Anxiety & Sleep Disorders – Anxiety Module

Definition & Diagnostic Criteria for Anxiety

  • Universal experience: Everyone occasionally feels anxious; becomes pathological when persistent and disruptive.
  • Clinical hallmarks
    • Continuous or recurrent anxiety without adequate reason.
    • Multidimensional symptom clusters:
    • Cognitive: persistent worry, racing thoughts.
    • Physiological: tremor, ↑ heart rate (tachycardia), autonomic arousal.
    • Behavioural: avoidance, impaired daily functioning.
  • Key threshold: Anxiety must interfere with day-to-day life to meet disorder criteria.

Neurobiology & Pathophysiology

  • Major CNS neurotransmitters implicated:
    • Noradrenaline (norepinephrine)
    • Serotonin
    • Dopamine
    • GABA\text{GABA} (gamma-aminobutyric acid) – principal inhibitory transmitter.
  • Autonomic nervous system:
    • Parasympathetic division mediates many somatic symptoms (e.g., tremor, palpitations) associated with fight-or-flight physiology.
  • Brain regions
    • Amygdala: heightened reactivity to fear/anxiety cues in anxiety disorders.
    • Limbic system–prefrontal cortex circuit: Dysregulated communication; hyper-activation can be reversed by psychological (e.g., CBT) or pharmacological therapy.
  • Conceptual framing: Anxiety = future-oriented state of fear involving complex cognitive, affective, physiological, and behavioural responses.

Classification of Anxiety Disorders

Common Disorders
  • Specific (simple) phobias
    • Targeted fears: driving, spiders, snakes, etc.
  • Social Anxiety Disorder
    • Persistent social fear beyond normal introversion; occurs without reasonable trigger and disrupts functioning.
  • Separation Anxiety Disorder
    • Seen in children and adults; becomes disorder only when daily life is impaired (e.g., extreme distress persisting beyond contextual norms).
  • Panic Disorder
    • Recurrent, unexpected panic attacks; anticipatory anxiety (e.g., avoiding hospital for fear of elevators despite being at home).
  • Generalized Anxiety Disorder (GAD)
    • Chronic, excessive worry about multiple domains; noted as most common.
Uncommon / Situational Disorders
  • Selective Mutism – failure to speak in specific social situations despite normal language ability.
  • Agoraphobia – anxiety about places where escape might be difficult.
  • Substance/Medication-Induced Anxiety Disorder – directly attributable to pharmacologic agents.
  • Anxiety Disorder Due to Another Medical Condition
    • Examples:
    • Hypothyroidism (↓ thyroid hormones)
    • Hypoglycaemia (low blood sugar)
    • Congestive heart failure
    • Pulmonary embolism
    • Asthma
    • Seizure disorders

Diagnostic & Clinical Pearls

  • Must distinguish normal adaptive anxiety (e.g., brief daycare drop-off distress) from disorder-level anxiety (persistent, impairing).
  • Consider medical and pharmacologic causes before labeling primary psychiatric disorder.
  • Neuroimaging evidence (↑ amygdala activation) supports biological underpinnings and treatment targets.

Treatment Implications (preview)

  • Over-activation of prefrontal-limbic pathways can often be normalized by:
    • Psychological interventions – CBT, exposure therapy.
    • Pharmacological agents – SSRIs, SNRIs, benzodiazepines, etc.
  • Understanding neurotransmitter roles guides medication choice (e.g., GABA-enhancing benzodiazepines for acute relief).