When viewing this topic in a different language, you may notice some differences in the way the content is structured, but it still reflects the latest evidence-based guidance.

Depression in adults

Last reviewed: 30 Oct 2023
Last updated: 13 Jun 2023



History and exam

Key diagnostic factors

  • depressed mood
  • anhedonia
  • functional impairment
More key diagnostic factors

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
Other diagnostic factors

Risk factors

  • postpartum status
  • personal or family history of depressive disorder or suicide
  • dementia
  • corticosteroids
  • interferon
  • propranolol
  • oral contraceptives
  • coexisting medical conditions
  • female sex
  • comorbid substance use
  • personality disorders
  • stressful life events
  • obesity
More risk factors

Diagnostic investigations

1st investigations to order

  • clinical diagnosis
  • metabolic panel
  • CBC
  • 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
More 1st investigations to order

Investigations to consider

  • 24-hour free cortisol
  • vitamin B12
  • folic acid
More investigations to consider

Treatment algorithm


severe depression, nonpregnant: psychotic, suicidal, severe psychomotor retardation impeding activities of daily living, catatonia, or severe agitation

moderate depression, nonpregnant: severe symptoms, significant impairment but no psychotic symptoms, no suicidal ideation, and no severe psychomotor retardation or agitation

mild depression, nonpregnant: low to moderate severity symptoms, partial impairment, no psychotic symptoms, no suicidal ideation, and no psychomotor retardation or agitation

treatment-resistant/refractory depression



treatment responsive

recurrent episode



Dean F. MacKinnon, MD

Associate Professor

Psychiatry and Behavioral Sciences

The Johns Hopkins Hospital




DFM declares that he has no competing interests.


Dr Dean F. MacKinnon would like to gratefully acknowledge Dr Roger S. McIntyre, Dr Tonya Fancher, and Dr Richard Kravitz, the previous contributors to this topic.


RSM has received research funds from Stanley Medical Research Institute and National Alliance for Research on Schizophrenia and Depression (NARSAD). RSM is on the advisory board for AstraZeneca, Bristol-Myers Squibb, France Foundation, GlaxoSmithKline, Janssen-Ortho, Solvay/Wyeth, Eli Lilly, Organon, Lundbeck, Biovail, Pfizer, Shire, and Schering-Plough. RSM is on the Speakers Bureau for Janssen-Ortho, AstraZeneca, Eli Lilly, Lundbeck, Biovail, and Wyeth. RSM has received research grants from Eli Lilly, Janssen-Ortho, Shire, and AstraZeneca. RSM has received travel funds from Bristol-Myers Squibb. TF declares that she has no competing interests. RK has received research grants from Pfizer on non-depression-related topics.

Peer reviewers

Scott McAfee, MD


Residency Training

St Vincent's Hospital




SM declares that he has no competing interests.

Dietmar Winkler, MD

Department of Psychiatry and Psychotherapy

Medical University of Vienna




DW has received lecture fees from CSC Pharmaceuticals, GlaxoSmithKline, and Pfizer, and has served as a consultant for GlaxoSmithKline.

  • Differentials

    • Adjustment disorder with depressed mood
    • Substance-/medication- or medical illness-associated and other depressive disorders
    • Bipolar disorder
    More Differentials
  • Guidelines

    • Nonpharmacologic and pharmacologic treatment of adults in the acute phase of major depressive disorder
    • VA/DoD clinical practice guideline for the management of major depressive disorder
    More Guidelines
  • Patient leaflets

    Depression in adults: what is it?

    Depression in adults: what treatments work?

    More Patient leaflets
  • Calculators

    Geriatric Depression Scale

    Depression (any) Screening by a Two Item PHQ-2

    More Calculators
  • padlock-lockedLog in or subscribe to access all of BMJ Best Practice

Use of this content is subject to our disclaimer