Obsessive compulsive disorder is not an anxiety disorder
A comparison of obsessive-compulsive disorder (OCD) and anxiety disorders suggests a new approach to the classification of OCD. The DSM-III-R and DSM-IV, which favour the classification of OCD as an anxiety disorder, underestimate thinking and behavioral disturbances in OCD compared to anxiety which is experienced as nothing more than a state of vigilance or expectation. There are many different biological causes for anxiety and OCD. Anxiety in OCD occurs secondary to mental and behavioral compulsions. The pharmacotherapy of OCD is similar to the treatment of affective disorders in that monoamine oxidase inhibitors (MAOIs) and selective serotonin reuptake inhibitors (SSRIs) are used. In the doses currently given, SSRIs tend to exacerbate panic and anxiety states in OCD. Serotonin is one of the important neurotransmitters implicated in the etiology of both of these psychiatric syndromes. It seems that OCD is not an anxiety disorder but rather a disturbance of thinking and behaviour which only secondarily has a relationship to anxiety. OCD would be better classified under the rubric of an 'obsessional disorder' rather than as an anxiety disorder in a manner similar to the classification of Tourette's syndrome.