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L10 Psychological Medicine Depression

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tagspsychologicalmedicine, lecture
aliasesL10 Psychological Medicine Depression

13 min read

Overview

This lecture covers Major Depressive Disorder (MDD) across five linked areas: how common it is and how much harm it causes (epidemiology), how it is classified and diagnosed against DSM-5-TR criteria and distinguished from ordinary sadness and grief, the biological, social and psychological factors (including a Māori health framework, the Meihana Model) that contribute to it, how it is screened for and assessed in practice, and the pharmacological and psychological treatment options available.

Epidemiology

  • Aotearoa NZ 12-month prevalence: 5.7% overall (men 4.2%, women 7.1%); highest among Māori and NZ Europeans (Oakley Browne et al. 2006; NZ Health Survey 2018/19).
  • Prevalence by age group (NZ): 16-24 years 8.7%, 25-44 years 6.3%, 45-64 years 5.2%, 65+ years 1.7% — highest in young adults, falling with age.
  • Global burden (WHO Global Burden of Disease): MDD ranks 2nd of all diseases/disorders by burden (after low back pain); anxiety disorders rank 7th. By % of total DALYs, unipolar depressive disorders rank 1st (9.8%), ahead of ischaemic heart disease (5.9%) and Alzheimer/other dementias (5.8%).
  • Age of onset (Solmi et al. 2021, meta-analysis of 192 studies): most common onset age for depression is 19.5 years (peak ~3.7% share of onsets); schizophrenia peaks slightly later and higher, at 20.5 years (~7%); anxiety disorders show an earlier peak around 15.5 years. Onset of most major mental disorders clusters in the ~15.5-20.5 year window.
  • Prognosis (Scifo et al. 2017): each further depressive episode carries a higher chance of recurrence — roughly 50-60% after a first episode, 70% after a second, 90% after a third, with the illness trajectory moving from acute to subchronic to chronic over successive episodes.
    • Inpatient treatment of a first MDD episode: ~50% achieve full remission within the first year.
    • After discharge, risk of a further recurrent episode: 25% within 6 months, 30-40% within 2 years, 50-75% within 5 years.
  • Impact of MDD: people with depression are 2x as likely to have 1+ chronic disease, 3x as likely to have a pain-related disorder, and 7x as likely to have an alcohol or substance use disorder, together contributing to a loss of nearly 10 years of healthy life. MDD is also strongly associated with marital dissatisfaction/discord and negative parenting behaviours, lower personal earnings and household income, and the highest number of days away from work of any physical or mental disorder.

Diagnosis

  • Two classification systems are used: DSM-5-TR (Diagnostic and Statistical Manual of Mental Disorders, 5th edition, Text Revision — American Psychiatric Association) and ICD-11 (International Classification of Diseases, 11th revision — World Health Organization).
  • Mood disorders split into two top-level categories: depressive disorders and bipolar & related disorders.
  • DSM-5 depressive disorder subtypes: Disruptive Mood Dysregulation Disorder; Major Depressive Disorder (the focus of this lecture); Persistent Depressive Disorder (Dysthymia); Premenstrual Dysphoric Disorder; Substance/Medication-Induced Depressive Disorder; Depressive Disorder Due to a Medical Condition; Other Specified Depressive Disorder (which itself further splits into Recurrent Brief Depression, Short-Duration Depressive Episode, Depressive Episode with Insufficient Symptoms, and Unspecified Depressive Disorder).
  • DSM-5 criteria for MDD (key content):
    • Symptoms present for at least 2 weeks.
    • At least 1 of: depressed mood; anhedonia.
    • At least 5 of the following (cumulative, including the above 2): depressed mood; anhedonia; feelings of worthlessness or guilt; suicidal ideation, plan or attempt; fatigue or loss of energy; sleep decreased or increased; weight or appetite decreased or increased; decreased ability to think/concentrate or indecisiveness; psychomotor retardation or agitation.
    • B) Clinically significant distress or impairment in social, occupational or other important functioning.
    • C) Not attributable to the physiological effects of a substance or another medical condition.
    • D) Not better explained by a schizophrenia spectrum disorder.
    • E) There has never been a manic or hypomanic episode.
    • Specifiers: with anxious distress; with mixed features; with atypical features; with melancholic features; with psychotic features; with catatonia; with seasonal pattern; with peripartum onset.
  • Sadness vs depression: sadness is a healthy emotional reaction and signal of loss, is short-lived, usually does not impair a person’s ability to function productively (unless stress-related), and is often realistic in thought pattern. Depression involves feelings of hopelessness and helplessness, a complex pattern of physiological and psychological symptoms, negatively biased thoughts, and constitutes a mental illness.
  • Grief vs MDD: both can follow significant loss and share intense sadness, rumination, insomnia, poor appetite and weight loss, but differ in pattern. Grief: feelings of emptiness and loss; dysphoria decreases in intensity over days/weeks; dysphoria occurs in waves (“pangs of grief”) triggered by reminders; may be accompanied by positive emotions; self-esteem is preserved; self-derogatory thoughts, if present, usually relate to the deceased; thoughts of death are framed around “joining” the deceased. MDD: persistent depressed mood with an inability to anticipate happiness or pleasure, not tied to specific preoccupations; self-critical/pessimistic ruminations; feelings of worthlessness; suicidal thoughts arising from feeling worthless, undeserving of life, or unable to cope with the pain of depression.

