GC164 I Am Depressed Mood Disorders
Mood disorders are a category of mental health conditions—including major depressive disorder, persistent depressive disorder, and bipolar disorder—characterized by significant disturbances in emotional state that impair daily functioning.
I Am Depressed: Mood Disorders
This lecture by Dr. Wai-chi Chan (GC 164) covers the entire clinical landscape of major depressive disorder (MDD) — from distinguishing normal sadness from pathological depression, through epidemiology, DSM-5 diagnostic criteria, aetiology (biological + psychosocial), clinical assessment, differential diagnosis, to the full spectrum of management (pharmacological, psychosocial, physical, dietary). This is a core psychiatry lecture that is directly tested in Fourth Summative exams via MCQs, SAQs, and minicases. [1]
Big Idea: Depression is extraordinarily common (5% of adults worldwide), a leading cause of disability, and a major contributor to suicide. Yet it is treatable — with antidepressants, psychotherapy, exercise, and physical treatments like ECT and TMS. The clinical challenge is recognizing it (presentations vary enormously, especially in the young and elderly), differentiating it from other psychiatric and medical conditions, and choosing the right management.
How it fits into exams: Expect questions on DSM-5 criteria (the 9 symptoms, the "≥5 of 9, including ≥1 core" rule), screening questions for depression (PHQ-2), differential diagnosis (medical causes, bipolar, adjustment disorder, persistent depressive disorder), first-line pharmacotherapy (SSRIs), indications for ECT, and suicide risk assessment.
Is depression always pathological? Mood fluctuations in response to disappointment, frustration and losses in everyday life are usually short-lived. Natural despondency can have an important survival function, resulting in reorientation and maturation. [1]
This is a critical conceptual distinction. Everyone feels sad sometimes. Normal sadness:
- Has an identifiable trigger (loss, frustration)
- Is proportionate to the trigger
- Is self-limiting (days to a few weeks)
- Does not significantly impair function
- Can serve adaptive purposes (introspection, recalibration)
Major depressive disorder is different because:
- Symptoms are severe (DSM-5 uses words like "marked," "significant")
- They impair adaptation and are often disabling
- When enduring, depression impairs function at work, school, and in the family [1]
Why This Matters
Examiners love asking you to differentiate normal grief/adjustment from MDD. The key discriminators are severity, duration (≥2 weeks for MDD), number of symptoms (≥5/9), functional impairment, and the presence of certain features like suicidal ideation, psychomotor changes, or psychotic symptoms that are never "normal."
WHO: 5% of adults suffer from depression worldwide. Approximately 280 million people worldwide have depression. Female:male ratio is ~2:1. [1]
| Statistic | Value | Source |
|---|---|---|
| Global lifetime prevalence (high-income) | 14.6% | Bromet et al. 2011 [1] |
| Global 12-month prevalence (high-income) | 5.5% | Bromet et al. 2011 [1] |
| Female:male ratio | ~2:1 | [1] |
| HK 1-week prevalence mixed anxiety & depression | 6.9% (~1 in 14) | Lam et al. 2015 (HKMMS) [1] |
| HK 1-week prevalence depressive episode | 2.9% | Lam et al. 2015 [1] |
Why is depression more common in women? Postulated reasons include: (1) greater readiness to report symptoms; (2) misdiagnosis as alcohol-related disorder in men; (3) social disadvantages; (4) female hormones may sensitize the brain to stress effects. [3]
Depression is a leading cause of total DALYs — it featured prominently in GBD 2016 data as one of the leading causes of disability globally. [1]
3. Impact of Depression
Depression increases non-suicidal mortality. 72% of 61 reports demonstrated positive association. RR = 1.2–4.0. [1]
Possible mediators (important for understanding why depression kills even without suicide):
- Behavioural risk factors: poor treatment adherence, inactivity, ↑ alcohol consumption
- Biological risk factors: altered thrombogenesis (depression → platelet activation → cardiovascular events)
- Subclinical/prevalent disease: especially cardiovascular disease [1]
Over 700,000 people commit suicide every year. Depression raises suicidal risk 20-fold. Suicide was the cause of death in 6% of patients with an affective disorder. [1]
| Key Finding | Detail |
|---|---|
| Suicide risk attributable to depression | 20-fold increase |
| Long-term suicide risk in depression (Sweden, 54–64y follow-up) | 6.0% |
| HK adults 15–59: Population-attributable risk of suicide from MDD | 27% (even with non-disease social risk factors) |
| HK elderly ≥60: % suicide subjects with psychiatric problems | 86%, commonest = MDD |
Among the psychiatric problems, major depression was the commonest diagnosis in elderly suicide in Hong Kong. [1]
Exam Trap
Students underestimate the mortality of depression. It is not just about suicide — depression independently increases all-cause mortality through cardiovascular and other mechanisms. When asked about "complications of depression," always include both suicide AND increased medical mortality/morbidity.
