Depression

A chronic relapsing organic brain disease with biological, psychological and social causes ('stress-vulnerability model'). DSM-5 divides depressive disorders into major depressive disorder (MDD), disruptive mood dysregulation disorder, persistent depressive disorder (PDD/dysthymia — chronic mild depression ≥2 years not meeting MDD criteria), and premenstrual dysphoric disorder. Present in at least 17% of GP attenders; 12-month prevalence 5%, lifetime risk 15%. Moderate-severe depression is as disabling as congestive heart failure, and it is the leading cause of disability for all conditions, both sexes, in Australia and worldwide.

• Use a symptom checklist as part of assessment — practical in general practice
• Key screening questions: 'In the past month, have you been bothered by feeling down, depressed or hopeless?' and 'In the past month, have you often been bothered by little interest or pleasure in doing things?'
• Further assessment questions: What do you think is the matter? Do you feel down in the dumps? Do you have any good times? Has anything changed in your life? How do you sleep — do you wake early? What time of day do you feel worst? Where would you put yourself between 0-100%? Have you felt hopeless? Do you brood about the past? What is your energy/appetite like? Are you as interested in sex as before? Do you feel guilty about anything? Do you feel life is worthwhile? Has the thought of ending your life occurred to you? Do you cry when no one is around (especially useful in children)?
• Enquire about substance use/abuse, anxiety, psychosis, manic/hypomanic episodes, intimate partner violence, bereavement, postpartum depression — screen for past/current mania before starting an antidepressant
• Assessment has four parts: characterising the symptom profile; calibrating severity/chronicity (rating scales); corroborating comorbidities and context; considering coping styles and social/financial/occupational consequences — often spread over multiple consultations

• Abuse (physical, sexual or emotional)
• Divorce or separation; relationship stress (home, work, school)
• Death of a loved one; traumatic life events
• Loss of employment / financial stress
• Life transitions (e.g. children moving out); social isolation/loneliness
• Illness, especially unexpected and life-changing
• Substance abuse (drugs, alcohol)
• Specific medications: tranquillisers, interferon, anticonvulsants, oestrogens, beta blockers
• Genetics plays a role but is not an absolute determinant

Routine screening is recommended (Beyond Blue guidelines) given high prevalence. Depression scales: K10 (distress score), DASS 21/42 (depression and anxiety symptoms), PHQ-2. Perinatal: Edinburgh Postnatal Depression Scale (EPNDS), at least once, ideally both antenatally and postnatally. Screening investigations to consider: FBE, TFTs, U&Es, vitamins B/D, folate, blood glucose, urine toxicology, CT or MRI.

• DSM-5 MDD: at least 5 of 9 symptoms, with anhedonia and/or depressed mood, present for ≥2 weeks — depressed mood; anhedonia; sleep change (increased/decreased); guilt/worthlessness; decreased energy; impaired or increased concentration; change in appetite/weight; psychomotor retardation or agitation; recurrent suicidal ideation
• Excluding criteria: any previous mania/hypomania, or attributable to a psychotic disorder, substance, or medical condition
• In children, irritability may be more prominent than sadness; somatic complaints (poor sleep, not enjoying meals, poor concentration, low self-esteem) are common; can present as antisocial behaviour or separation anxiety (e.g. school refusal)

Ask about suicidal thoughts, plan, lethality, means, past history, and suicide of a family member/peer. The SAD PERSONS index gives a structured score; >7 represents very high risk demanding referral to an acute psychiatric service. Suicide is the 13th leading cause of death in Australia overall (10th in males); ~75% of suicide deaths are male; median age of suicide is the early-to-mid 40s.

Important differential/organic diagnoses to exclude: malignancy (especially lung, brain, pancreas, blood/lymphatics), early dementia, congestive cardiac failure, endocrine disorders (e.g. thyroid disease), menopause, liver and renal failure, infections (e.g. mononucleosis), neurological disease (e.g. MS, Parkinson disease), adverse medication effects, anaemia, SLE, and cerebrovascular disease.

• FBE — Screen for anaemia, infection
• TFTs — Exclude thyroid disease as an organic cause
• U&Es — Baseline / exclude metabolic cause
• Vitamin B12, vitamin D, folate — Exclude deficiency states presenting with mood/energy change
• Blood glucose — Exclude diabetes as a contributing/comorbid factor
• Urine toxicology — Screen for substance use
• CT or MRI brain — If an organic/structural cause is suspected (e.g. early dementia, malignancy)

• K10 — Distress screening score
• DASS 21 / 42 — Depression and anxiety symptom severity
• PHQ-2 / PHQ-9 — Depression screening/severity
• Edinburgh Postnatal Depression Scale (EPNDS) — Perinatal depression screening — antenatal and postnatal

• SET A PACE model: Safety, Education, Therapeutic relationship → Assessment (characterise, calibrate, corroborate, consider) → PACE (Psychological therapy, Antidepressant treatment, Combination, ECT), purposefully prioritising psychological treatment first in the acronym
• Initial priority questions: is the patient a suicide risk? Does the patient require inpatient assessment? Is referral to a specialist psychiatrist indicated?
• Safety must be continually reassessed at each consultation
• The choice of treatment matters less than persisting with it — 'not so much what you do but that you keep doing it'; best outcomes come from a strong therapeutic alliance and shared decision-making that accounts for patient preference

• Mild depression: psychological therapy
• Moderate depression: psychological therapy and/or antidepressants (medication benefit in moderate depression is roughly equivalent to psychological therapies such as CBT/IPT — both around 20% more likely to achieve remission than placebo)
• Severe depression: antidepressants, consider adding psychological therapy to maintain remission; consider psychiatric review and ECT (medication is more effective than psychological therapy alone in severe depression)

