Behavioural characteristics and psychiatric disorders

The behavioural phenotype of fragile X syndrome is often the presenting feature. Key characteristics include anxiety, avoidance and hyperarousal.

Anxiety in males with fragile X syndrome tends to present with behavioural disorders, while anxiety in females is more often internalised, presenting as gaze aversion, avoidant behaviours, social anxiety or panic disorders. See Anxiety disorder.

Hyperarousal may present with anxiety-like symptoms and be triggered by sensory defensiveness (ie an overly sensitive response to stimuli including environmental factors); see Hyperarousal and sensory defensiveness.

Other behavioural characteristics and psychiatric disorders that can occur in people with fragile X syndrome may include:

• social problems (eg shyness, social anxiety, aggression or self-injurious behaviour)—in all age groups but more common in postpubertal males
• executive function defects (eg difficulty with planning, organising, memory)—significant in higher functioning males and females
• attention problems with or without hyperactivity
• autism spectrum disorder—occurs in 30%.