Two slides pose "Is it Depression?" as a discussion prompt — one a cartoon of a person showing elevated, energised affect, the other a set of atypical features (poor memory, inappropriate laughing/crying, aggression, speech disorder, visual/auditory hallucinations, lack of motivation) arranged around a central figure. Neither slide states which features are or are not consistent with depression, or what the intended teaching point of the cartoon is; they are discussion aids only and are not resolved here.

Cause and risk factors

Medications with depressogenic effects (Gupta & Chadda, 2018) — by drug group, with major implicated drugs and depression-relevant adverse effects:

  • Immunomodulators (ciclosporin, corticosteroids, interferon-α, interleukins, isotretinoin, tacrolimus): depression is a more common effect, alongside anxiety and insomnia; mania, psychosis, agitation and delirium are less common.
  • Cardiovascular drugs (ACE inhibitors, alpha/beta blockers, anti-arrhythmics, statins): depression and anxiety are less common effects; fatigue and sleep disorders are more common.
  • Antiretrovirals (efavirenz, ritonavir, zidovudine): depression is a more common effect, with anxiety, fatigue and sleep disorders; euphoria, agitation and psychosis are less common.
  • Anticancer/chemotherapy agents (5-fluorouracil, asparaginase, bortezomib, ifosfamide, vincristine): depression, anxiety and suicidal ideation are less common effects; cognitive impairment, delirium and psychosis are more common.
  • Anticonvulsants (carbamazepine, levetiracetam, phenytoin, topiramate): depression and suicidal ideation are less common effects; sedation, cognitive impairment and agitation are more common.
  • Antitubercular antibiotics (cycloserine, isoniazid, rifampicin): sleep disorders, depression, psychosis and delirium.
  • Oral hypoglycaemics (glimepiride, metformin): anxiety, depression, irritability, cognitive impairment.
  • Other groups with primarily non-depressive psychiatric effects: anti-Parkinsonians (agitation, psychosis, delirium); other antimicrobials such as mefloquine/metronidazole/quinolones (anxiety, insomnia, psychosis); anabolic/androgenic steroids (irritability, mania, psychosis, dependence); antihistaminics (sedation, agitation, psychosis, delirium); analgesics such as aspirin/ibuprofen/indomethacin (sleep disorders, fatigue, agitation, mood changes); anaesthetics/critical care drugs (cognitive impairment, delirium); respiratory drugs (agitation, insomnia, euphoria, delirium); muscle relaxants (anxiety, agitation, mood changes, delirium).

Medical conditions with depressogenic effects: thyroid conditions; cardiac conditions; certain pancreatic conditions; anaemia; vitamin B12 or folic acid deficiency; viral infections (e.g. Lyme disease, post-influenza); dementia.

Biopsychosocial factors of depression:

  • Biological: genetic vulnerability; physical health; disability.
  • Social: loneliness/isolation; lack of social support; family circumstance; relationship issues; adverse childhood events.
  • Psychological: low self-esteem; sensitivity to rejection; rumination; coping skills; hopelessness; negative interpretation bias.

