OCD is not on the same spectrum as autism or asperger's syndrome. OCD is an anxiety disorder, autism and asperger's are not.

Also, I believe the poster was asking about OCPD, not OCD. The are differences between these two: OCD is an anxiety disorder, OCPD is a personality disorder. While OCD is characterized by obsessions and compulsions, as a manifestation and release of anxiety, OCPD is characterized by obsessions having to do with rules and regulations. The person lacks flexibility and is extremely rigid with routines. Another major differnece is that OCPD is a lifelong way of coping that manifests itself across any situation the person is in-- AND with OCPD the person typically doesn't realize that there is anything wrong with what he/she is doing... not the case for OCD, in which the person realizes that something is wrong.