Health anxiety in obsessive compulsive disorder and obsessive compulsive symptoms in severe health anxiety: An investigation of symptom profiles.

Severe health anxiety (SHA) shares features with obsessive-compulsive disorder (OCD) and in recent years there has been a debate as to whether the two disorders may represent two facets of the same condition. Few studies have however investigated the overlap and differences in symptom profiles between the disorders. The primary aim of the present study was to investigate these aspects using one sample of participants with a principal diagnosis of SHA and one sample of participants with a principal OCD diagnosis. The second aim was to examine differences in improvement trajectories on measures of health anxiety and OCD symptoms in patients with SHA receiving treatment with exposure and response prevention. We compared persons participating in clinical trials with a principal diagnosis of SHA (N=290) to persons with a principal diagnosis of OCD (n=95) on measures of health anxiety, OCD symptoms, and depressive symptoms. A subsample of SHA participants (n=99) received exposure and response prevention (ERP) for SHA over 12 weeks and was assessed at baseline and post-treatment. The results showed large and significant differences between SHA and OCD patients on measures of health anxiety (ds=2.99-3.09) and OCD symptoms (ds=1.64-2.14), while they had equivalent levels of depressive symptoms (d=0.19, 95% CI [-0.04, 0.43]). In the SHA sample 7.6% had comorbid OCD, and in the OCD sample 9.5% had SHA. For participants with a principal diagnosis of SHA, ERP led to large reductions of health anxiety, but effects on OCD symptoms were small to moderate. Among participants with comorbid OCD, effect sizes were large on measures of health anxiety and moderate to large on OCD measures. We conclude that SHA and OCD are separate psychiatric disorders with limited overlap in symptom profiles.