Depression in adults

Depression can describe both a mood and an illness.

Major depressive disorder is a clinical syndrome involving mood, neurovegetative functions, cognition, and behaviour.

Affects 5% to 10% of patients in the primary care setting.

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.[1]American Psychiatric Association. Diagnostic and statistical manual of mental disorders, 5th ed., (DSM-5). Washington, DC: American Psychiatric Publishing; 2013.

Major depressive disorder is characterised by the presence of at least five symptoms and can be classified along a spectrum of mild to severe. Severe episodes may include psychotic symptoms such as paranoia, hallucinations, or functional incapacitation.

Subthreshold (minor) depression is not defined in DSM-5, but 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 (previously known as dysthymic disorder) is characterised by at least 2 years of a major depressive syndrome or subthreshold major depression with three or four depressive symptoms (including hopelessness, which is not a core major depressive symptom) for more days than not.[1]American Psychiatric Association. Diagnostic and statistical manual of mental disorders, 5th ed., (DSM-5). Washington, DC: American Psychiatric Publishing; 2013.