**Question:** "Systematic desensitization" behavioural therapy is used to treat

A. Obsessive-compulsive disorder
B. Social anxiety disorder
C. Generalized anxiety disorder
D. Post-traumatic stress disorder

**Correct Answer:** B. Social anxiety disorder

**Core Concept:**
Systematic desensitization is a type of behavioural therapy that aims to reduce fear and anxiety related to specific phobias or anxiety disorders by exposing patients to the feared situation or stimulus in a controlled and gradual manner. This process helps patients to learn coping techniques to manage their anxiety and eventually overcome their fear.

**Why the Correct Answer is Right:**
Systematic desensitization is most commonly used to treat social anxiety disorder (SAD), also known as social phobia. In SAD, patients experience excessive fear and anxiety in social situations or interactions, often leading to avoidance behaviors. This therapy addresses the cognitive distortions and behavioural avoidance patterns of patients with SAD, helping them to confront their fears and reduce their anxiety levels over time.

**Why Each Wrong Option is Incorrect:**
A) Obsessive-compulsive disorder (OCD) is a psychiatric disorder characterized by persistent and intrusive thoughts, urges, or images leading to repetitive behaviors or mental acts. OCD is not the target of systematic desensitization therapy.

C) Generalized anxiety disorder (GAD) is characterized by excessive, uncontrollable worry and anxiety in various situations, not specifically triggered by a particular stimulus or situation like social anxiety disorder. Systematic desensitization may not be as effective for treating GAD compared to SAD.

D) Post-traumatic stress disorder (PTSD) is a mental health condition caused by exposure to a traumatic event, characterized by intrusive memories, nightmares, and avoidance behaviors. Systematic desensitization is not typically used to treat PTSD as it focuses on reducing fear responses to specific stimuli or situations.

**Clinical Pearl:**
Systematic desensitization is a useful treatment approach for patients with social anxiety disorder, as it helps to reduce fear and anxiety associated with social situations, enabling them to confront and overcome their anxiety. This therapy is a valuable tool in the armamentarium of treatments for anxiety disorders, particularly social anxiety, and demonstrates the importance of selecting the right treatment modality based on the specific mental health condition.