Can OCD and GAD Occur Together?
Yes, OCD and GAD frequently co-occur, with generalized anxiety disorder being significantly more common in individuals with OCD and their first-degree relatives compared to controls.
Evidence for Comorbidity
The co-occurrence of these disorders is well-established through multiple lines of evidence:
Family study data demonstrates that GAD is significantly more frequent in first-degree relatives of OCD probands compared to control relatives, and this association persists even when the relative does not have OCD themselves, suggesting a shared familial etiology 1
In clinical populations, approximately 94% of patients with GAD report some obsessive-compulsive symptoms, though these are typically less severe than in primary OCD 2
Both disorders share common cognitive vulnerabilities, particularly deficits in attentional control, which are present in both OCD and GAD patients compared to non-clinical controls 3
Symptom Overlap and Distinctions
While these disorders frequently co-occur, important differences exist:
Anxiety symptoms reach similar severity levels in both OCD and GAD, with no significant differences in most anxiety manifestations between the two diagnostic groups 4
Patients with GAD show significantly higher intensity of phobic disorders, conversion symptoms, cardiac autonomic dysfunction, and hypochondria compared to OCD patients 4
Obsessive-compulsive symptoms are more prevalent and more strongly expressed in OCD than in GAD, but the near-universal presence of some OC symptoms in GAD patients (94%) indicates substantial overlap 2
Structural Differences in Symptom Relationships
The relationship between obsessions and compulsions differs between the two disorders:
In OCD, no significant correlation exists between the severity of obsessions and compulsions, whereas in GAD, a significant positive correlation is found between these symptoms 2
In GAD, deficits in attentional control are specifically associated with increased perseverative worry, with trait anxiety mediating this relationship 3
Checking behaviors differ qualitatively: OCD symptoms associate with both object-related and interpersonal checking, while GAD symptoms associate only with interpersonal checking 5
Clinical Implications
When evaluating patients with either disorder:
Screen systematically for the other condition, as the comorbidity is common and may not be identified during routine psychiatric examination 2
Compulsions appear more specific for OCD diagnosis than obsessions, as obsessive thoughts occur across both disorders 2
Factor analyses reveal three similar factors in both OCD and GAD: 'anxiety/depressiveness', 'obsessions', and 'compulsions', though additional distinct factors exist (depressiveness in OCD, separation anxiety in GAD) 4
Shared Familial Risk
Beyond GAD, other anxiety and mood disorders show elevated rates:
Panic disorder, agoraphobia, separation anxiety disorder, and recurrent major depression are all more common in first-degree relatives of OCD probands 1
Only GAD and agoraphobia show increased frequency in OCD relatives independent of whether the relative has OCD, suggesting true shared familial etiology rather than secondary emergence 1
Most comorbid anxiety and affective disorders may emerge as a consequence of OCD or represent a more complex syndrome when they occur together 1