OCD and placed into one of the obsessive-compulsive spectrum disorders.
It’s from 2005, but this is the first time I’ve run into spectrum notions that weren’t bipolar or autism-related.
I wish there were some way of sitting in on DSM-V committee meetings. I’d love to watch the process by which people attempt to arrive at a working compromise on What Things Are.