In some younger people, the first obvious sign may be loss of interest in friends, decline in school performance, self-injury or bulimia or drug use. In some older people, symptoms may mimic dementia — deterioration of cognitive functioning and self-care. In some tragic cases, symptoms may be masked until the person is found dead by suicide. [1]
This is critical because depression does NOT always present as someone saying "I'm depressed":
| Age Group | Atypical Presentation |
|---|---|
| Children/Adolescents | Irritable mood (DSM-5 allows this), school decline, social withdrawal, self-harm, eating disorders, substance use |
| Elderly | Pseudodementia — cognitive decline + poor self-care mimicking dementia. Key differentiator: pseudodementia patients often complain about their memory (insight preserved), onset is more acute, and there may be "don't know" answers rather than confabulation [2] |
| General medical | Somatic complaints (fatigue, pain, GI symptoms) masking underlying depression, especially in Chinese populations (somatization) [4] |
5. DSM-5 Diagnostic Criteria for Major Depressive Disorder
Major Depressive Disorder requires at least 2 weeks' duration, with 5 or more of the following symptoms present, at least 1 of which must be either (1) depressed mood or (2) markedly diminished interest/pleasure. [1]
| # | Symptom | Detail from Lecture | Why It Matters |
|---|---|---|---|
| (1) | Depressed mood | Most of the day, nearly every day. Subjective (feels sad, empty, hopeless) or observed (appears tearful). In children/adolescents: can be irritable mood. | Core symptom — at least one of (1) or (2) must be present |
| (2) | Markedly diminished interest or pleasure (anhedonia) | In all or almost all activities, most of the day, nearly every day | Core symptom — this is the PHQ-2 screening question |
| (3) | Significant weight change | >5% body weight in a month, or ↓/↑ appetite nearly every day. In children: failure to make expected weight gain | Captures both weight loss AND weight gain (atypical depression) |
| (4) | Insomnia or hypersomnia | Nearly every day | Insomnia = typical; hypersomnia = atypical |
| (5) | Psychomotor agitation or retardation | Observable by others (not just subjective) | Must be objectively observable — important exam point |
| (6) | Fatigue or loss of energy | Nearly every day | Most common somatic complaint |
| (7) | Feelings of worthlessness or excessive/inappropriate guilt | May be delusional. Not merely self-reproach about being sick | When guilt becomes delusional → severe depression with psychotic features |
| (8) | Diminished ability to think/concentrate, or indecisiveness | Nearly every day | Contributes to pseudodementia picture in elderly |
| (9) | Recurrent thoughts of death/suicidal ideation | Not just fear of dying. Includes recurrent suicidal ideation ± plan ± attempt | Always assess — critical for risk stratification |
Symptoms cause clinically significant distress or impairment in social, occupational, or other important areas of functioning. The episode is not attributable to substance or another medical condition. Not better explained by schizoaffective disorder, schizophrenia, etc. Absence of previous manic or hypomanic episode. [1]
Critical Exam Point
The ABSENCE of previous manic or hypomanic episode is part of the diagnostic criteria for MDD. If there has EVER been a manic/hypomanic episode, the diagnosis is bipolar affective disorder — current depressive episode, NOT MDD. This is one of the most commonly tested discriminators. [1]
