Anxiety is the most common category of psychiatric disorders. It is a normal emotion—a survival mechanism mediated by the limbic system—that becomes pathological when it is disproportionate, persistent, and functionally impairing. This lecture walks from neurobiology → clinical manifestations → specific disorder criteria → management, giving you the scaffolding to diagnose and treat the major anxiety-related disorders: Generalised Anxiety Disorder (GAD), Panic Disorder, Phobic Anxiety Disorders (Specific, Social, Agoraphobia), and Obsessive-Compulsive Disorder (OCD).

1. The role of the limbic system in emotional response and anxiety disorders
2. Clinical manifestation of anxiety symptoms
3. Common anxiety disorders
4. Management of anxiety disorders

• Primary care: Anxiety disorders affect ~1 in 7 adults; > 50% are missed by doctors. Patients often present with somatic rather than psychological complaints ^[3].
• Exam relevance: Anxiety disorders are a recurring topic in Fourth Summative MCQs, EMQs, SAQs, and minicases. The AOS notes flag that "common" diagnoses like anxiety, PTSD, OCD, and adjustment disorder are frequently tested ^[7].
• Related GC lectures: GC 171 (Stress-related & OCD) ^[4], GC 164 (Depression), GC 165 (Sleep), GC 168 (Psychopharmacology), CFB PSY01-04.

The amygdala-based neurocircuit is central to anxiety. ^[1]

Why this matters from first principles: In normal fear, a threatening stimulus is detected by the amygdala → hypothalamus activates the sympathetic nervous system → heart rate ↑, sweating, hyperventilation etc. The prefrontal cortex then evaluates the threat and suppresses the amygdala if the danger is not real. In anxiety disorders, this top-down regulation is impaired—the amygdala is hyperactive, the prefrontal cortex is hypoactive, and the hippocampus fails to properly contextualise safety signals.

Dysregulation of GABA, norepinephrine, and serotonin systems causes anxiety disorder. ^[1]

Psychological symptoms: worrying thoughts, fearful anticipation, irritability, restlessness, sensitivity to noise, difficulty in concentration, subjective poor memory. ^[1]

Why somatic symptoms occur: The autonomic nervous system (sympathetic activation via hypothalamus/brainstem) produces all these physical manifestations. Patients may undergo extensive medical workups (cardiac, GI, respiratory) before anxiety is considered.

Panic Disorder: Severe anxiety attack — palpitation, chest pain, choking sensation, dizziness, fear of dying, losing control, or going mad. ^[1]

Key characteristics:

• Unpredictable & sudden onset — not restricted to any particular situation, no obvious precipitating factor ^[1]
• Recurrent attacks
• Persistent fear of having another attack (anticipatory anxiety)
• Subsequently avoid that situation → may develop phobic symptoms
• May be agoraphobic if attacks occur in various situations ^[1]
• May become demoralised and depressed ^[1]

An abrupt surge of intense fear or intense discomfort that reaches a peak within minutes, and during which time four (or more) of the following symptoms occur: ^[1]

Note: A panic attack is not itself a diagnosis—it is a specifier. The diagnosis of Panic Disorder requires the recurrence criteria below.

1. Recurrent unexpected panic attacks
2. At least one attack followed by ≥1 month of one or both:
   • Persistent concern about having additional attacks or their consequences
   • A significant maladaptive change in behaviour related to the attacks (e.g. avoiding exercise, leaving home)
3. Not due to direct physiological effects of a substance or general medical condition
4. Not better accounted for by another mental disorder

• Depression
• Other anxiety disorders (e.g. agoraphobia)
• Alcohol and drug abuse

Why these DDx matter: Pheochromocytoma causes episodic catecholamine surges that perfectly mimic panic attacks (paroxysmal hypertension, palpitations, sweating, tremor). Thyrotoxicosis causes chronic sympathetic overactivity. Temporal lobe epilepsy can produce feelings of dread and autonomic symptoms. Always exclude organic causes before diagnosing panic disorder.

Phobic Anxiety Disorder: Psychological & somatic manifestation of anxiety occur only in particular circumstances. Avoidance. Anticipatory anxiety. ^[1]

Three types: Specific Phobia, Agoraphobia, Social Phobia ^[1]

Anxiety is provoked in the presence or anticipation of a specific object: Animals, Heights, Thunders, Darkness, Blood etc. Tendency to avoid the stimulus. Severe distress or functional impairment. ^[1]

DSM-5 Criteria [1]

1. Marked fear or anxiety about a specific object or situation
2. Almost always provokes immediate fear or anxiety
3. Actively avoided or endured with intense fear
4. Out of proportion to actual danger and sociocultural context
5. Persistent, typically ≥6 months
6. Causes clinically significant distress or functional impairment
7. Not better explained by another mental disorder

Special note on Blood-Injection-Injury (BII) phobia: Unlike other phobias where the autonomic response is sympathetic activation (tachycardia, hypertension), BII phobia uniquely causes a vasovagal response (initial tachycardia then profound bradycardia and hypotension → fainting). This is why patients with needle phobia actually faint rather than just feel anxious.

