Anxiety Disorders, OCD & PTSD for NEET PG 2026: Diagnosis, SSRI, CBT

The 2015-16 National Mental Health Survey of India put the prevalence of anxiety disorders at around 3 percent and reported a treatment gap of over 80 percent. Stigma, primary-care underdiagnosis, and the bewildering DSM-5 nosology mean these are exactly the topics NEET PG examiners reach for. The 2022 ICD-11 release simplified some categories (separated obsessive-compulsive and related disorders into their own chapter), and the 2023 introduction of zuranolone for postpartum depression changed adjacent pharmacotherapy.

This NEETPGAI deep dive walks through DSM-5 criteria for each anxiety disorder, OCD, and PTSD, the diagnostic instruments (Y-BOCS, PCL-5, GAD-7), pharmacotherapy with SSRIs and SNRIs, the role of buspirone and benzodiazepines, exposure-based psychotherapy, ECT indications, and the India-specific NMHS context. Pair this guide with the common mistakes in psychiatry and the SSRI/antidepressant pharmacology maps for full coverage.

Generalised anxiety disorder (GAD)

DSM-5 criteria

A. Excessive anxiety and worry about multiple events or activities, occurring more days than not for at least 6 months. B. Difficulty controlling the worry. C. Three or more of these somatic symptoms in adults (one in children): restlessness, easy fatiguability, poor concentration, irritability, muscle tension, sleep disturbance. D. Clinically significant distress or impairment. E. Not due to a substance or another medical condition. F. Not better explained by another mental disorder.

Screening and severity

GAD-7 is the standard 7-item screen. Score 5 (mild), 10 (moderate), 15 or above (severe). It is also useful as an outcome measure during treatment.

Treatment

• First-line pharmacotherapy — SSRI (sertraline, escitalopram, paroxetine) or SNRI (venlafaxine, duloxetine). Start low, double or triple over 2 to 4 weeks. Full anxiolytic response takes 4 to 6 weeks. Continue for 12 months after remission to prevent relapse.
• Buspirone — partial 5-HT1A agonist. Useful adjunct or alternative; lacks dependence potential. Slow onset (2 to 4 weeks). Not effective for panic disorder.
• Benzodiazepines — short-term bridging only (clonazepam, lorazepam, diazepam). Avoid in elderly, history of substance use disorder, and pregnancy.
• Psychotherapy — cognitive behavioural therapy (CBT), applied relaxation, mindfulness-based stress reduction.
• Pregabalin — alternative anxiolytic licensed in Europe; useful when SSRI not tolerated.

Panic disorder

DSM-5 criteria

Recurrent unexpected panic attacks (a discrete period of intense fear peaking within minutes with at least 4 of 13 symptoms — palpitations, sweating, trembling, dyspnea, choking, chest pain, nausea, dizziness, chills/heat, paraesthesias, derealisation, fear of losing control, fear of dying), plus at least one of (a) persistent anticipatory anxiety, or (b) behavioural change to avoid attacks, lasting at least one month.

Specifier for agoraphobia (fear of two or more situations where escape is difficult — public transport, open spaces, enclosed spaces, queues, being outside home alone).

Differential diagnosis (the must-rule-out list)

• Cardiac — myocardial infarction, supraventricular tachycardia.
• Endocrine — hyperthyroidism, pheochromocytoma, hypoglycaemia.
• Pulmonary — pulmonary embolism, asthma exacerbation.
• Substance — caffeine, cocaine, amphetamine, alcohol withdrawal.
• Other psychiatric — PTSD flashback, anxious depression.

Treatment

• First-line pharmacotherapy — SSRI (paroxetine, sertraline, fluoxetine) or SNRI. Start at half the GAD starting dose because panic patients are unusually sensitive to early jitteriness from SSRIs.
• Short-term benzodiazepine — clonazepam or alprazolam during acute exacerbation; cross-taper over 4 to 6 weeks.
• Psychotherapy — CBT with interoceptive exposure (deliberate induction of feared physical sensations) is highly effective.