Specifiers include: course (single vs. recurrent), severity (mild/moderate/severe/with psychotic features/remission), and other specifiers: anxious distress, mixed features, melancholic features, atypical features, mood-congruent vs. mood-incongruent psychotic features, catatonia, peripartum onset, seasonal pattern. [1]
| Specifier | Key Features | Clinical Significance |
|---|---|---|
| Melancholic | Pervasive anhedonia, worse in morning (diurnal variation), early morning awakening, psychomotor changes, excessive guilt, significant anorexia/weight loss | Better response to biological treatments (TCAs, ECT) |
| Atypical | Mood reactivity preserved, overeating, oversleeping, leaden paralysis, rejection sensitivity | Classically better response to MAOIs; poorer response to TCAs [3] |
| Psychotic | Delusions and/or hallucinations. Mood-congruent (guilt, worthlessness, disease, death, punishment) vs. mood-incongruent | Mood-incongruent psychotic features → consider schizoaffective disorder |
| Peripartum onset | Onset during pregnancy or within 4 weeks postpartum | Critical for O&G exam questions — see 2024 MCQ Q14 [7] |
| Seasonal pattern | Onset autumn/winter, recovery spring/summer (recurrent episodes only) | Postulated to relate to daylight duration → bright light therapy |
| Catatonia | Psychomotor retardation → mutism, immobility, waxy flexibility | May need ECT urgently |
Removal of the "bereavement exclusion" — depressive symptoms may be understandable/appropriate to significant loss but clinical judgment is needed. [1]
This is important: previously, DSM-IV said you couldn't diagnose MDD within 2 months of bereavement. DSM-5 removed this because:
- Grief can trigger a true MDD
- Withholding treatment because the depression is "understandable" can be harmful
- Clinical judgment should determine whether grief has evolved into a depressive episode
Dysthymia → persistent depressive disorder (includes both chronic MDD and previous dysthymic disorder). [1]
Two new disorders: Disruptive mood dysregulation disorder (children, persistent irritability + explosive outbursts) and Premenstrual dysphoric disorder (mood symptoms in final week before menses). [1]
ICD-11 cardinal symptoms: depressed mood or diminished interest occurring most of the day, nearly every day, for at least two weeks. Additional symptoms: difficulty concentrating, feelings of worthlessness/guilt, hopelessness, suicidal thoughts, appetite/sleep changes, psychomotor agitation/retardation, reduced energy/fatigue. [1]
The ICD-10 system (still used clinically in HK) uses 3 core symptoms: (1) depressed mood, (2) loss of interest/anhedonia, (3) reduced energy/fatigability — and requires ≥2 core + ≥2 additional for a depressive episode. [3]
| Feature | DSM-5 MDD | ICD-10 Depressive Episode |
|---|---|---|
| Core symptoms | 2 (depressed mood, anhedonia) | 3 (depressed mood, anhedonia, anergia) |
| Total required | ≥5 of 9 (including ≥1 core) | ≥2 core + ≥2 additional |
| Duration | ≥2 weeks | ≥2 weeks |
| Severity grading | Mild/moderate/severe/with psychotic features | Mild (4 total), moderate (6 total), severe (7+ total) |
7. Aetiology
Depressive disorder is caused by a combination of biological, social and psychological factors, which disturb the brain's capacity for stress management. [1]
7a. Biological Hypotheses
Classical "serotonin hypothesis": diminished activity of serotonin pathways plays a causal role. Reserpine (depleted monoamines) produced a depressive state. Diminished monoaminergic activity detected in brains of suicide decedents and bodily fluids of depressed people. [1]
