8.2 Anxiety Disorders, OCD, PTSD, & Somatic Symptom Disorders
Key Takeaways
- First-line pharmacotherapy for GAD, Panic Disorder, and Social Anxiety Disorder consists of SSRIs or SNRIs combined with Cognitive Behavioral Therapy (CBT); benzodiazepines are reserved for short-term acute rescue only.
- Obsessive-Compulsive Disorder (OCD) requires Exposure and Response Prevention (ERP) behavioral therapy alongside high-dose SSRI therapy or clomipramine.
- Post-Traumatic Stress Disorder (PTSD) diagnosis requires symptoms >1 month across four clusters (intrusion, avoidance, negative mood/cognitions, hyperarousal); prazosin is first-line for PTSD-associated nightmares.
- Somatic Symptom Disorder involves excessive anxiety and persistent thoughts regarding real bodily symptoms, whereas Illness Anxiety Disorder involves fear of having a serious illness with minimal or absent physical symptoms.
- Conversion Disorder (Functional Neurological Symptom Disorder) presents with genuine neurological deficits (e.g., non-epileptic seizures, weakness) incompatible with recognized neuroanatomy, requiring empathetic validation without confronting symptoms as fake.
8.2 Anxiety Disorders, OCD, PTSD, & Somatic Symptom Disorders
Anxiety, obsessive-compulsive, trauma-related, and somatic symptom disorders represent a broad spectrum of psychiatric conditions frequently encountered in primary care. Accurate diagnosis requires distinguishing between normal adaptive anxiety, discrete anxiety syndromes, trauma-related pathology, and physical complaints driven by psychological distress.
Anxiety Disorders Spectrum
Clinical Features & Diagnostic Distinctions
- Generalized Anxiety Disorder (GAD): Excessive, uncontrollable worry about multiple everyday events occurring for at least 6 months, accompanied by $\ge 3$ physical symptoms (restlessness, fatigue, concentration difficulty, irritability, muscle tension, sleep disturbance).
- Panic Disorder: Recurrent, unexpected panic attacks (abrupt surges of intense fear reaching a peak within minutes) followed by at least 1 month of persistent worry about future attacks or maladaptive behavioral changes. Frequently associated with Agoraphobia (fear/avoidance of situations where escape might be difficult, e.g., crowds, public transit).
- Social Anxiety Disorder (SAD / Social Phobia): Marked fear or anxiety about one or more social situations in which the individual may be scrutinized by others (e.g., public speaking, meeting new people), lasting $\ge 6$ months.
- Specific Phobia: Marked, irrational fear of a specific object or situation (e.g., heights, animals, blood-injection-injury) lasting $\ge 6$ months.
Management Principles (CPA & CANMAT Guidelines)
| Condition | First-Line Pharmacotherapy | Non-Pharmacological / Psychological First-Line | Secondary / Adjunct Options |
|---|---|---|---|
| GAD | SSRIs (Escitalopram, Sertraline)<br>SNRIs (Duloxetine, Venlafaxine)<br>Pregabalin | Cognitive Behavioral Therapy (CBT) | Buspirone, Hydroxyzine, Short-term Benzodiazepines |
| Panic Disorder | SSRIs (Fluoxetine, Paroxetine, Sertraline)<br>SNRIs (Venlafaxine) | CBT with Interoceptive Exposure | Short-term Benzodiazepines (e.g., Alprazolam, Clonazepam) |
| Social Anxiety | SSRIs (Escitalopram, Paroxetine, Sertraline)<br>SNRIs (Venlafaxine) | CBT (Individual or Group) | PRN Beta-Blockers (Propranolol 10-40 mg) for performance-only subtype |
| Specific Phobia | Pharmacotherapy generally ineffective | Exposure Therapy (Systematic desensitization / In vivo exposure) | Short-term Benzodiazepine prior to infrequent triggers (e.g., flying) |
CRITICAL EXAM TRAP: Avoid long-term Benzodiazepines for Anxiety Disorders. While benzodiazepines (e.g., lorazepam, alprazolam) offer rapid symptom relief, they carry significant risks of physiological tolerance, dependence, cognitive impairment, motor incoordination (fall risk in elderly), and rebound anxiety upon withdrawal. Use should be strictly limited to acute crises (1–2 weeks max).
Obsessive-Compulsive Disorder (OCD)
Diagnostic Criteria & Clinical Presentation
OCD is defined by the presence of obsessions, compulsions, or both:
- Obsessions: Recurrent, persistent, intrusive, unwanted thoughts, urges, or images that cause marked anxiety or distress (e.g., contamination fears, doubts about locking doors, intrusive harm images). Obsessions are ego-dystonic (recognized by the patient as inconsistent with their personal values).
- Compulsions: Repetitive behaviors (e.g., handwashing, checking, ordering) or mental acts (e.g., praying, counting) performed in response to an obsession to reduce anxiety or prevent a dreaded event.
Evidence-Based Treatment
- First-Line Psychotherapy: Exposure and Response Prevention (ERP) — a specialized form of CBT where the patient is exposed to obsession triggers while refraining from performing compulsive rituals.
