Major Depressive Disorder in Adults - Diagnosis and Management

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Effective Date: December 15, 2013

Recommendations and Topics


This guideline provides recommendations on how to diagnose and manage major depressive disorder (MDD) in the primary care setting for non-pregnant patients aged 19 – 65 years. It does not include recommendations for MDD subtypes (e.g., postpartum depression, seasonal affective disorder, psychotic depression, atypical depression and melancholic depression), other depressive disorders (e.g., disruptive mood dysregulation disorder, persistent depressive disorder (dysthmymia), premenstrual dysphoric disorder, treatment resistant/induced depression), psychosis, bipolar disorder, anxiety disorders, or substance abuse disorders.


Key Recommendations

  • Screen for MDD with 'two quick question' method.
  • Use the Patient Health Questionnaire-9 (PHQ-9) to aid in diagnosing and monitoring patients.
  • Assess suicide risk in all depressed patients.
  • Several non-pharmacological and pharmacological interventions are available in the short, medium and long term.
  • Antidepressants are continued for at least 6 months after remission.
  • Treat to recover occupational and social functioning.



Approximately 11% of Canadians meet criteria for MDD at some point in their lives and approximately 4% of Canadians suffer from MDD within any given year.1 About 2% of people with depression commit suicide, and 50% of these individuals will have been in contact with their general practitioner in the month preceding the suicide.2




Screen patients who present with symptoms for MDD.3 Note that some patients present with somatic symptoms. Use the 'two quick question' screening method.4

In the past month:

  • Have you lost interest or pleasure in things you usually like to do?
  • Have you felt sad, low, down, depressed or hopeless?

An answer of yes to either question requires a more detailed assessment.


The detailed assessment includes:

  • Clinical interview to determine if the patient meets the Diagnostic and Statistical Manual of Mental Disorders (5th edition)5 criteria to diagnose MDD by using S2IGECAPS and focusing on functional status.


Sadness (depressed mood)


Sleep disturbance (insomnia, hypersomnia)


Interest reduced (anhedonia)


Guilt and self-blame


Energy loss and fatigue


Concentration problems


Appetite changes (low/increased appetite or weight loss/gain)


Psychomotor changes (retardation, agitation)


Suicidal thoughts

  • Review PHQ-9 score and responses.* The PHQ-9 is a patient administered questionnaire that aids in the diagnosis and assesses the severity (e.g., mild, moderate, severe) of depression.6-9
  • Consider:
  • Differential diagnosis, particularly screening for Bipolar I and II;
  • Past history of depression and its treatment;
  • Family history of a mood disorder;
  • Psychosocial stressors;
  • Any medical conditions associated with depression (e.g., chronic obstructive pulmonary disease, migraine, multiple sclerosis, back problems, cancer, epilepsy, asthma, stroke, thyroid disease, diabetes and heart disease);10 and
  • Collateral information from family or friends.10

Differential Diagnosis

When arriving at the differential diagnosis, consider the following:

  • Ruling out medical conditions that require laboratory tests (e.g., thyroid stimulating hormone, Vitamin B12);11
  • Other psychiatric syndrome (e.g., adjustment disorder, anxiety disorder, bipolar disorder I or II, psychosis, alcohol and/or substance abuse);12 and
  • Medications that mimic mood disorders (see Appendix A: Medications that Mimic Mood Disorders [PDF, 100KB]).

Suicide Risk Assessment 

Once patient has met MDD criteria, conduct a suicide risk assessment.12-14

  • Ask the patient if they have thoughts of death or suicide, feel life is not worth living, have made a previous suicide attempt and if there is a family history of suicide.
  • If the answer is yes to any of the above, ask about their plans for suicide (e.g., have they considered a method, do they have access to material required for suicide and if they have written a note).
  • Consider emergency psychiatric consultation and in-patient treatment if the patient has: persistent suicidal thoughts; a previous suicide attempt; or a current plan.
  • If the patient is considered low risk, discuss and/or create a safety plan with the patient, detailing steps the patient will take if their situation deteriorates15 (see Associated Document: Example of a Safety Plan).

Depression should not be diagnosed or excluded solely on the basis of a PHQ-9 score. See Associated Document: Patient Health Questionnaire – 9 for more information (PDF, 41KB).

† Generalized anxiety or worry can accompany depression symptoms. This should not be diagnosed separately if the excessive worry presents only during the major depressive event.5

‡ For more information on conducting a suicide risk assessment see the Associated Document: Resource Guide: Information Sources for Physicians (PDF, 145KB).




The goal of acute treatment is remission of symptoms (e.g., PHQ-9 score < 5) and to restore psychosocial functioning. The goal of maintenance treatment is to return to full social and occupational function and to prevent recurrence.