Why this matters: This is the theoretical basis for antidepressant pharmacotherapy. But the lecture explicitly states:
Evidence suggests that the cause of depression is far more complicated than a reduced level of serotonin. [1]
| Monoamine | Role | Evidence in Depression |
|---|---|---|
| Serotonin (5-HT) | Body temperature, sleep/wake, mood, impulse control | Low metabolites in suicide decedents' brains and depressed patients' CSF; reduced serotonin functioning [1] |
| Norepinephrine (NE) | Mood and anxiety levels | Mood symptoms in patients taking propranolol [1] |
| Dopamine (DA) | Motor/mental activity, attention, motivation, pleasure (mesolimbic reward pathway) | Diminished dopaminergic neurons in suicidal decedents with depression [1] |
Besides monoamines, abnormalities in glutamate, GABA, and substance P have been detected in patients with depression. [1]
Volume reduction and decreased glial cells in subgenual cortex, reduced hippocampal size. [1]
HPA axis dysregulation, lower estradiol (women) and testosterone (men), decreased T3 and TSH, diminished BDNF level. [1]
BDNF Connection
Brain-Derived Neurotrophic Factor (BDNF) supports neuronal survival and plasticity. Diminished BDNF → impaired neuroplasticity → depression. This is also why exercise is antidepressant — it normalizes BDNF levels. [1]
7b. Psychosocial Hypotheses
Early environment: parental separation, physical/sexual abuse, non-caring or overprotective parenting. Lack of supportive networks. Stress and trauma: long-term difficulties, recent life events (especially entrapment and humiliation). Personality: sociotropy, neuroticism. [1]
Cognitive distortions include: [1]
| Distortion | Chinese | Explanation |
|---|---|---|
| Selective abstraction | 斷章取義 | Focusing on a detail, ignoring the bigger picture |
| Overgeneralisation | 以偏概全 | Drawing general conclusions from a single incident |
| Personalisation | 過度自責 | Relating external events to oneself without justification |
| Arbitrary inference | 妄下判斷 | Drawing conclusions without evidence, or even against evidence |
These cognitive distortions are the targets of Cognitive Behavioural Therapy (CBT).
Loss of an 'object', insecure attachments. [1]
8. Assessment
History (including medical and medication history), mental state examination, use of standardised instruments, physical examination and investigation to rule out medical conditions. [1]
Basic: CBP, R/LFT, thyroid function test. Others if indicated: blood alcohol level, blood/urine toxicology screen, HIV test, cosyntropin (ACTH) stimulation test (for Addison disease), EEG (for epilepsy), CT/MRI (for organic brain syndrome or hypopituitarism). [1]
| Investigation | Purpose |
|---|---|
| CBP | Anaemia (fatigue), infection |
| RFT | Renal failure (uraemic encephalopathy) |
| LFT | Hepatic encephalopathy |
| TFT | Hypothyroidism is a classic medical mimic of depression |
| Blood alcohol, toxicology | Substance-induced depression |
| HIV | HIV-related depression |
| ACTH stimulation | Addison's disease |
| CT/MRI brain | Organic cause (tumour, NPH, stroke) |
| EEG | Epilepsy (especially temporal lobe epilepsy) |
HAM-D, MADRS, PHQ-9, BDI, CES-D. Special groups: Geriatric Depression Scale, Cornell Scale for Depression in Dementia, Edinburgh Postnatal Depression Scale. Useful but NOT diagnostic — should not substitute for clinical diagnosis. [1]
PHQ-2 Screening
The PHQ-2 asks two questions corresponding to the two core DSM-5 symptoms:
- "In the past month, have you been bothered by little interest or pleasure in doing things?"
- "In the past month, have you been bothered by feeling down, depressed, or hopeless?"
