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This website is made possible by third party financial support from Sage Therapeutics, Inc. and Biogen Inc.

How Is Depression Diagnosed?

How Is Depression Diagnosed?

February 26, 2021

Learn how DSM-5 and ICD-10 clinical guidelines are used to help classify severity, duration, and subtype of depression.

doctor exam

There are different classification systems designed to diagnose depression. Both DSM-5 and ICD-10 criteria are commonly used by clinicians to help in diagnosis and treatment of depression. In fact, based on DSM-5 or ICD-10 criteria, two people can be diagnosed with depression but not share a single symptom. Both DSM-5 and ICD-10 classify depression by severity, duration, and subtypes, all of which can impact treatment decisions.

The DSM-5 lists the following criteria for the diagnosis of major depressive disorder (MDD)1:

  1. Five (or more) of the following symptoms are present for a 2-week duration and are a change from the previous functioning level. The criteria most occur nearly every day. At least 1 of the symptoms is either (a) depressed mood or (2) loss of interest or pleasure.
    • Depressed mood lasting most of the day. This includes subjective observation (reporting feeling sad, empty, and/or hopeless) or observations made by others around the individuals (such as increased tearfulness).
    • Markedly decreased interest or pleasure in all, or nearly all, activities lasting most of the day.
    • Significant weight loss or weight gain, not attributed to other sources such as dieting, or decrease in appetite. This is a weight change of more than 5% in body weight.
    • Insomnia or hypersomnia.
    • Psychomotor agitation or retardation that is observable by others around the individual (not just a feeling of being slowed down or agitated).
    • Fatigue or loss of energy.
    • Feelings of worthlessness or excessive or inappropriate guilt.
    • Diminished ability to think and concentrate, or indecisiveness.
    • Recurrent thoughts of death, suicidal ideation, or a suicide attempt.
  2. The symptoms cause clinical distress and impair the individuals social and occupational areas of functioning.
  3. The symptoms are not attributable to the use of substances or other medical conditions.
  4. These symptoms cannot be attributed to other disorders such as schizoaffective disorder, schizophrenia, schizophreniform disorder, delusional disorder, unspecified schizophrenia spectrum, or other psychotic disorders.
  5. The individual has never experienced a manic or hypomanic episode.

Criteria 1-3 make up the criteria for a major depressive episode.1

The most common symptoms patients experience when presenting for diagnosis are insomnia and fatigue.1 Psychomotor symptoms are much less common, but their presence indicates a greater overall severity of MDD.1 Healthcare providers should do a complete diagnostic evaluation including bloodwork prior to diagnosis. Medical conditions, such as thyroid problems or vitamin deficiencies, can cause depression-like symptoms.2

There are multiple associated features that can be used to support the diagnosis of MDD. Patients with MDD have a higher mortality rate, mostly attributed to suicide.1 Individuals with depression admitted to nursing homes are more likely to die within the first year than others not diagnosed with depression.1


  1. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders. 5th ed. American Psychiatric Association; 2013.
  2. What is depression? American Psychiatric Association. Updated October 2020. Accessed January 26, 2020.