  • Establish treatment decisions on the severity of the depression, patient preference and availability of resources.
  • Use the clinical interview and PHQ-9 score help to assess severity of depression and to evaluate treatment response.
  • Assess suicide risk at each visit, especially in the acute phase.16
  • Treatment of depression can also be impacted by stressors in interpersonal relationships, living conditions and social isolation. These stressors should also be assessed and managed.
  • Initially follow up with patients weekly or biweekly, depending on severity, until acute treatment goals are met. Schedule periodic visits to ensure maintenance treatment goals are met.

Best results for treatment adherence occur when a therapeutic alliance has been formed between the physician and patient.17,18 Involve patients in the management of their own illness by engaging them in discussion about the diagnosis and treatment options, developing a goal-oriented treatment plan§, and monitoring for response and signs of relapse/recurrence (see Associated Document: Resource Guide: Information Sources for Patients [PDF, 140KB]).

§ GPSC incentive fee may be available for mental health planning.

1. Lifestyle – Self-Care19

Recommend lifestyle management for all patients with depression. Discuss the importance of a healthy lifestyle such as:

  • Regular exercise
  • Healthy regular meals
  • Sleep hygiene
  • Avoiding substance use
  • Adequate housing
  • Stress management strategies
  • Engaging in at least one pleasurable activity a day
  • Keeping a daily mood chart

2. Self-Management20

Recommend self-management for all patients with depression. When appropriate, use education and self-management resources (see Associated Document: Resource Guide: Information Sources for Physicians [PDF, 145KB]), including available community resources and self-help agencies. Self-management programs may be helpful to prevent relapses.

3. Psychotherapy

Recommend psychotherapy in the acute phase of mild to moderate depression and/or maintenance phase of depression treatment to prevent relapse. First-line psychotherapies are cognitive behavioral therapy and interpersonal psychotherapy (see Appendix B: First-Line Psychotherapies for Treatment of Depression [PDF, 99KB]).

Psychotherapies are as effective as antidepressant medications, and for some patients, combined treatment with pharmacotherapy and psychotherapy is more effective than psychotherapy alone.21 Combined treatment should be considered for patients with chronic or severe episodes, psychiatric co-morbidity, or poor response to pharmacotherapy.

Patients referred for psychotherapy or engaging in self-management programs should also be monitored for treatment response at monthly or bimonthly intervals. Inter-professional communication is extremely important when treating shared patients.

4. Pharmacological Management

Recommend antidepressant medications for patients with moderate to severe depression.

Many first-line antidepressants are available with different neurochemical actions and side effect profiles (see Appendix C: First-Line Antidepressants [PDF, 138KB]). Most systematic reviews have not shown any clinically significant differences in efficacy among first-line antidepressants;22 however, consider the following clinical factors when choosing a medication for patients.23

  • Symptom profile
  • Medical co-morbidity
  • Psychiatric co-morbidity
  • Risk of pregnancy
  • Patient preference
  • Previous therapeutic response
  • Tolerability profile
  • Drug discontinuation symptoms
  • Drug-drug interactions
  • Cost

Initially, patients are typically prescribed a first-line antidepressant (see Appendix C: First-Line Antidepressants [PDF, 138KB] for more information). If there is no response to an adequate trial (e.g., 2-4 weeks at the maximum dosage) of the first-line antidepressant or its side effects are intolerable, switch to another first line agent, which could include another agent in the same class (see Appendix D: Switching Antidepressants [PDF, 117KB]).

Antidepressant partial or poor response may be augmented with another agent; at this point psychiatric consultation is recommended. Consider reviewing drug and alcohol use again.

Engage the patient in an open dialogue about side effects when prescribing antidepressants. Specifically discuss the potential increase in suicidal ideation and potential for sexual dysfunction. Agitation and suicide risk may increase early in pharmacological treatment. Patients should be carefully monitored at least every 1-2 weeks when starting drug therapy.24 Ask the patient to review the safety plan (see Associated Document: Example of a Safety Plan [PDF, 16KB]) and seek out emergency help if symptoms become more prominent and suicidal thoughts become more persistent. Treatment-related sexual dysfunction usually persists, and if intolerable, changing therapy may be warranted.24

Promote antidepressant adherence, by addressing any medication concerns of the patient and by providing them with the following information.24

  • Antidepressants are not addictive.
  • Do not stop antidepressants without medical consultation, even if feeling better, to avoid withdrawal symptoms.
  • Take antidepressants as directed.
  • Some improvement may be observed as early as the first 1-2 weeks, but full benefit may not be observed until 4-8 weeks.
  • Mild side effects (e.g., gastrointestinal, headaches) are common but transient; however, persistent symptoms should be reported.

