Master Psychiatry
for PLAB 1

Core Concepts

Psychiatry employs a biopsychosocial model, recognizing the interplay of biological (genetics, neurotransmitters), psychological (thoughts, emotions, coping), and social (environment, relationships, culture) factors in mental health. Key neurotransmitters include Serotonin (mood, anxiety, sleep), Dopamine (reward, motivation, psychosis), Noradrenaline (alertness, fight-or-flight), and GABA (inhibition, anxiety). Essential legal frameworks in the UK are the Mental Health Act 1983 (MHA), governing compulsory admission and treatment for mental disorder where there's significant risk to self or others, and the Mental Capacity Act 2005 (MCA), which presumes capacity and guides decision-making for those lacking it, prioritizing their best interests.

Clinical Presentation

• Depression: Core symptoms (present for ≥2 weeks): low mood, anhedonia, reduced energy/fatigue. Associated: sleep disturbance, appetite changes, poor concentration, guilt/worthlessness, psychomotor changes, suicidal ideation.
• Anxiety Disorders:
  • Generalized Anxiety Disorder (GAD): Excessive, uncontrollable worry about multiple events/activities for ≥6 months, with ≥3 associated physical symptoms (e.g., restlessness, fatigue, muscle tension, sleep disturbance).
  • Panic Disorder: Recurrent unexpected panic attacks (discrete periods of intense fear with ≥4 physical/cognitive symptoms, e.g., palpitations, sweating, shortness of breath, fear of dying/losing control). Often with agoraphobia (fear of situations where escape is difficult).
  • Specific Phobia: Marked fear/anxiety about a specific object/situation (e.g., heights, animals, needles), leading to avoidance.
  • Social Anxiety Disorder: Marked fear/anxiety about social situations where the individual is exposed to possible scrutiny by others.
  • Obsessive-Compulsive Disorder (OCD): Obsessions (recurrent intrusive thoughts/images/urges causing distress) and/or Compulsions (repetitive behaviors/mental acts performed to neutralize obsessions or reduce distress).
  • Post-Traumatic Stress Disorder (PTSD): Exposure to actual/threatened death, serious injury, or sexual violence. Symptoms (≥1 month): intrusive memories, avoidance, negative alterations in cognitions/mood, hyperarousal (e.g., exaggerated startle, sleep disturbance).
• Psychosis (e.g., Schizophrenia): ≥1 month of ≥2 symptoms (one must be delusions, hallucinations, or disorganised speech).
  • Positive Symptoms: Delusions (fixed, false beliefs), Hallucinations (perceptions in absence of external stimulus, often auditory), Disorganised speech (thought disorder), Grossly disorganised/catatonic behaviour.
  • Negative Symptoms: Affective flattening, Alogia (poverty of speech), Avolition (lack of motivation), Anhedonia, Asociality.
• Bipolar Affective Disorder: Alternating episodes of mania/hypomania and depression.
  • Mania: Abnormally & persistently elevated, expansive, or irritable mood & persistently increased goal-directed activity/energy for ≥1 week, with ≥3 additional symptoms (e.g., grandiosity, decreased need for sleep, pressured speech, flight of ideas, distractibility, excessive involvement in risky activities).
  • Hypomania: Similar but less severe, ≥4 days, no marked functional impairment or psychosis.
• Personality Disorders: Enduring, inflexible patterns of inner experience and behaviour that deviate from cultural expectations, causing distress or impairment. E.g., Borderline PD (emotional dysregulation, impulsivity, unstable relationships, chronic suicidality/self-harm).
• Substance Misuse: Patterns of problematic use leading to significant impairment or distress. Presentation varies by substance (intoxication vs. withdrawal). E.g., Alcohol withdrawal (tremor, sweating, anxiety, seizures, delirium tremens).
• Eating Disorders:
  • Anorexia Nervosa: Restriction of energy intake leading to significantly low body weight, intense fear of gaining weight, disturbed body image.
  • Bulimia Nervosa: Recurrent episodes of binge eating followed by inappropriate compensatory behaviors (e.g., purging, excessive exercise) at least once a week for 3 months. Weight often within normal range.

Diagnosis (Gold Standard)

Diagnosis in psychiatry is clinical, based on a comprehensive history, mental state examination (MSE), collateral history (from family/carers with consent), and application of diagnostic criteria (ICD-11 or DSM-5). Crucially, organic causes (e.g., medical conditions, substance effects, neurological disorders) must always be excluded first via physical examination, blood tests (FBC, U&Es, LFTs, TFTs, B12/folate, glucose, toxicology screen), and imaging (CT/MRI head) if indicated. No single 'gold standard' lab test exists for primary psychiatric disorders.

Management (First Line)

Management employs a holistic biopsychosocial approach, prioritizing safety and shared decision-making. NICE guidelines are central.

• Depression:
  • Mild: Watchful waiting, guided self-help (CBT-based), exercise.
  • Moderate/Severe: Antidepressants (SSRI e.g., Sertraline, Citalopram) AND high-intensity psychological therapy (e.g., CBT).
  • Severe/Refractory: Electroconvulsive Therapy (ECT).
• Anxiety Disorders:
  • GAD, Panic, Social Phobia: CBT (exposure therapy key for phobias) AND/OR SSRIs.
  • OCD: High-dose SSRIs AND CBT with Exposure and Response Prevention (ERP).
  • PTSD: Trauma-focused CBT, EMDR, or SSRIs (Sertraline, Paroxetine).
• Psychosis (Schizophrenia):
  • Acute: Oral atypical antipsychotic (e.g., Olanzapine, Risperidone) +/- short-term benzodiazepine for agitation.
  • Maintenance: Atypical antipsychotic. Psychological therapies (CBT for psychosis, family intervention).
  • Refractory: Clozapine (requires close monitoring due to agranulocytosis risk).
• Bipolar Affective Disorder:
  • Acute Mania: Antipsychotic (e.g., Olanzapine, Quetiapine) +/- Lithium/Valproate.
  • Acute Depression: Quetiapine, Olanzapine-Fluoxetine combination, Lamotrigine, or Lithium. Antidepressants used with caution (risk of mood switch).
  • Maintenance: Mood stabilizers (Lithium - monitor levels, Valproate - teratogenic, Lamotrigine, Carbamazepine).
• Personality Disorders: Psychotherapy is primary (e.g., Dialectical Behaviour Therapy (DBT) for Borderline PD). Pharmacotherapy targets comorbid symptoms (e.g., SSRIs for depression).
• Substance Misuse:
  • Detoxification: Supervised withdrawal (e.g., benzodiazepines for alcohol, opioid substitution therapy for opioids).
  • Relapse Prevention: Psychosocial interventions, pharmacological (e.g., Naltrexone, Acamprosate for alcohol; Buprenorphine/Naloxone for opioids).
• Eating Disorders:
  • Anorexia: MANTRA (Maudsley Anorexia Nervosa Treatment for Adults), CBT-ED, Family-Based Treatment (for adolescents). Refeeding syndrome risk.
  • Bulimia: CBT-ED, Fluoxetine (high dose).

Exam Red Flags