The Meihana Model — a Māori health assessment framework, depicted as a waka (canoe) carrying the patient:

  • Tinana — physical body/symptoms.
  • Hinengaro — emotional and psychological wellbeing.
  • Ratonga Hauora — health services.
  • Wairua — spiritual connectedness.
  • Taiao — physical environment.
  • Whakatere — navigation/treatment, steering the waka.
  • Whānau — support networks.
  • The waka travels through broader contextual currents and winds that shape the journey: marginalisation, colonisation, migration and racism (currents/winds either side), plus tikanga (cultural practice), whenua (connection to land) and whānau roles/responsibilities (ocean currents).
  • Applied to depression specifically: Tinana — chronic conditions, poor nutrition, insufficient sleep; Taiao — life stressors, exposure to trauma, poverty, disconnection from cultural roots; Hinengaro — guilt, hopelessness, negative self-talk, rumination; Wairua — disconnection from spiritual identity/purpose, lack of spiritual support, unresolved spiritual distress.

Assessment

  • Two-question screen (NZ Guideline: Managing Depression in Primary Care): “During the past month, have you often been bothered by feeling down, depressed or hopeless?” and “During the past month, have you often been bothered by little interest or pleasure in doing things?”
  • PHQ-9 (Patient Health Questionnaire-9): 9 symptom items, each rated Not at all / Several days / More than half the days / Nearly every day (scored 0-3) — little interest or pleasure; feeling down, depressed or hopeless; sleep trouble (falling/staying asleep or sleeping too much); fatigue/low energy; poor appetite or overeating; feeling bad about yourself or that you’re a failure/have let yourself or family down; trouble concentrating; moving/speaking so slowly others notice, or the opposite (fidgety/restless); thoughts of being better off dead or of self-harm. A 10th item asks how difficult these problems have made work, home life or getting along with others (Not difficult at all / Somewhat / Very / Extremely).
  • PHQ-9 severity scoring for major depression: 10-14 = mild, 15-19 = moderate, ≥20 = severe; in addition, item 10 should be rated at least “somewhat difficult” for the score to indicate major depression.
  • Further assessment questions, organised under two headings:
    • Present symptoms (mnemonic FIDISO): Frequency; Intensity; Duration; Impact; Suicidal ideation, intention, plans or attempt; Onset.
    • Background: medication; substance use; medical conditions; cultural background; family history; previous interventions.

One slide in the assessment section is a still frame from an embedded interview video with no on-slide caption or text; its content could not be transcribed.

Treatment

  • Pharmacotherapy (e.g. antidepressants, mood stabilisers, stimulants): pros — lower cost, convenience, speed of action; cons — side effects, addiction risk, and that symptom relief alone isn’t a sufficient treatment goal.
  • Psychotherapy (talk therapy), e.g. CBT, Acceptance and Commitment Therapy (ACT), Schema therapy: pros — effectiveness at least equal to medication, produces long-term change, helps manage other life areas (consistent with the biopsychosocial aetiology of depression), limited side effects; cons — cost, time, and dependence on the patient’s motivation and readiness.
  • NICE guidelines recommend combined medication plus CBT, particularly for moderate to severe MDD.

Self-test

  1. State the DSM-5-TR criteria for diagnosing Major Depressive Disorder, including the minimum symptom count and duration.
  2. List the DSM-5 specifiers that can be applied to a diagnosis of MDD.
  3. Distinguish ordinary sadness from clinical depression.
  4. Distinguish grief from MDD, including at least three features that favour grief.
  5. What are the NZ 12-month prevalence figures for depression, and which groups have the highest prevalence?
  6. Where does MDD rank in the global burden of disease, and how does this compare with anxiety disorders?
  7. What is the typical age of onset of depression, and how does it compare with the age of onset of schizophrenia and anxiety disorders?
  8. Describe how the risk of recurrence changes across successive depressive episodes, and how the illness trajectory changes over time.
  9. List four ways in which MDD impacts a person’s life beyond mood symptoms.
  10. List the three domains of the biopsychosocial model of depression, with two example factors from each.
  11. Describe the components of the Meihana Model and how it frames a patient’s wellbeing.
  12. Name two drug groups in which depression is a “more common” adverse effect, and two in which it is “less common.”
  13. List two medical conditions that can produce depressogenic effects.
  14. What are the two standard screening questions for depression, and what do PHQ-9 scores of 12 and 22 respectively indicate?
  15. What does the FIDISO mnemonic cover in a depression assessment?
  16. Compare the pros and cons of pharmacotherapy versus psychotherapy for depression, and state what NICE guidelines recommend for moderate to severe MDD.
  17. A patient presents six weeks after their mother’s death with low mood, poor appetite and insomnia, but reports these feelings come in waves triggered by reminders of her, that she still finds moments of enjoyment with her children, and that she feels no less worthy a person. Is this presentation more consistent with grief or MDD, and why?

Answers

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