Social anxiety disorder

Marked fear of social situations where the person may be judged. Onset typically in adolescence. Symptoms include blushing, trembling, sweating, and avoidance of public speaking and unfamiliar people.

Treatment — SSRI (paroxetine, sertraline) is first-line. Beta-blocker (propranolol 10 to 40 mg) for performance-only subtype. CBT with social skills training and exposure.

Specific phobia

Marked fear of a specific object or situation (animals, blood-injection-injury, heights, flying, situational, other). Lasts 6 months or more.

Treatment — exposure therapy is the most effective intervention; pharmacotherapy is rarely needed except short-term benzodiazepine for unavoidable encounters (a flight).

Obsessive-compulsive disorder (OCD)

DSM-5 moved OCD out of the anxiety disorders chapter into a new category — obsessive-compulsive and related disorders — alongside body dysmorphic disorder, hoarding disorder, trichotillomania, and excoriation disorder.

DSM-5 criteria

Presence of obsessions, compulsions, or both:

• Obsessions — recurrent intrusive unwanted thoughts, urges, or images that cause marked anxiety; the person attempts to ignore or neutralise them.
• Compulsions — repetitive behaviours (hand washing, ordering, checking) or mental acts (counting, praying, repeating words) performed in response to an obsession.

The obsessions or compulsions are time-consuming (more than 1 hour/day) or cause clinically significant distress or impairment.

Specifier for insight (good or fair, poor, absent or delusional).

Common themes

• Contamination obsessions with washing compulsions.
• Symmetry obsessions with ordering and counting.
• Forbidden or taboo thoughts (sexual, aggressive, religious) with mental compulsions.
• Harm obsessions with checking compulsions.

Y-BOCS (Yale-Brown Obsessive Compulsive Scale)

Gold-standard severity instrument. Ten items, each scored 0 to 4. Total 0 to 40.

• 0 to 7 — subclinical.
• 8 to 15 — mild.
• 16 to 23 — moderate.
• 24 to 31 — severe.
• 32 to 40 — extreme.

Treatment

• First-line psychotherapy — exposure and response prevention (ERP). The patient is exposed to triggers while resisting the compulsion until the anxiety naturally falls (extinction learning). Best-evidence psychotherapy in psychiatry.
• Pharmacotherapy — SSRIs at higher doses than for depression: fluoxetine 60 to 80 mg, sertraline 200 mg, paroxetine 60 mg, fluvoxamine 200 to 300 mg, escitalopram 20 to 30 mg. Allow 10 to 12 weeks for full response.
• Clomipramine — TCA with strong serotonergic action; the most effective single antidepressant in OCD but limited by anticholinergic, cardiac, and seizure-threshold effects. Start 25 mg, titrate to 200 to 250 mg.
• Augmentation strategies — second-generation antipsychotic (risperidone, aripiprazole) for treatment-refractory cases or comorbid tic disorder; adding clomipramine to SSRI; intensive ERP.
• Refractory disease — deep brain stimulation of the ventral capsule/ventral striatum or anterior limb of internal capsule. Cingulotomy and capsulotomy are last-resort neurosurgical options.

Post-traumatic stress disorder (PTSD)

DSM-5 moved PTSD out of anxiety disorders into a new chapter — trauma- and stressor-related disorders — alongside acute stress disorder, adjustment disorder, prolonged grief disorder, and reactive attachment disorder.

DSM-5 criteria (adults)

A. Stressor — exposure to actual or threatened death, serious injury, or sexual violence, by direct experience, witnessing, learning of trauma to a close family member or friend, or repeated occupational exposure to aversive details.

B. Intrusion symptoms (1 or more) — intrusive memories, distressing dreams, dissociative reactions (flashbacks), psychological distress at cues, physiological reactions to cues.

C. Avoidance (1 or more) — avoiding internal reminders (thoughts, feelings) or external reminders (people, places, activities).

D. Negative alterations in cognition or mood (2 or more) — inability to remember key features of the trauma, persistent negative beliefs, distorted blame, persistent fear or guilt, diminished interest, detachment, inability to feel positive emotions.