This is the most valid screening tool for depression in primary care — directly tested in 2023 MCQ Q80. [6]
9. Differential Diagnosis
Adjustment disorder with depressed mood, manic episode with irritable mood or mixed episodes, persistent depressive disorder, anxiety disorder, substance/medication-induced depressive disorder, mood disorder due to another medical condition. [1]
| Condition | Key Differentiator from MDD |
|---|---|
| Adjustment disorder | Onset ≤3 months of stressor; does NOT meet full MDD criteria; resolves within 6 months of stressor cessation [3] |
| Persistent depressive disorder (dysthymia) | Depressive symptoms NOT meeting MDD criteria for ≥2 years [1] |
| Bipolar disorder — depressive episode | History of ≥1 manic/hypomanic episode |
| Mixed anxiety-depressive disorder | Very common in primary care (6.9% HK); neither depression nor anxiety criteria fully met |
| Substance-induced | Temporal relationship with substance use/withdrawal |
| Schizoaffective disorder | Concurrent schizophrenic + mood symptoms for ≥2 weeks; psychotic symptoms can occur outside mood episodes [3] |
Depression can be associated with medical conditions: [1]
| Category | Examples |
|---|---|
| Neurological | Epilepsy, Parkinson's, dementia, MS, Huntington's, CVD, migraine |
| Endocrine | Hypothyroidism, hyperthyroidism, Cushing's, Addison's, prolactinoma, hyperparathyroidism |
| Drug-related | Reserpine, methyldopa, steroids, sex hormones, H2 blockers, sedatives, chemotherapy, alcohol/cocaine/cannabis abuse |
| Infectious | Mononucleosis, HIV, Hepatitis C, Lyme disease, syphilis |
| Neoplastic | Pancreatic cancer (classic association with depression) |
| Chronic diseases | CAD, type 2 DM |
| Others | Chronic pain, psychosomatic conditions, OSA |
Classic Exam Trap
Reserpine and methyldopa are the classic antihypertensives that cause depression. Pancreatic cancer is the classic malignancy associated with depression. Hypothyroidism is the single most important medical mimic to rule out — hence TFT is a basic investigation. [1]
10. Management
Though changes in monoamines constitute only part of the aetiological picture, the monoamine systems provide the most accessible treatment avenue. [1]
| Class | Examples | Mechanism |
|---|---|---|
| TCAs (non-selective monoamine reuptake inhibitors) | Amitriptyline, imipramine, nortriptyline, clomipramine, dothiepin | Block reuptake of 5-HT + NE (+ anticholinergic, antihistaminic, α-blocking effects → side effects) |
| Tetracyclic | Mianserin | Similar to TCA |
| SSRIs | Fluoxetine, paroxetine, sertraline, citalopram, escitalopram, vortioxetine | Selectively block serotonin reuptake |
| SNRIs | Duloxetine, venlafaxine, desvenlafaxine | Block serotonin + norepinephrine reuptake |
| NDRIs | Bupropion | Block norepinephrine + dopamine reuptake |
| MAOIs/RIMAs | Tranylcypromine, phenelzine, isocarboxazid, selegiline, moclobemide | Inhibit monoamine oxidase (irreversible or reversible) |
| Melatonergic | Agomelatine | MT1/MT2 agonist + 5-HT2C antagonist |
| Others | Trazodone, mirtazapine | Mirtazapine: NaSSA (α2 antagonist → ↑NE and 5-HT release + antihistaminic → sedation/weight gain) |
Key Evidence (Cipriani et al. 2018 Network Meta-Analysis)
More effective: agomelatine, amitriptyline, escitalopram, mirtazapine, paroxetine, venlafaxine, vortioxetine (ORs 1.19–1.96). More tolerable: agomelatine, citalopram, escitalopram, fluoxetine, sertraline, vortioxetine (ORs 0.43–0.77). [1]
Older antidepressants (TCAs, MAOIs) are associated with significant adverse events and drug-drug interactions. There is marked inter-individual variation in tolerability. Choice determined by clinical circumstances, particularly physical comorbidity and concomitant medications. [1]
First-Line Antidepressant Choice
