History and exam

Key diagnostic factors

common

presence of risk factors

Key risk factors include older age; recent childbirth, stress, or trauma; co-existing medical conditions (diabetes, cancer, stroke, myocardial infarction, and obesity); personal or family history of depression; certain medications (e.g., corticosteroids) and female sex.

depressed mood

Major criterion for diagnosis: depressed mood or loss of interest, most of the day, nearly every day, for a period of 2 weeks along with 4 other symptoms of depression.[1]

anhedonia

Major criterion for diagnosis: diminished interest or pleasure in all or almost all activities most of the day, nearly every day, for a period of 2 weeks along with 4 other symptoms of depression.[1]

functional impairment

Symptoms cause impairment in, for example, social or occupational functions.[1]

Other diagnostic factors

common

weight change

Significant weight loss when not dieting, weight gain, or decrease or increase in appetite nearly every day.[1] A change of >5% of body weight within 1 month is considered significant.[1]

libido changes

May show reduced libido.

sleep disturbance

Insomnia or hypersomnia persistently.[1]

changes in movement

Psychomotor agitation or retardation nearly every day.[1] The changes in movement should be observable by others, rather than subjective feelings of restlessness or being slowed down.[1]

low energy

Fatigue or loss of energy nearly every day.[1]

excessive guilt

Feelings of worthlessness or excessive or inappropriate guilt nearly every day.[1]

poor concentration

Diminished ability to think or concentrate, or indecisiveness, nearly every day.[1]

suicidal ideation

Recurrent thoughts of death, recurrent suicidal ideation without a specific plan, a specific suicide plan, or a suicide attempt.[1]

somatic symptoms

Somatic symptoms (e.g., headaches, generalised aches and pains, palpitations, tremor, blurred vision), although not comprehensively described in established diagnostic criteria, are commonly reported symptoms of depression, particularly in certain geographical populations, for example, people from Africa, Asia, Central and South America, and the Pacific Island, but may occur in people with depression regardless of their location or culture.[8][9]

bipolar disorder excluded

According to DSM-5-TR, there should be no evidence of mania or hypomania.[1]

substance abuse/medication side effects excluded

According to DSM-5-TR, major depressive disorder should not be diagnosed if the symptoms are primarily attributable to the pharmacological effects or side effects of prescribed medications or substances of abuse.[1]

medical illness excluded

According to DSM-5-TR, major depressive disorder should not be diagnosed if the symptoms are primarily attributable to a somatic medical condition.[1]

uncommon

schizophrenia excluded

According to DSM-5-TR, chronic psychosis excludes the diagnosis of major depressive disorder if the depressive symptoms are primarily attributable to the chronic psychotic illness.[1]

Risk factors

strong

postnatal status

Approximately 19% of postnatal women have a major depressive episode during the first 3 months after delivery.[83] Women with a previous psychiatric disturbance, poor social support, and an unplanned pregnancy are at higher risk.[12] Parenting programmes may improve the short-term psychosocial health of mothers.[84]​ See Postnatal depression.

personal or family history of depressive disorder or suicide

A family history of depression is associated with a twofold increased risk, more functional impairment, longer episodes, more frequent recurrence, and persistent thoughts of death and suicide.[85] The rate of suicide is twice as high in families of suicide victims.[86]

history of an anxiety disorder, or anxiety symptoms

Anxiety and depressive disorders are highly comorbid; according to one worldwide survey, 45.7% of people with major depressive disorder had a history of one or more anxiety disorders. Comorbidity with an anxiety disorder during depressive episodes was also common, occurring in 41.6% of people with depression.[87]​ According to the Sequenced Treatment Alternatives to Relieve Depression (STAR*D) study, 53% of the patients with major depression also had significant symptoms of anxiety (often termed 'anxious depression').[88]

adverse childhood experiences

Adversity or maltreatment during critical periods in early life has been demonstrated to substantially increase the risk of later development of depression, and is also associated with a less favourable course of illness, including an increased risk of recurrent depression; however, some studies suggest that antidepressant treatment can nevertheless be helpful in this population.[58][59]​​[89] The risk is not entirely psychological: it has been postulated that exposure to adverse events in early life may lead to epigenetic modifications affecting gene expression, which may predispose to depression.[57]​ Childhood adversity is also associated with increased risk of depression in people who have particular alleles of the polymorphic FKBP5 gene, which encodes a protein involved in glucocorticoid signaling pathways.[56]

dementia

In older adults with dementia, the prevalence of comorbid depression appears to be around 16%, although may be as high as 35% depending on the diagnostic criteria used; dementia, by some measures, can nearly double the risk of depression in older adults.[41]​ Depression may be a prodromal feature of dementia, or a psychological response to experiencing a degenerative disease with associated loss of function and autonomy.[90]​ Conversely, depression may also be a risk factor for dementia.[91]

corticosteroid use

Depression is a documented adverse effect.[92]

interferon use

Depression is a documented adverse effect and is treatable.[93]

oral contraceptive use

A large population-based study found a slight, but statistically significant elevated risk of depression in oral contraceptive users.[94]​ Risk appears to vary by age and hormone contents of the specific oral contraceptive.[95]

co-existing medical conditions

Patients hospitalised for medical or surgical problems and those with various chronic medical conditions, including diabetes, cancer, stroke, coronary artery disease, HIV, chronic pain, polycystic ovary syndrome, and obesity have significantly higher rates of depression than people without comorbidities.[13][14][15][16][96][97][98][99][100][101] There may be a particularly increased risk of depression in chronic illness in patients with conditions characterised by inflammation and pain.[102] The relationship between chronic medical conditions and depression is bidirectional. Depressed patients are more likely to develop chronic medical conditions.[43][44] Adults who experienced chronic medical illness in childhood also have higher rates of depression.[103]

female sex

Incidence of depression in women is double the incidence in men.​[27][33]

weak

comorbid substance use

The use of intoxicating substances (alcohol, cannabis, and other recreational drugs), often to an excessive or habitual degree, is common in people with depression.[38][104][105]​​ Men with depression are twice as likely as women to have a comorbid substance use disorder.[38] There is no evidence that medical cannabinoids are effective for the treatment of depression.[106] 

personality disorders

Some personality disorders co-occur more frequently with depression, including borderline personality disorder, and Cluster C personality disorders.[107][108][109] Depression combined with a personality disorder may have a poorer outcome than depression alone; however, data are mixed.[110]

history of violent victimisation

Having been the victim or witness of violence, such as physical or sexual abuse including intimate partner violence, is a risk factor for subsequent development of depression.[26][111]

obesity

New data analytic methods applied to several very large databases have supported the hypothesis that body fat mass is associated with, and likely a causal factor for, depression.[112] One population-based study conducted in Europe reported a significantly higher prevalence of depression in people with BMI >30 kg/m² compared with people with BMI >18.5 kg/m² and <30 kg/m².[27]

older age (≥65 years)

Rates of depression increase in older-age, particularly among older people who are hospitalised or living in assisted care facilities.[31]​ Global prevalence in elderly people has been estimated at 13.3%.[30]​ Another systematic review looking at rates of depression in older adults globally, estimated the pooled prevalence of depression as being 31.74%, with higher rates of depression seen within developing countries (40.78%) compared to developed countries (17.05%).[31]

separated/divorced marital status

Associated with an increased risk of developing major depressive disorder according to one systematic review.[26]

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