Away from home. In crowds or situations they cannot leave easily that provoke anxiety and avoidance: Buses, Trains, MTR, Supermarket, Queue, Hairdresser's chair, Cinema. Need to be accompanied. Severe → Housebound. ^[1]

DSM-5 Criteria [1]

• Marked fear or anxiety about TWO (or more) of five situations:
  1. Using public transportation
  2. Being in open spaces
  3. Being in enclosed places
  4. Standing in line or being in a crowd
  5. Being outside of the home alone
• Fears situations because escape might be difficult or help might not be available
• Almost always provokes fear/anxiety
• Actively avoided, require companion, or endured with intense fear
• Out of proportion, persistent ≥6 months, causes significant distress/impairment
• Not better explained by another mental disorder

Anxious in situations observed, criticized, embarrassment or humiliation. Speak in small group. Introduced to stranger. Eat in public, write in public. Fear of angry, rejecting face, avoid eye-contact. Blushing and trembling. ^[1]

DSM-5 Criteria [1]

1. Marked fear about social situations with possible scrutiny by others
2. Fears acting in a way or showing anxiety symptoms that will be negatively evaluated
3. Almost always provokes fear/anxiety
4. Avoided or endured with intense fear
5. Out of proportion, persistent ≥6 months
6. Causes clinically significant distress/impairment
7. Not attributable to substance or medical condition
8. Not better explained by another mental disorder
9. If another medical condition present, fear is clearly unrelated or excessive

Key point: The fear is specifically about being negatively evaluated by others, not about the situation itself. This distinguishes social phobia from agoraphobia (where the fear is about being unable to escape).

• Depression
• Alcohol and drug abuse
• Panic disorder with agoraphobia

Why avoidance DDx matters: Avoidant personality disorder shows pervasive social avoidance but from a core sense of inadequacy (not discrete fear episodes). Psychosis may cause avoidance due to persecutory delusions. Depression causes withdrawal from activities due to anhedonia, not fear.

Excessive worries and anxiety. Free floating anxiety. Apprehensive expectation. Psychological & somatic manifestation of anxiety occur most of the time. ^[1]

"Free-floating" anxiety means the anxiety is not tied to any particular object, situation, or event—it just "floats" around, attaching to whatever is currently in the person's mind. This distinguishes GAD from phobias (situational) and panic disorder (episodic).

1. Excessive anxiety & worry, occurring more days than not for at least 6 months, about a number of events or activities ^[1]

2. The person finds it difficult to control the worry ^[1]

3. Associated with ≥3 of the following 6 symptoms: ^[1]

4. Causes clinically significant distress & functional impairment ^[1] 5. Not due to direct physiological effects of substance or medical conditions ^[1] 6. Not explained by another mental disorder ^[1]

2/3 of GAD patients have other psychiatric diagnoses ^[1]

• Depression
• Other anxiety disorders (e.g. panic, social anxiety)
• Personality disorder (e.g. anankastic, paranoid, avoidant) — note "anankastic" = obsessive-compulsive personality disorder
• Alcohol and drug abuse

The GAD-7 is a validated 7-item self-report questionnaire. Each item scored 0-3 (not at all → nearly every day). Total score interpretation:

Recurrent, compulsive nature. Thoughts, impulses, images, ruminations or doubts (obsession). Themes: dirt, contamination, aggression, illness, religion. Stereotyped behaviour (compulsion): Checking, cleaning, counting, slowness. Maintained insight & regarded as senseless. Presence of resistance. ^[1]

Key conceptual points:

• Obsessions are ego-dystonic (the patient recognises them as unwanted and distressing—they are NOT delusional)
• Compulsions are performed to reduce the anxiety caused by obsessions, but they are excessive and not realistically connected to preventing the feared outcome
• Insight is maintained — the patient knows these thoughts/behaviours are irrational
• Resistance — the patient tries to resist the obsessions/compulsions but fails

1. Contamination with cleaning 2. Doubt with checking 3. Precision & symmetry with ordering, counting, repeating, hoarding, slowness 4. Religious, sexual, aggressive obsession ^[1]

Obsessions (both required):

1. Recurrent and persistent thoughts, urges, or images that are intrusive and unwanted, causing marked anxiety
2. The individual attempts to ignore, suppress, or neutralize them

Compulsions (both required):

1. Repetitive behaviours (hand washing, ordering, checking) or mental acts (praying, counting) that the individual feels driven to perform
2. Aimed at preventing/reducing anxiety or preventing a dreaded event, but not connected in a realistic way or clearly excessive

Additional criteria:

• Time consuming (> 1 hour/day), or cause marked distress, or functional impairment ^[1]
• Not due to substance
• Not better explained by another mental disorder

1. Presenting complaint: "What brings you in today?" — many present somatically
2. Characterise the anxiety:
   • Onset, duration, course (episodic vs continuous)
   • Triggers (situational → phobia; none → panic disorder; generalised → GAD)
   • Content of worry
3. Associated symptoms: Psychological + somatic
4. Avoidance behaviours: What situations does the patient avoid?
5. Impact on function: Work, relationships, daily activities
6. Comorbidities: Screen for depression (low mood, anhedonia), substance use, suicidal ideation
7. Medical history & medications: Rule out organic causes
8. Family history: Genetic contribution
9. Premorbid personality: Anxious temperament, perfectionism

