Definition
Anxiety disorders are a category of mental health conditions characterised by persistent, excessive fear or worry that is disproportionate to the actual threat and that disrupts everyday functioning. They include generalised anxiety disorder, panic disorder, social anxiety disorder, specific phobias, and separation anxiety. While occasional anxiety is a universal and adaptive emotion — sharpening attention before a meaningful event — clinical anxiety becomes self-perpetuating, intrusive, and resistant to ordinary reassurance.
Diagnostically, anxiety disorders are distinguished from normal stress by their duration, severity, and the degree to which they interfere with work, relationships, sleep, and physical health. They are among the most common psychiatric conditions worldwide and frequently co-occur with depression, substance use, and chronic medical illness.
Why it matters
How it works
The mechanism involves an interaction between threat appraisal, autonomic arousal, and avoidance behaviour. The brain interprets an ambiguous cue as dangerous, the body mounts a fight-or-flight response, and the person learns to avoid the trigger — which prevents the corrective learning that would otherwise quiet the alarm. Over time, the threshold for triggering the alarm drops and the world feels increasingly unsafe.
Effective treatments target each leg of this cycle. Cognitive-behavioural therapy reworks the threat appraisal step. Exposure therapy rebuilds tolerance for the feared situation. Medication, when indicated, dampens the physiological arousal long enough for new learning to take hold. Lifestyle factors — sleep, exercise, caffeine — modulate the baseline level of arousal the system has to manage.