In clinical practice, SSRIs (especially escitalopram, sertraline, fluoxetine) are first-line because they combine good efficacy with superior tolerability and safety in overdose compared to TCAs. The Cipriani meta-analysis is the landmark evidence supporting this. [1]
CBT and interpersonal therapy are highly effective in mild and moderate depression. As many as 85% of patients receiving both antidepressants AND psychotherapy achieve remission. [1]
| Therapy | Core Approach |
|---|---|
| Interpersonal Therapy (IPT) | Problems understood in interpersonal context: facilitate grieving, encourage role transition, explore interpersonal disputes, improve interpersonal skills [1] |
| Cognitive Behavioural Therapy (CBT) | Monitor/evaluate/modify negative dysfunctional thoughts and distorted perceptions. Use cognitive techniques (list pros & cons, examine evidence). Increase activity scheduling [1] |
| Problem-Solving Therapy | Improve ability to deal with everyday problems: identify problems → brainstorm solutions → evaluate effectiveness → best solution [1] |
| Supportive Therapy | Facilitate affect expression, highlight positives, offer empathy, therapeutic optimism, empathic listening [1] |
Systematic review: pooled SMD = -0.40 for exercise vs. control. Inverse association between duration of intervention and magnitude of effect. Mechanisms: normalise BDNF, change neurotransmitter functioning (serotonin, endorphin), improve psychological/social wellbeing. [1]
Tai Chi RCT in HK: 12-step sitting Tai Chi for caregivers with depressive symptoms → well tolerated, reduced depressive symptoms. [1]
10d. Physical Treatments
Where prompt action is needed e.g. strongly suicidal. Side effects: headache, confusion, memory impairment. Also consider need for anaesthesia, costs, inconvenience, stigma. [1]
Indications for ECT:
- Severe depression with strong suicidal risk
- Depression with psychotic features
- Catatonic depression
- Treatment-resistant depression
- When rapid response is needed (e.g., refusing food/fluids)
- Peripartum depression when medications are concerning
Non-invasive. Creates a potent (~1.5T) but brief (µs) magnetic field stimulating nerve tissue. Patient awake and alert. Limited side effects. Suitable for medically unwell patients who cannot tolerate antidepressants or ECT. [1]
Monotherapy: remission rate 4× sham. Adjunct: 58% responded, 37% remitted. FDA-approved for depression. [1]
Healthy diet may help though no specific diet proven to relieve depression. Antioxidants (blueberries, oranges, carrots, nuts), complex carbohydrates (whole grains) for calming effect, protein-rich foods (turkey, tuna, chicken) boost alertness, Mediterranean diet as source of B vitamins. [1]
Omega-3 fatty acids: EPA rather than DHA as the effective component. Can be monotherapy as well as adjunct therapy. [1]
| Severity | First-Line Management |
|---|---|
| Mild | Psychotherapy (CBT, IPT), exercise, psychoeducation, watchful waiting |
| Moderate | SSRI + psychotherapy; combined is superior to either alone |
| Severe without psychosis | SSRI (or SNRI/mirtazapine) + psychotherapy; consider ECT if treatment-resistant or suicidal |
| Severe with psychotic features | Antidepressant + antipsychotic; ECT especially effective |
| Treatment-resistant | Augmentation (lithium, atypical antipsychotic), switch antidepressant class, ECT, TMS |
| Strongly suicidal/catatonic | ECT is first-line |
The PHQ-2 (first two items of PHQ-9) is the most validated brief screen:
- "In the past month, have you been bothered by little interest or pleasure in doing things?" (anhedonia)
- "In the past month, have you been bothered by feeling down, depressed, or hopeless?" (depressed mood)
These map directly onto the two core DSM-5 symptoms. A positive screen requires full assessment.