- First-Line Pharmacotherapy: High-dose SSRIs (e.g., Sertraline, Fluoxetine, Fluvoxamine, Paroxetine). OCD typically requires higher doses of SSRIs than major depression (e.g., Sertraline up to 200–300 mg daily) and longer trial durations (8–12 weeks) to demonstrate therapeutic response.
- Second-Line / Refractory: Clomipramine (a potent serotonergic Tricyclic Antidepressant; highly effective but limited by anticholinergic and cardiac side effects) or augmentation with low-dose atypical antipsychotics (Aripiprazole, Risperidone).
Post-Traumatic Stress Disorder (PTSD) & Acute Stress Disorder (ASD)
Trauma-Related Symptom Clusters
Both ASD and PTSD occur following exposure to actual or threatened death, serious injury, or sexual violence.
Four Core Symptom Clusters:
- Intrusion: Re-experiencing memories, distressing dreams, flashbacks, or intense psychological reactivity to trauma cues.
- Avoidance: Persistent avoidance of trauma-related thoughts, feelings, places, or people.
- Negative Alterations in Cognition & Mood: Numbing, persistent negative beliefs about oneself/world, distorted blame, detachment, anhedonia.
- Hyperarousal & Reactivity: Irritability, hypervigilance, exaggerated startle response, sleep disturbance, concentration deficits.
Timeline Distinction (High-Yield Exam Point)
- Acute Stress Disorder (ASD): Symptoms present for 3 days to 1 month following trauma exposure.
- Post-Traumatic Stress Disorder (PTSD): Symptoms persist for more than 1 month post-trauma and cause significant functional impairment.
Treatment Strategies
- Psychotherapy: Trauma-focused CBT (Prolonged Exposure, Cognitive Processing Therapy) or Eye Movement Desensitization and Reprocessing (EMDR).
- Pharmacotherapy: SSRIs (Sertraline, Paroxetine) or SNRIs (Venlafaxine) are first-line.
- Nightmare Management: Prazosin (an alpha-1 adrenergic antagonist) effectively reduces PTSD-associated nightmares and sleep fragmentation by suppressing central sympathetic outflow.
- Contraindication: Benzodiazepines are contraindicated in PTSD because they impair natural trauma processing, increase addiction risk, and worsen overall long-term outcomes.
Somatic Symptom & Related Disorders
Somatic symptom disorders involve prominent physical symptoms associated with significant distress and impairment, where psychological factors play a major role in onset or maintenance.
| Disorder | Core Clinical Features | Key Diagnostic Clues | Primary Management Strategy |
|---|---|---|---|
| Somatic Symptom Disorder | One or more distressing somatic symptoms (e.g., chronic pain, fatigue) accompanied by disproportionate, persistent thoughts and anxiety about symptom seriousness. | Symptoms are genuine and distressing to the patient; lasting $\ge 6$ months. | Scheduled regular visits with single primary care physician; avoid unnecessary invasive tests; CBT. |
| Illness Anxiety Disorder | Preoccupation with having or acquiring a serious, undiagnosed illness. Somatic symptoms are absent or minimal. High health anxiety. | Patient performs excessive health-related checking or avoids doctors entirely ("hypochondriasis"). | Empathic therapeutic alliance, CBT, SSRIs if co-morbid anxiety present. |
| Conversion Disorder (FNSD) | One or more altered voluntary motor or sensory functions (e.g., blindness, paralysis, non-epileptic seizures). | Clinical findings demonstrate clear incompatibility between symptom and recognized neuroanatomy (e.g., Hoover sign positive, normal EEG during seizure). | Patient education on functional nature of symptoms, physical therapy, CBT. Do NOT accuse patient of faking. |
| Factitious Disorder | Intentional falsification or induction of physical/psychiatric signs or symptoms. | Primary motivation is to assume the sick role (internal secondary gain). No external reward. | Non-confrontational communication, multidisciplinary team review, psychiatric consultation. |
| Malingering (Not a psychiatric illness) | Intentional feigning or exaggeration of physical or psychological symptoms. | Driven by external incentives (e.g., financial compensation, avoiding military duty/jail, obtaining controlled drugs). | Document objective physical findings; firm, professional boundaries. |
A 29-year-old software developer reports persistent intrusive thoughts that his hands are contaminated by dangerous bacteria, compelling him to wash them with bleach for up to 3 hours daily until they bleed. Which of the following represents the first-line evidence-based non-pharmacological treatment for this condition?
A 34-year-old combat veteran presents with severe intrusive nightmares, hypervigilance, and exaggerated startle response persisting for 6 months after returning from deployment. Which medication is specifically recommended to reduce PTSD-associated nightmares?
A 22-year-old university student is brought to the emergency department after experiencing sudden onset of complete right arm paralysis following an intense argument with her parents. Detailed neurological examination demonstrates normal tone, preserved deep tendon reflexes, and a positive Hoover sign. MRI brain and EMG are normal. What is the most likely diagnosis?