Which of the following is a common sign of obsessive-compulsive disorder (OCD)?

The presence of intrusive thoughts and repetitive behaviors is a hallmark sign of obsessive-compulsive disorder (OCD). Individuals with OCD often experience persistent, unwanted thoughts (obsessions) that cause significant anxiety or distress. To mitigate this distress, they may engage in specific actions or rituals (compulsions), which are repetitive behaviors designed to reduce the anxiety associated with the obsessions. This cycle of obsessions leading to compulsive actions is central to OCD and differentiates it from other anxiety disorders.

The other options do not accurately reflect the core characteristics of OCD. Increased social engagement is typically not associated with OCD; in fact, many people with OCD may experience social withdrawal due to their symptoms. While avoidance of daily activities can occur in various mental health conditions, it is not a defining feature of OCD specifically. Sudden mood changes may occur in various contexts but are not specific indicators of OCD. Understanding these distinctions helps clarify the nature of obsessive-compulsive disorder and its symptoms.