• Mental state examination (MSE): Appearance (restless, fidgety), mood (anxious), speech (pressured), thought content (worries, obsessions), perceptions (normal in pure anxiety)
• Physical examination: Thyroid (goitre, tremor, tachycardia), cardiovascular (arrhythmia), neurological

• Bloods: TFTs (thyrotoxicosis), glucose (hypoglycaemia), calcium
• ECG: Arrhythmia
• 24hr urinary catecholamines/metanephrines: Pheochromocytoma (if episodic hypertension + anxiety)
• Drug screen: If substance use suspected

Questions 23–27 (Common Psychological Presentations EMQ)

Options: A. Adjustment disorder, B. Bipolar disorder, C. Eating disorder, D. Generalised anxiety disorder, E. Major depressive disorder, F. Obsessive compulsive disorder, G. Panic disorder, H. Post-traumatic stress disorder, I. Substance use disorder, J. Undifferentiated psychological distress

• Q23: "Constant worrying even when there is no specific threat." → Answer: D. Generalised anxiety disorder — Free-floating anxiety about multiple concerns without specific trigger. ^[8]
• Q25: "Recurrent episodes of feeling short of breath as though one cannot get enough air in." → Answer: G. Panic disorder — Recurrent episodic breathlessness mimicking cardiopulmonary disease is classic panic. ^[8]
• Q27: "Constant need to check that the stove is switched off and doors are locked." → Answer: F. Obsessive compulsive disorder — Doubt with checking is one of the four common OCD presentations. ^[8]

Stem: Mrs. Chen, a construction site worker, fell from a rooftop in 2019 causing multiple rib fractures. Since then, she has recurrent shortness of breath and chest tightness when about to resume rooftop work. A doctor told her about panic disorder.

• Q4 (6 marks): "Name three psychiatric symptoms she may have experienced."

  • Markscheme: Fear of dying / losing control / going mad; palpitations; chest pain/tightness; choking sensation; dizziness; sweating; trembling; derealization/depersonalization; paresthesias; anticipatory anxiety. (Any 3 from DSM-5 panic attack criteria + anticipatory anxiety)
  • Discriminator: Note this case has a clear situational trigger (returning to rooftop) — this might actually be better classified as a specific phobia or PTSD rather than "true" panic disorder (which should be unexpected/uncued). However, the question frames it as panic disorder.

• Q5 (7 marks): "Develop a management plan for panic disorder in primary care while waiting for investigation results."

  • Markscheme: (1) Psychoeducation about panic disorder; (2) Reassurance that physical symptoms are not dangerous; (3) Explain the fight-or-flight response; (4) Breathing/relaxation techniques; (5) Consider short-term benzodiazepine if severe; (6) Consider SSRI initiation; (7) Referral to psychiatry/psychology for CBT. ^[11]

Stem: "Characteristic features of a certain disorder include unpredictable attacks, signs reminiscent of myocardial infarction, and anticipatory anxiety, in the absence of severe stress. What is the MOST LIKELY diagnosis?"

Options: A. Agoraphobic disorder, B. Conversion disorder, C. Obsessive-compulsive disorder, D. Panic disorder

Answer: D. Panic disorder — Key discriminators: "unpredictable attacks" (= unexpected, uncued), "signs reminiscent of MI" (chest pain, palpitations), "anticipatory anxiety," and "absence of severe stress" (ruling out stress-related disorders). Agoraphobia would be situational, not unpredictable. ^[12]

Stem: "A 45-year-old woman presents at GOPC for low mood and fatigue for 6 months. She has difficulty falling asleep due to worry about health, muscle tension, weight gain of 5 kg, and loss of concentration. No suicidal ideation. Lives alone, few friends. Which symptom is MOST SUGGESTIVE of depression over GAD?"

Options: A. Difficulty falling asleep, B. Loss of concentration, C. Muscle tension, D. Weight gain

Answer: D. Weight gain — Difficulty falling asleep and loss of concentration occur in both. Muscle tension is more specific to GAD. Weight gain (or significant weight change) is a somatic feature more specific to depression. ^[9]

Stem: "It is not uncommon to have difficulties during interview with patients with anxiety disorder. Which technique would have a NEGATIVE impact during interviewing anxious patients?"

Options: A. Address the anxious feeling, B. Ask specific questions, C. Clarification and explanation, D. Give a diagnostic label

Answer: D. Give a diagnostic label — Labelling can increase stigma and anxiety. The other options are all appropriate interviewing techniques. ^[9]

Stem: "A 27-year-old bank teller presents with 3 months of worry about finances, girlfriend, parents' health, and own health. Trouble sleeping and controlling worries on most days. Restless, cannot sit still. GAD-7 score is 10. What is the severity level of his anxiety?"

Options: A. Mild Anxiety, B. Moderate Anxiety, C. No Anxiety, D. Severe Anxiety

Answer: B. Moderate Anxiety — GAD-7 score of 10 falls in the 10–14 range = Moderate. ^[10]