Anxiety Disorders

The world's most common mental disorders: generalised anxiety, panic, phobias and social anxiety; what over-active threat circuits look like; and why exposure-based therapy works so well.

Normal anxiety versus a disorder

Anxiety is a normal, useful response to uncertainty and threat. It becomes a disorder when it is out of proportion to the situation, persistent, and interferes with daily life. Anxiety disorders are the most common mental disorders worldwide; the WHO estimated around 301 million people had one in 2019. They usually begin in childhood, adolescence or early adulthood, and are more common in women.

The main types

Generalised anxiety disorder (GAD): persistent, hard-to-control worry about many things, with restlessness, fatigue, tension and poor sleep. Panic disorder: recurrent, unexpected panic attacks — sudden surges of intense fear with pounding heart, breathlessness, dizziness and fear of dying or losing control — and worry about future attacks. Specific phobias: intense fear of particular things such as spiders, heights or needles. Social anxiety disorder: intense fear of being judged or embarrassed in social situations. Agoraphobia: fear of situations where escape might be difficult. (OCD and PTSD were once grouped with anxiety disorders and are now classified separately.)

The brain's alarm system

Brain imaging studies find, on average, heightened amygdala and insula reactivity to threat and reduced regulation by the prefrontal cortex. People with anxiety disorders tend to show attentional biases toward threat and interpret ambiguous situations negatively. Panic attacks may involve misinterpreting normal bodily sensations — a racing heart — as danger, creating a spiral. Anxiety disorders are moderately heritable, and temperament (behavioural inhibition in childhood) and stressful experiences raise risk.

Avoidance: the trap

Avoiding feared situations brings short-term relief but prevents the brain from learning they're safe — so the fear persists or grows.

Treatment

Cognitive behavioural therapy (CBT), especially exposure therapy — gradually and repeatedly facing feared situations — is highly effective, working through fear extinction learning. Medications: SSRIs and SNRIs are first-line; benzodiazepines work quickly but risk dependence and are generally recommended only short-term. Exercise, sleep, reducing caffeine and learning about how anxiety works also help.