Methodological issues in the design of clinical studies of new drugs for the treatment of obsessive compulsive disorder.
Obsessive Compulsive Disorder (OCD) is increasingly recognised to be relatively common and responsive to some drug treatments (serotonin reuptake inhibitors). Clinical studies utilising recognised diagnostic criteria have identified some relevant negative prognostic factors: early age at disease onset, severe baseline disease, and failure of previous drug treatments all of which reduce the apparent success rates of SRI drugs. Furthermore, patients with comorbid tics seem to respond best to a combination of SRI activity and dopamine blockade. Short term efficacy studies are best performed with a parallel group design and a duration of around 3 months. Long term efficacy studies should probably use the relapse prevention design, with open label responders randomised to double blind continuation or placebo. Does finding has not been properly explored, and any one fixed dose will only be optimal for some patients. Efficacy can be reliably measured using the YBOCs, NIMH-OC and CGI rating scales.
Holland
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