Depression- clinical features

Epidemiology

• 14-18% lifetime prevalence
• 20% of cases are chronic
• Genetic risk
  • Increased risk if first degree relative affected (3x)
  • Twin studies- MZ (27%) vs DZ (12%)
  • Hereditability of major depression is around 70%
• More common in females than males (2:1) and mean age of onset is 27 years old.

Aetiology

• Onset can be associated with excess adverse life events- mainly exit events (e.g. death/bereavement, separation etc) or negative early experiences e.g. abuse or neglect.

Diagnostic classification

Depressive episodes

• ICD-10 splits depressive episodes into mild, moderate and severe depression +/- the presence of somatic or psychotic symptoms.

Depression

• DSM IV splits depression into just minor and major; ICD-10 splits into mild, moderate and severe.

Clinical Features

Symptoms must be clearly abnormal for the individual concerned, it must persist for more than 2 weeks (without previous history of mood disorder), and it should interfere with normal function to a significant degree.

In moderate depression, there should be 2; and in severe depression, all of the following typical symptoms:

• Low mood to a degree that is definitely abnormal for the patient; present for most of the day; largely uninfluenced by circumstance; and present for at least 2 weeks
• Loss of interest or pleasure in activities that are usually enjoyable (anhydonia)
• Decreased energy or increased fatigue

PLUS >=4 (moderate) or >4 (severe) of:

• Loss of confidence/self esteem
• Unreasonable feelings 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 e.g. indecisiveness
• Changes in psychomotor activity, with agitation or retardation (either objective or subjective)
• Sleep disturbance
• Change in appetite with corresponding change in weight

Severity

Although the diagnosis of severe/moderate/mild depression are made on the number of symptoms, there are various other ways of assessing the severity of depression.

• Rating scales e.g. Hamilton rating scale for depression; Montomery-Asberg depression scale; Beck depressive inventory (NB Beck’s cognitive triad- negative view of self, others and the future)

Subtypes of depression

• Somatic syndrome
• Atypical
• Psychotic depression
• Postnatal depression
• Chronic (treatment-refractory) depression

Progression / Timeline

The 5 ‘R’s’ are a good way of thinking about it:

• Response
• Remission
• Relapse
• Recovery
• Recurrence

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