E. Marked alterations in arousal and reactivity (2 or more) — irritability or anger, reckless behaviour, hypervigilance, exaggerated startle, poor concentration, sleep disturbance.

F. Symptoms last more than one month. G. Clinically significant distress or impairment. H. Not due to a substance or another medical condition.

Specifier for dissociative subtype (depersonalisation, derealisation) and delayed expression (full criteria not met until 6 months after the trauma).

Acute stress disorder

Same exposure plus 9 of 14 symptoms across the same domains, lasting 3 days to 1 month.

Treatment

• First-line psychotherapy — trauma-focused CBT (TF-CBT), prolonged exposure therapy, cognitive processing therapy, or eye movement desensitisation and reprocessing (EMDR). All four have robust evidence.
• Pharmacotherapy — SSRI (sertraline, paroxetine — both FDA-approved) or SNRI (venlafaxine). Slower response than in depression — allow 8 to 12 weeks.
• Prazosin — alpha-1 antagonist for trauma-related nightmares; titrate to 5 to 15 mg at bedtime.
• Avoid benzodiazepines as monotherapy — they may impair extinction learning and worsen long-term outcomes.
• Avoid early debriefing — single-session psychological debriefing immediately after trauma does NOT prevent PTSD and may be harmful.

Pharmacology high-yield points

SSRIs

• Examples — sertraline, fluoxetine, paroxetine, escitalopram, citalopram, fluvoxamine.
• Mechanism — selectively block serotonin reuptake at SERT.
• Common ADRs — GI upset (most common), sexual dysfunction (paroxetine worst), insomnia or somnolence, weight gain or loss, hyponatraemia (SIADH-mediated, especially elderly), QT prolongation (citalopram dose-dependent above 40 mg), bleeding risk on platelets, serotonin syndrome with MAOI or tramadol or linezolid.
• Discontinuation syndrome — flu-like symptoms, dizziness, paraesthesias, electric-shock sensations on abrupt withdrawal, especially paroxetine and venlafaxine (short half-lives). Taper over 2 to 4 weeks.
• Pregnancy — sertraline preferred; paroxetine has been associated with cardiac defects and is avoided in early pregnancy.

SNRIs

Venlafaxine, desvenlafaxine, duloxetine, milnacipran. Add noradrenergic effect; useful in anxiety with chronic pain. Dose-dependent hypertension with venlafaxine above 150 mg.

Buspirone

Partial 5-HT1A agonist. Slow onset (2 to 4 weeks), no dependence, no sedation. Effective in GAD; poor in panic and OCD.

Benzodiazepines

GABA-A allosteric modulators. Useful as bridge therapy. Avoid long-term in anxiety disorders. Watch for dependence (especially short-acting alprazolam), cognitive impairment in elderly, paradoxical disinhibition in dementia, respiratory depression with opioids. Flumazenil is the antidote.

ECT

Indications relevant to this chapter:

• Severe treatment-resistant depression with comorbid anxiety.
• Catatonic features.
• High suicide risk. ECT is NOT first-line for OCD or PTSD but may be considered for refractory severe depression with comorbid OCD; rTMS has emerging evidence for OCD.

NEET PG MCQ traps

1. GAD duration — 6 months minimum (NOT 1 month).
2. PTSD duration — more than 1 month; if 3 days to 1 month, diagnose acute stress disorder.
3. OCD higher SSRI dose — fluoxetine 60 to 80 mg in OCD versus 20 to 40 mg in depression. The trap stem gives an OCD patient on fluoxetine 20 mg with no response — the answer is dose escalation, not switch.
4. Y-BOCS — gold-standard OCD severity tool, 10 items, range 0 to 40.
5. PHQ-9 vs GAD-7 vs Y-BOCS — depression vs GAD vs OCD respectively.
6. Prazosin for PTSD nightmares — alpha-1 antagonist; the trap stem mentions a veteran with combat-related nightmares responsive to a "blood pressure tablet."
7. Avoid benzodiazepines in PTSD — worsens long-term outcome by impairing extinction learning.
8. Single-session debriefing after trauma — DOES NOT prevent PTSD and may harm; this is a public-health PSM-style trap.
9. Hoarding disorder — separate DSM-5 diagnosis from OCD; DSM-IV listed it under OCD.
10. EMDR for PTSD — bilateral eye movements during recall; mechanism still debated, but outcomes equal trauma-focused CBT.
11. Clomipramine — most effective tricyclic in OCD; not first-line because of ADRs.
12. Lifetime risk — anxiety disorders affect roughly one in five Indians during their lifetime per NMHS; women are 1.5 to 2 times more affected than men.