Maintenance Treatment

Continue patients on antidepressants for at least 6 months after full remission of symptoms or achievement of treatment goals.25 Use the same dosage as in the acute phase. Monitor for medication side effects and medical co-morbidity.

When ending pharmacological treatment, the following are recommended.

Other Management

Consultation with a psychiatrist is recommended for:

  • Bipolar disorder, psychotic symptoms and/or a substance use disorder;
  • Risk of suicide or harm to others;
  • Severe co-morbid psychiatric or medical illness;
  • History of treatment resistance;
  • Failed to respond to standard treatment (at adequate dosage and time-period);
  • An unclear diagnosis that needs a more comprehensive evaluation; and
  • Therapeutic relationship has broken down.




  1. Minister of Public Works and Government Services Canada. The human face of mental health and mental illness in Canada [Internet]. Ottawa: Government of Canada; 2006 [cited 2013 Jun 25].
  2. Luoma JB, Martin CE, Pearson JL. Contact with mental health and primary care providers before suicide: a review of the evidence. Am J Psychiatry. 2002;159(6):909-16.
  3. Canadian Task Force on Preventative Health Care. Recommendations on screening for depression in adults. CMAJ. 2013;185(9):775-82.
  4. Whooley MA, Avins AL, Miranda J, et al. Case-finding instruments for depression: two questions are as good as many. J Gen Intern Med. 1997;12(7):439-445.
  5. American Psychiatric Association. Diagnostic and statistical manual of mental disorders, Fifth Edition. Washington, DC: American Psychiatric Association; 2013.
  6. Kroenke K, Spitzer RL, Williams JBW. The PHQ-9: Validity of a brief depression severity measure. J Gen Intern Med. 2001 Sep;16:606-13.
  7. Kroenke K, Spitzer RL. The PHQ-9: A new depression diagnostic and severity measure. Psychiatr Ann. 2002;32(9):509-15.
  8. Gelenberg AJ. Using assessment tools to screen for, diagnose, and treat major depressive disorder in clinical practice. J Clin Psychiatry. 2010;71(Suppl E1):1-13.
  9. Patten SB, Schopflocher D. Longitudinal epidemiology of major depression as assessed by the brief Patient Health Questionnaire (PHQ-9). Compr Psychiatry. 2009;50(1):26-33.
  10. Patten SB, Kennedy SH, Lam RW, et al. Canadian Network for Mood and Anxiety Treatments (CANMAT) clinical guidelines for the management of major depressive disorder in adults. I. Classification, burden and principles of management. J Affect Disord. 2009;117:S5-S14.
  11. Nutt DJ, Davidson JRT, Gelenberg AJ, et al. International consensus statement on major depressive disorder. J Clin Psychiatry. 2010;71(suppl EI):1-14.
  12. Lake CR, Baumer J. Academic psychiatry’s responsibility for increasing the recognition of mood disorders and risk for suicide in primary care. Curr Opin Psychiatry. 2010;23:157-66.
  13. Bilsker D. Samra J. Working with the suicidal patient: A guide for health care professionals [Internet]. Vancouver: Consortium for Organizational Mental Health; 2007 [cited 2013 Jul 19].
  14. Rubenstein L, Unutzer J, Miranda J, et al. Partners in Care: Clinician Guide to Depression Assessment and Management in Primary Care. (Volume 1) RAND, Santa Monica, 1996.
  15. Samra J, Bilsker D. Coping with Suicidal Thoughts [Internet]. Vancouver: Consortium for Organizational Mental Health; 2007 [cited 2013 Jun 21].
  16. Bauer M, Bschor T, Pfennig A, et al. WFSBP task force on unipolar depressive disorders. World federation of societies of biological psychiatry (WFSBP) guidelines for biological treatment of unipolar depressive disorders in primary care. World J Biol Psychiatry. 2007;8(2):67-104.
  17. Krupnick JL, Sotsky SM, Simmens S, et al. The role of the therapeutic alliance in psychotherapy and pharmacotherapy outcome: Findings in the national institute of mental health treatment of depression collaborative research program. J Consult Clin Psychol. 1996;64(3):532-39.
  18. Byrne N, Regan C, Livingston G. Adherence to treatment in mood disorders. Curr Opin Psychiatry. 2006;19(1):44-9.
  19. Canadian Mental Health Association [Internet]. Ottawa (ON): Canadian Mental Health Association; c2013. Benefits of good mental health; 2013 [cited July 25, 2013].
  20. Bilsker D, Goldner EM, Anderson E. Supported self-management: A simple, effective way to improve depression care. Can J Psychiatry. 2012;57(4):203-09.
  21. De Jonghe F, Kool S, van Aalst G, et al. Combining psychotherapy and antidepressants in the treatment of depression. J Affect Disord. 2001;64:217-29.
  22. Cipriani A, Bargbui C, Butler R, et al. