Depression

Refers to both negative affect (low mood) and/or absence of positive affect (loss of interest and pleasure in most activities)

Aetiology

Risk factors

• Genetic susceptibility

• Life factors - i.e. social situation e.g. single mums

• Alcohol/drug dependence

• Abuse (sexual or not) - particularly in childhood

• Unemployed

• Previous psychiatric diagnosis

• Chronic disease

• Lack of a confiding relationship

• Urban population

• Post natal period

Pathophysiology

Neurobiology

• Depression may represent the inappropriate expression of evolutionary behaviours

• No clear causative gene identified - individual genes have small effect, and genetic predispositions result from the combination of many different genes (and the environment)

• Depression is associated with changes in brain regions known to be associated with regulation of emotion (but cause vs. effect are not fully understood)

• There are neuroendocrine changes in depression, but it is unlikely these changes are universal and they may be the consequence of illness rather than the cause

Subtypes of depression

• Occasionally paranoid, typically 'mood-congrent' or hypochondiacal

• More common in the elderly

• Often nihilistic delusions - 'I can't eat because my bowels have turned to dust'

• Marked loss of interest or pleasure in activities that are normally pleasurable

• Lack of emotional reactions to events or activities that normally produce an emotional response

• Waking in the morning 2 hours or more before the usual time

• Depression worse in the morning

• Objective evidence of marked psychomotor retardation or agitation (remarked on or reported by other people)

• Marked loss of appetite

• Weight loss (5 % or more of body weight in the past month)

• Marked loss of libido

• Mood reactivity (that is, mood brightens in response to actual or potential positive events)

• Two (or more) of the following:
• Significant weight gain or increase in appetite
• Hypersomnia
• Leaden paralysis (heavy, leaden feelings in arms or legs)
• Long-standing pattern of interpersonal rejection sensitivity (not limited to episodes of mood disturbance) that results in significant social or occupational impairment

• Refers to depression occurring for the first time in later life

• Estimated prevalence about 2% in people aged 65+

• Risk factors include genetic susceptibility, life events (i.e. loss of spouse), social factors (i.e.
  Loneliness, financial hardship) and poor physical health (especially vascular disease)

• Some studies report poorer prognosis than early onset but others don’t

• There may be slower response to antidepressants

Clinical presentation

Symptoms

• Classic triad:
• Anhdonia - loss of enjoyment/pleasure
• Anergia - lack of energy
• Amotivation

• Diurnal variation - typically worse earleier in the day

• Early morning wakening - waking at least 2 hours before the expected/normal waking time

Signs - mental state examination

• May be signs of personal neglect

• Rapport is often difficult to establish

• Reduced eye contact

• Reduced facial expression

• Brow is classically 'furrowed'

• Limited gesturing - movements may be slowed, or absent

• Psychomotor retardation - subjective or objective slowing of thoughts and/or movements

• Reduced rate of speech

• Lower in pitch

• Reduced volume

• Reduced intonation

• Increased speech latencies

• Limited content

• 'Low, 'down', 'miserable', 'unhappy', 'sad'

• Can be described as 'flat'

• Often 'empty', 'black', 'numb'

• Depressed i.e. low

• Reduced range (stays low throughout)

• Limited reactivity - affect doesn't respond or react to changes in subject, context, or emotion

• May report emotional paralysis

• Form: typically normal

• Flow: thoughts are slow, pondering, can be almost absent

• Content: negative, self-accusatory, failure, guilt, low self-esteem, pessimism, delisions, suicidal thinking
• Cotard's syndrome (nihilistic delusions)

• In most cases there is no perceptual disturbance

• Some people report increased self-reference thinking ('people are talking about me'

• Hallucinations can occur - almost always auditory, usually second person and derogatory ('you are a bad person and deserve to die')

• Subjectively, cognition is slow with complaints of poor memory

• 'Pseudo-dementia'

• Typical deficits involve working memory, attention, and planning

• Often compounded by anxiety

• Insight is typically preserved

• People are usually aware of their symptoms - recognition is commonly intact

• However, attribution can often be affected by the illness - symptoms may be blamed on sins, physical illness, personal failings, or weakness

Investigations

Diagnostic criteria

• The depressive episode should last at least 2 weeks

• There have been no hypomanic or manic symptoms sufficient to meet the criteria for hypomanic or manic episode at any time in the individual's life

• Depressed mood - to a degree that is definitely abnormal for the individual, present for most of the day and almost every day, largely uninfluenced by circumstances, and sustained for at least 2 weeks

• Loss of interest or pleasure in activities that are normally pleasurable

• Decreased energy or increased fatiguability

• Loss of confidence or self-esteem

• Unreasonable feeling of self-reproach or excessive and unreasonable guilt

• Recurrent thoughts of death/suicide, or any suicidal behaviour

• Complaints or evidence of diminished ability to think or concentrate, such as indecisiveness or vacillation

• Change in psychomotor activity - with agitation or retardation (either subjective or objective)

• Sleep disturbance of any type

• Change in appetite (increase or decrease) with corresponding weight change

Assessing severity

• Can be assessed using rating scales e.g. HRSD, MADRS

• ICD-10 rates severity according to the number of symptoms
• Moderate depressive episode: two core symptoms and four others
• Severe depressive episode: all three core symptoms and five others

Management

Mild depression

• Antidepressants are not recommended for the initial treatment of mild depression

• Consider watchful waiting, assessing again normally within two weeks

• Consider offering one or more low-intensity psychosocial interventions e.g. CBT

Moderate-severe depression

• Offer antidepressant medication combined with high-intensity psychological treatment (CBT or interpersonal therapy (IPT)
• 1st line antidepressant - SSRI e.g. escitalopram, sertraline, mirtazapine
• If no benefit is felt by 6 weeks, then it is likely the current drug is not suitable for the current patient
• 2nd line - switch SSRI
• 3rd line - consider an antidepressant of a different class that may be less well tolerated e.g. venlafaxine (SNRI), tricyclic antidepressant or an MAOI

• Make an urgent psychiatric referral if the patient has active suicidal ideas or plans, is putting themself or others at immediate risk of harm, is psychotic, severely agitated or self-neglecting

• ECT is typically reserved for the most severe cases in an inpatient setting

Depression in young people

• Mild depression:
• Watchful waiting for 2 weeks
• Group IPT/CBT, non-directive supportive therapy for 2-3 weeks

• Unresponsive or moderate-severe depression:
1. Individual CBT, IPT, family therapy, psychodynamic psychotherapy 4-6 sessions
2. Fluoxetine
3. Sertraline or citalopram