This was directly tested in 2023 Fourth Summative MCQ Q80 — the answer was option B ("little interest in doing things"), as it targets the core symptom of anhedonia. [6]
86% of elderly suicide subjects in HK suffered from psychiatric problems, most commonly major depression. [1]
Always assess suicide risk in any depressed patient. Key factors to ask about:
- Suicidal ideation (passive → active)
- Plan (method, access to means)
- Intent (desire to die, hopelessness)
- Protective factors (reasons for living, social support, dependents)
- Risk factors: male sex, older age, living alone, substance abuse, previous attempt, comorbid psychiatric illness, chronic medical illness, recent loss/humiliation, unemployment, unmanageable debt [1]
In the presence of non-disease-related social risk factors (unemployment and unmanageable debt), current MDD independently accounted for 27% of the population-attributable risk of suicide. [1]
Exam Intelligence
| Trap | Correct Understanding |
|---|---|
| "Depression is just low mood" | Must have ≥5/9 symptoms including ≥1 core, for ≥2 weeks, with functional impairment |
| Diagnosing MDD when there is past mania | If ANY past manic/hypomanic episode → bipolar disorder, not MDD |
| Missing medical causes | Always check TFT (hypothyroidism), and consider drug-induced depression (reserpine, methyldopa, steroids) |
| PHQ-9 = diagnostic | Rating scales are useful but NOT diagnostic — should not substitute for clinical diagnosis [1] |
| Psychomotor agitation/retardation is subjective | DSM-5 requires it to be observable by others |
| Bereavement exclusion still applies | Removed in DSM-5. You CAN diagnose MDD during bereavement if criteria are met |
| ECT is last resort | ECT is first-line when prompt action needed (strongly suicidal, catatonic, treatment-resistant) |
| All antidepressants are equally effective/tolerable | Cipriani meta-analysis shows differences — escitalopram, mirtazapine, vortioxetine among most effective AND tolerable |
| Dysthymia = mild depression | Dysthymia (persistent depressive disorder) = chronic depressive symptoms NOT meeting MDD criteria for ≥2 years; different from a mild depressive episode |
A man with low mood, lack of motivation, early morning wakening, hopelessness — the most likely psychopathology is Delusion of Guilt (Answer A). This tests understanding that in severe depression, guilt can become delusional. [5]
Past Paper Questions
Stem: "You are the family physician. Mr. Lee, 45 years old, complains of 'tiredness.' (a) Name four differential diagnoses for fatigue. (4 marks) (b) Name four symptoms to elicit to confirm/exclude your differentials. (4 marks) (c) History does not suggest physical cause. Suggest two questions to screen for possible depression. (2 marks)"
Answer:
- (a) Depression, hypothyroidism, anaemia, diabetes mellitus (or: malignancy, sleep disorder, chronic fatigue syndrome)
- (b) Low mood/anhedonia (depression), cold intolerance/weight gain (hypothyroid), polyuria/polydipsia (DM), pallor/dyspnoea on exertion (anaemia)
- (c) "In the past month, have you been bothered by feeling down, depressed, or hopeless?" and "In the past month, have you been bothered by little interest or pleasure in doing things?" (PHQ-2 questions)
Rationale: Part (c) directly tests the PHQ-2 screening questions — the two core DSM-5 symptoms of depression. [8]
Stem: "A 35-year-old man complained of a low mood, lack of motivation, early morning wakening and hopelessness about the future. His work performance has deteriorated significantly and was therefore laid off. He was socially withdrawn. Which of the following is the MOST LIKELY psychopathology? A. Delusion of Guilt B. Delusion of Love C. Formal thought disorder D. Grandiose delusion"
Answer: A. Delusion of Guilt
Rationale: This patient has severe depression. The question asks about psychopathology — in severe depression with psychotic features, delusion of guilt (mood-congruent) is the most likely psychotic symptom. Delusion of love (erotomania) and grandiose delusion are features of mania. FTD is a feature of schizophrenia. [5]
