Diagnosis and Symptoms

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Diagnosis and Symptoms of MDD

The majority of patients with MDD present to their family doctor and are diagnosed in primary care. However, depression is generally underdetected and underdiagnosed in this setting. Older adults rarely see mental health specialists, and are therefore at a higher risk of missed diagnosis.[1] Early diagnosis helps ensure early access to treatment, which is important to help improve quality of life.[2]

Symptoms of MDD

The symptoms of MDD can be severe and prevail even after an acute episode.[3]

Typical signs and symptoms of MDD can be clustered into three key domains:[4][5]


Such as persistent low mood, anhedonia, feelings of worthlessness, hopelessness, guilt, or suicide[5]


Including impaired attention, memory, executive function[4]


For example sleep disturbance, sexual dysfunction, reduced appetite[5]

Symptoms of the MDD subtypes

Please refer back to 'Subtypes of major depression' in the 'About Major Depressive Disorder' section

More detailed information is available on the 'About MDD' page.

Diagnosing MDD

An MDD diagnosis is made by a combination of the patient’s detailed clinical history and psychiatric evaluation.[6]

This includes:

Medical, social and family history

e.g. first-degree relative with depression, a history of child abuse, marital status

History of substance use
Symptoms of MDD

(with relevant input from carers, family and friends)

A comprehensive physical examination

To rule out any underlying medical cause / to identify any contributing factors

Mental health status assessment

Includes using a validated depression diagnostic test such as a rating scale

Rating scales used to diagnose / assess depression

Given the heterogeneity in signs and symptoms of depression, it is not surprising that a range of different rating scales have been developed.
Rating scales are useful for screening and assessment and also, if used regularly, to monitor the effectiveness of treatment in order to support therapeutic decision making.

The most commonly used rating scales are described below:

Hamilton Rating Scale (HAMD-17)
A 17-item physician-administered scale that measures severity of depression on a scale of 0–2 or 0–4, with higher scores (≥ 24) indicating severe depression

A number of modified (short) versions have been published – a literature review published in 2020 determined that structured versions deliver the highest inter-rater and test-retest reliability[7]
Montgomery-Åsberg Depression Rating Scale (MADRS)

A 10-item physician-administered scale that rates depressive symptoms on a scale of 0–6, giving a maximum score of 60[8]

Beck Depression Inventory (BDI)

A 21-item patient-reported measure of depression severity that rates symptoms on a 0–3 scale, with higher scores (above 10) indicating increased severity[9]

Patient Health Questionnaire-9 (PHQ-9)

A 9-item patient-reported rating scale designed as a screening tool for use in primary care

The standard cut-off score for screening to identify possible major depression is 10 or above[10]

Edinburgh Postnatal Depression Scale (EPDS)

A 10-item patient-reported rating scale used to screen for postpartum / antepartum depression with a maximum score of 30

Cut-off values of 10 or 13 are most commonly used[11][12][13][14]

Clinical Global Impressions Scale (CGI)

Two single-item companion measures assessing severity (CGI-S) and improvement (CGI-I) on a 7-point scale. It is designed to be completed in less than a minute by an experienced rater, taking into account all available case details including a patient's history, psychosocial circumstances, symptoms, behavior and ability to function[15]
Zung Self-Rating Depression Scale (SDS)
A 20-item patient-reported rating scale to screen for the presence of depressive disorders in adults. The SDS is widely used, particularly in the research context, with suggested cut-off index values between 50 to 55 depending on population[16][17]

MDD is classified using DSM-5 or ICD-10[5][18]

Major depression (major depressive disorder, MDD) classification is based on either the 2013 Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) or the International Classification of Diseases, 10th Revision (ICD-10) classification of mental and behavioural disorders.[5][18] An update to the ICD has been developed (ICD-11), but global uptake and implementation is still underway.[19]

At least five of the following symptoms causing clinically significant distress or impairment over a 2-week period (including No. 1 or 2):

1. Depressed mood most of the day, nearly every day, either self-reported (e.g., feels sad, empty, hopeless) or observed by others (e.g., appears tearful)

2. Markedly diminished interest or pleasure in all, or almost all, activities most of the day, nearly every day

3. Significant weight changes (e.g., ±5% body weight over a month) or change in appetite nearly every day

4. Insomnia or hypersomnia nearly every day

5. Psychomotor agitation or retardation nearly every day

6. Fatigue or loss of energy nearly every day

7. Feelings of worthlessness or excessive or inappropriate guilt nearly every day

8. Diminished ability to think or concentrate, or indecisiveness, nearly every day

9. Recurrent thoughts of death or suicidal ideation, or a suicide attempt

The full DSM-5 diagnostic criteria can be found here: (https://dsm.psychiatryonline.org)

ICD-10 classification / specifiers for MDD (Version: 2019)[18]

ICD-10 classifies depression according to severity and length of time of symptoms.

Depressive episode

Low mood, low energy, decrease in activity. Capacity for enjoyment, interest, and concentration is reduced, and marked tiredness after even minimum effort is common. Sleep is usually disturbed and appetite diminished. Self-esteem and self-confidence are almost always reduced and feelings of guilt or worthlessness are often present. Low mood varies little from day to day, is unresponsive to circumstances and may be accompanied by somatic symptoms, such as loss of interest and pleasurable feelings, waking in the morning several hours before the usual time, depression worst in the morning, marked psychomotor retardation, agitation, loss of appetite, weight loss, and loss of libido. Depending upon the number and severity of the symptoms, a depressive episode may be specified as mild, moderate or severe.

Mild depressive episode

An episode of depression in which two or three symptoms are present, and the patient is distressed, but will function relatively normally

Moderate depressive episode

An episode of depression in which four or more symptoms are present, and function is impaired

Severe depressive episode without psychotic symptoms

An episode of depression in which several of the above symptoms are marked and distressing, typically loss of self-esteem and ideas of worthlessness or guilt. Suicidal thoughts and acts are common and a number of somatic symptoms are usually present

Severe depressive episode with psychotic symptoms

An episode of depression as previously described, but with hallucinations, delusions, psychomotor retardation, or stupor so severe that ordinary social activities are impossible

To learn more about the causes of major depression, visit the ‘Causes of MDD' page


BDI, Beck Depression Inventory. CGI, Clinical Global Impressions Scale. DSM-5, Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition. EPDS, Edinburgh Postnatal Depression Scale. HAMD-17, Hamilton Depression Rating Scale. MADRS, Montgomery and Asberg Depression Rating Scale. MDD, Major depressive disorder. PHQ-9, Patient Health Questionnaire-9. SAD, Seasonal affective disorder. SDS, Zung Self-Rating Depression Scale.