Recent updates and Indian context

• DSM-5 (2013) restructuring — OCD and PTSD removed from the anxiety chapter into separate chapters (obsessive-compulsive and related; trauma- and stressor-related).
• ICD-11 (2022) — adopted similar restructuring; introduced complex PTSD.
• NMHS 2015-16 — point prevalence of common mental disorders 10 percent; anxiety disorders 3 percent; treatment gap above 80 percent.
• National Mental Health Programme (NMHP) — Indian government initiative since 1982; District Mental Health Programme since 1996 emphasises primary-care integration, community-level screening (often via ASHA workers), and referral pathways.
• Mental Healthcare Act 2017 — replaced the 1987 Mental Health Act; right to access mental healthcare, advance directives, decriminalisation of attempted suicide (Section 115), and central mental health authority structure. Frequent PSM-style stem.
• Ayushman Bharat Tele MANAS — 24x7 toll-free mental health helpline launched 2022.
• NMC and FMGE alignment — Indian undergraduate exams emphasise DSM-5 criteria, SSRI dose ranges in OCD, the GAD-7, Y-BOCS, and PCL-5 instruments, and the Mental Healthcare Act 2017 provisions.

Frequently asked questions

What are the DSM-5 criteria for generalised anxiety disorder?

GAD requires excessive anxiety and worry about multiple events for at least 6 months, difficulty controlling the worry, and at least 3 of 6 somatic symptoms (restlessness, fatigue, poor concentration, irritability, muscle tension, sleep disturbance) in adults — only 1 needed in children. The worry causes clinically significant distress or impairment and is not better explained by another disorder or substance.

What is the first-line treatment for OCD?

First-line is exposure and response prevention (ERP), a specific cognitive behavioural therapy that exposes the patient to triggers while preventing the compulsive ritual. Pharmacotherapy with SSRIs at higher doses than for depression (fluoxetine 60 to 80 mg, sertraline 200 mg, fluvoxamine 200 to 300 mg) is added when ERP alone fails or symptoms are severe. Clomipramine is the most effective tricyclic but has more side effects.

How is PTSD diagnosed by DSM-5 criteria?

DSM-5 PTSD requires exposure to actual or threatened death, serious injury, or sexual violence, plus at least one intrusion symptom (flashbacks, nightmares), one avoidance symptom (avoiding reminders), two negative cognitions or mood symptoms, and two hyperarousal symptoms (hypervigilance, exaggerated startle, sleep disturbance). Symptoms must persist beyond one month and cause functional impairment. Acute stress disorder is the equivalent diagnosis if symptoms last 3 days to 1 month.

When are benzodiazepines indicated in anxiety disorders?

Benzodiazepines are useful for short-term relief during a panic attack, severe situational anxiety, and bridging the 4 to 6 weeks before SSRI takes effect. Long-term use is avoided due to dependence, cognitive impairment, paradoxical disinhibition, and rebound anxiety on withdrawal. They are contraindicated as monotherapy in PTSD and OCD because they may worsen avoidance and impair extinction learning.

What is the prevalence of anxiety disorders in India per NMHS?

The 2015-16 National Mental Health Survey of India (NMHS) reported a current prevalence of common mental disorders of 10 percent, with anxiety disorders around 3 percent and depressive disorders around 5 percent. Lifetime prevalence is higher. There is a marked treatment gap — over 80 percent of those with anxiety disorders do not receive any mental health care, mostly due to stigma, low access, and underdiagnosis at primary care.

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Written by: NEETPGAI Editorial Team Reviewed by: Pending SME Review Last reviewed: May 2026