• Basic psychological treatments for all patients: advice on lifestyle changes, problem solving, guided self-help, structured supervised exercise, supportive counselling
• More structured therapies (CBT, interpersonal therapy) for selected patients, delivered by appropriately trained clinicians — including computer-based CBT programs
• Actively enquire about complementary/alternative therapy use — nearly half of Australians have used one in the past 12 months, but none is evidence-supported, though some (e.g. St John's wort) warrant further evaluation; St John's wort interacts with HIV medicines, warfarin, digoxin, anticonvulsants, oral contraceptives and triptans, and different preparations vary in active compound content

• If no response evident in the first 2 weeks, or an inadequate response by 6 weeks, the medication is unlikely to work for this patient — a treatment change is recommended, with a washout period before trying a second agent
• Close monitoring early in treatment; weekly monitoring may help
• If remission is not achieved in 3 months, consider a second opinion and continue active treatment
• Continue antidepressant medication for a minimum of 12 months after remission for an initial episode, and 2-3 years for subsequent episodes or those at high relapse risk
• Relapse risk factors: residual depressive symptoms; ≥2 prior episodes in the past 5 years; ≥3 prior episodes; history of severe/prolonged depression (especially with psychosis or attempted suicide); comorbid medical problems; life stressors

When ceasing medication, withdrawal reactions are common — gradual withdrawal by halving the dose each week may help reduce these.

1. 1. Establish safety, educate the patient, and build the therapeutic relationship (SET) alongside a structured assessment (A) — these run throughout, not just at the start
2. 2. Offer psychological therapy ± an antidepressant depending on severity (see Who to treat)
3. 3. If an antidepressant is used, an SSRI is a reasonable first choice for most patients; mirtazapine and reboxetine are also suitable first-line alternatives
4. 4. If an inadequate response at 6 weeks, switch agent (after a washout period) rather than persisting
5. 5. Combining antidepressants, or augmenting with lithium or an antipsychotic, should only be done with psychiatrist supervision
6. 6. Reserve ECT for severe or treatment-resistant depression, administered under psychiatrist supervision

One specific drug-related emergency to recognise in anyone on a serotonergic agent.

• Often underdiagnosed — presentation can be atypical and less expressive, and patients may be ashamed/reluctant to admit it; a change in sleep pattern can be a useful clue
• Agitated depression is the most frequent type in the aged; features may include histrionic behaviour, delusions and disordered thinking
• Medical illness is an important precipitant; depression may be misdiagnosed as dementia or psychosis
• More prone to medication side effects (especially nausea, dizziness, falls, hyponatraemia) and tend to have only a modest antidepressant response — use a low initial dose and slow increase; psychological therapies are useful but underused
• Antidepressant prescribing rates in Australians over 80 are higher than any other age group

• Sadness is common; true depression is less common but does occur — helplessness, worthlessness and despair, with irritability often more prominent than sadness
• Same diagnostic criteria as adults: loss of interest plus sad/irritable mood for ≥2 weeks, often with somatic complaints (poor sleep, reduced appetite, poor concentration, low self-esteem)
• May present as antisocial behaviour or separation anxiety (e.g. school refusal); poor motor skills and family instability are associations
• Suicidal thoughts are common in adolescents but suicide itself is rare before adolescence — engagement and rapport in a youth-friendly environment is critical
• Both parents and doctors tend to be unaware of depression in children

• Affects ~9% of women during pregnancy and ~16% after birth; anxiety is likely as or more common
• Routine screening recommended (Beyond Blue) using the Edinburgh Postnatal Depression Scale, ideally both antenatally and postnatally; explain and seek permission before screening
• Use a family-centred approach: strong therapeutic relationship, open collaborative style, active listening, psycho-education, coordinated follow-up
• Pharmacological therapy can be used in pregnancy, but benefits must be weighed against risks to mother and fetus
• Psychosis in the perinatal period is rare but requires urgent psychiatric assessment; urgent referral if the woman or baby is at risk

• Uncertainty about diagnosis
• Inpatient care obviously necessary
• Severe depression
• Inability to cope at home
• Psychotically depressed (delusions or hallucinations)
• Substantial suicide risk
• Failure of response to routine antidepressant therapy
• Significant menopausal depression
• Associated psychiatric or physical disorders
• Depression in the elderly where diagnosis (including dementia) is doubtful
• Children with apparent major depression

• Explain that antidepressant benefit typically takes 2-6 weeks to become apparent — don't stop early for lack of immediate effect, but a treatment change is appropriate if no response by 6 weeks
• Agree a safety plan with anyone endorsing suicidal thoughts, and arrange reassessment timing appropriate to their risk tier (see Risk assessment)
• Warn that stopping antidepressants abruptly can cause withdrawal reactions — taper gradually (e.g. halving the dose weekly)
• Advise on recognising serotonin syndrome if starting or increasing a serotonergic agent, particularly with polypharmacy
• Arrange consistent follow-up regardless of which treatment is chosen — continuity matters more than the specific modality

• Depression is common, serious and treatable, but often unrecognised — it is 'probably the greatest masquerade in general practice'
• Consider it a chronic relapsing organic brain disease, not simply a reaction to circumstance
• Actively consider somatisation — non-specific presentations (insomnia, prolonged fatigue, headache, nausea, musculoskeletal pain) are common in depression without obvious psychological symptoms; self-report screening tools can help identify these patients
• It frequently coexists with anxiety disorders, stress and substance abuse disorders — screen for these
• Depression is strongly associated with increased suicide risk — this demands explicit risk assessment at every presentation
• The choice of antidepressant matters less than persistence with treatment and a strong therapeutic alliance