Stem: "Ms. Cheng, 25-year-old, referred for psychiatric assessment. Low mood and anxious for 2 months, poor sleep and appetite. No psychosis. Premorbid personality: cheerful, sociable. (a) Name one psychiatric classification system. (2 marks) (b) List four reasons to classify mental disorders. (4 marks) (c) Name two differential diagnoses. (4 marks)"
Answer:
- (a) DSM-5 or ICD-11 (or ICD-10)
- (b) Aid communication between clinicians; guide treatment decisions; facilitate research; predict prognosis
- (c) Major depressive disorder; adjustment disorder with depressed mood (or: mixed anxiety-depressive disorder, generalized anxiety disorder)
Rationale: Duration is only 2 months and she has both low mood and anxiety — MDD and adjustment disorder are the top differentials. If symptoms don't meet full MDD criteria and there's an identifiable stressor, adjustment disorder is likely. [9]
Stem: "A 22-year-old nursing student presents with headaches for 10 months after her mother's sudden death. The family doctor suspects depression and wants a quick screen. Which question is MOST VALID? A. Poor appetite B. Little interest in doing things C. Difficulty with anxiety D. Trouble concentrating"
Answer: B. Little interest in doing things
Rationale: This is the PHQ-2 anhedonia question — one of the two core symptoms of MDD and the most validated single screening question. The other options are associated symptoms but not core screening items. [6]
Stem: "A 36-year-old, G1P1, delivered 4 weeks ago. LSCS for failed induction. Low mood, guilt about not caring for baby well due to wound pain. Fleeting suicidal thoughts about jumping. Wound healing well. What is the MOST LIKELY diagnosis? A. Normal reaction to wound pain B. Postpartum depression C. Puerperal blues D. Puerperal psychosis"
Answer: B. Postpartum depression
Rationale: Puerperal blues occurs in the first 2 weeks and is self-limiting. This is 4 weeks postpartum with persistent low mood, guilt, and suicidal ideation — meeting criteria for postpartum depression. Puerperal psychosis would involve psychotic symptoms (delusions, hallucinations). Normal reaction would not include suicidal ideation. [7]
High Yield Summary
Depression is common (5% globally, 2.9% in HK), affects women 2× more than men, and is a leading cause of disability and suicide. DSM-5 requires ≥5 of 9 symptoms (including ≥1 core: depressed mood or anhedonia) for ≥2 weeks, with functional impairment, not due to substance/medical cause, and NO history of mania/hypomania. Key changes from DSM-IV: bereavement exclusion removed, dysthymia renamed persistent depressive disorder, two new disorders (DMDD, PMDD). Aetiology is biopsychosocial — monoamine hypothesis provides treatment avenue but is oversimplified. Always check TFT and rule out medical causes. First-line treatment: SSRI + psychotherapy (CBT/IPT). ECT is first-line for strongly suicidal or catatonic patients. TMS is FDA-approved, non-invasive, suitable for medically unwell. Exercise normalizes BDNF and has moderate antidepressant effect (SMD -0.40). Always assess suicide risk — depression accounts for 27% of population-attributable suicide risk in HK adults. Screening: PHQ-2 (anhedonia + depressed mood) is the most valid quick screen.
Active Recall - Mood Disorders: Depression
[1] Lecture slides: GC 164. I am depressed Mood disorders.pdf [2] Senior notes: Maksim Medicine Notes.pdf (Geriatrics - Dementia section) [3] Senior notes: Ryan Ho Psychiatry.pdf (Ch 7 Mood Disorders) [4] Lecture slides: Seminar 2 - Psychopathology - Dr Simon SY Lui_1_9_2025.pdf [5] Past papers: 2020 Fourth Summative Assessment MCQ paper.pdf (Q93) [6] Past papers: 2023 Fourth Summative MCQ.pdf (Q80) [7] Past papers: 2024 Fourth Summative MCQ.pdf (Q14) [8] Past papers: 2018 Fourth Summative SAQ.pdf (Q10) [9] Past papers: 2021 Fourth Summative SAQ.pdf (Q3)
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