Panic Disorder, Agoraphobia, and Generalized Anxiety Disorder

1. Overview & Epidemiology

Fear vs anxiety (Gajdos lecture, examiner loves this opener):

Fear = response to a known, external, definite threat.
Anxiety = response to a threat that is unknown, internal, vague, or conflictual.
Normal anxiety exists and is adaptive (facilitator); pathological anxiety is a debilizer that impairs thinking, perception and learning.

Burden / prevalence (National Comorbidity Study, per UD slides):

1 in 4 persons meets criteria for ≥1 anxiety disorder; 12-month prevalence ≈ 17.7%.
~Half of all GP attenders meet criteria for an anxiety disorder → anxiety is the commonest psychiatric presentation in primary care.
Women lifetime prevalence 30.5% vs men 19.2% (≈ 1.5–2:1 female predominance across the group).
Prevalence decreases with higher socioeconomic status.

Disorder	Lifetime prevalence	Sex	Typical onset	Defining feature
Panic disorder	~1.5–3.5%	F:M ~2:1	Late teens–mid 30s	Recurrent unexpected panic attacks + anticipatory anxiety
Agoraphobia	~1–2%	F > M	20s–30s	Fear of situations hard to escape; can occur with OR without panic
GAD	~2–5%	F:M ~1.5–2:1	Adulthood (chronic)

Exam-anchored epidemiology facts (PSY 1.4):

Lifetime prevalence of panic attacks in disorders other than panic disorder ≈ 10% (panic attacks are a transdiagnostic specifier).
Agoraphobia is more common in females.
Social phobia is the most common type of phobia.
FALSE: agoraphobia is associated with panic disorder in all cases — agoraphobia can exist without panic.

Classification — what counts as an anxiety disorder (PSY 2.44, 4.134):

ICD-10 (F40–F48 "Neurotic, stress-related and somatoform disorders"): F40 phobic anxiety disorders, F41 other anxiety disorders (incl. panic, GAD), F42 OCD, F43 reaction to severe stress/adjustment, F44 dissociative, F45 somatoform.
Panic, agoraphobia, GAD ARE anxiety disorders. Somatic symptom disorder is NOT — it is a somatoform disorder.
Panic syndrome belongs to the anxiety disorders, not personality, affective, or "vegetative" disorders (even though it is dominated by vegetative symptoms).