Which of the following is the poor prognostic factor for OCD?
**Core Concept**
OCD (Obsessive-Compulsive Disorder) is a psychiatric disorder characterized by recurrent, intrusive thoughts (obsessions) and repetitive behaviors (compulsions). The prognosis of OCD varies among individuals and is influenced by several factors.
**Why the Correct Answer is Right**
The presence of **comorbid depression** is a significant poor prognostic factor for OCD. Studies have shown that individuals with OCD who also experience depression have a poorer response to treatment, longer duration of illness, and increased risk of suicidal behavior. Depressive symptoms can also mask the effectiveness of OCD treatment, leading to a delayed diagnosis and treatment of depression.
**Why Each Wrong Option is Incorrect**
**Option A:** **Age of onset** is not a direct prognostic factor for OCD. However, an early age of onset may be associated with a more chronic course of the illness.
**Option B:** **Family history** of OCD is a risk factor for developing OCD, but it is not a prognostic factor for treatment outcome or illness severity.
**Option C:** **Residual symptoms** after treatment are a poor prognostic factor for OCD, but they are not as significant as comorbid depression.
**Clinical Pearl / High-Yield Fact**
When assessing a patient with OCD, it is essential to screen for comorbid depression, as it can significantly impact treatment outcomes and prognosis.
**Correct Answer: D. Comorbid depression is a poor prognostic factor for OCD.**