Depression can describe both a mood and an illness.
Major depressive disorder is a clinical syndrome involving mood, neurovegetative functions, cognition, and behaviour.
Lifetime prevalence of approximately 10%.
Risk factors include prior depression and a family history of depression. Recent bereavement, stress, or medical illness may contribute.
For screening and diagnosis, self-rating forms are helpful, but clinical diagnosis is essential. Positive screening should trigger full history, mental status examination, treatment, and follow-up.
Most patients respond well to treatment with medication, talk therapy, or a combination of both.
Suicidal ideation can occur before and peak during treatment, so early and careful follow-up is advised.
Depressive disorders are typically characterised by persistent low mood, loss of interest and enjoyment, neurovegetative disturbance, and reduced energy, causing varying levels of social and occupational dysfunction. Depressive symptoms include depressed mood, anhedonia, weight changes, libido changes, sleep disturbance, psychomotor problems, low energy, excessive guilt, poor concentration, and suicidal ideation. In some cases the mood is not sad, but anxious or irritable or flat.
There is no subthreshold (minor) depression diagnosis in Diagnostic and statistical manual of mental disorders, fifth edition, text revision (DSM-5-TR), but the label has sometimes been applied to diagnose a patient with two to four depressive symptoms, including depressed mood or anhedonia, lasting longer than 2 weeks.
Persistent depressive disorder is characterised by at least 2 years of a depressed mood for most of the day, for more days than not, for at least 2 years.
History and exam
Key diagnostic factors
- presence of risk factors
- depressed mood
- functional impairment
Other diagnostic factors
- weight change
- libido changes
- sleep disturbance
- changes in movement
- low energy
- excessive guilt
- poor concentration
- suicidal ideation
- bipolar disorder excluded
- substance abuse/medication side effects excluded
- medical illness excluded
- schizophrenia excluded
- postnatal status
- personal or family history of depressive disorder or suicide
- oral contraceptives
- co-existing medical conditions
- female sex
- comorbid substance use
- personality disorders
- stressful life events
1st investigations to order
- clinical diagnosis
- metabolic panel
- thyroid function tests
- Patient Health Questionnaire-2 (PHQ-2)
- Patient Health Questionnaire-9 (PHQ-9)
- Edinburgh Postnatal Depression Scale
- Geriatric Depression Scale
- Cornell Scale for Depression in Dementia
Investigations to consider
- 24-hour free cortisol
- vitamin B12
- folic acid
severe depression, non-pregnant: psychotic, suicidal, severe psychomotor retardation impeding activities of daily living, catatonia, or severe agitation
moderate depression, non-pregnant: severe symptoms, significant impairment but no psychotic symptoms, no suicidal ideation, and no severe psychomotor retardation or agitation
mild depression, non-pregnant: low to moderate severity symptoms, partial impairment, no psychotic symptoms, no suicidal ideation, and no psychomotor retardation or agitation
- Adjustment disorder with depressed mood
- Substance-/medication- or medical illness-associated and other depressive disorders
- Bipolar disorder
- Depression in adults: treatment and management
- VA/DoD clinical practice guideline for the management of major depressive disorder
Depression in adults: what is it?
Depression in adults: what treatments work?More Patient leaflets
Geriatric Depression Scale
Depression (any) Screening by a Two Item PHQ-2More Calculators
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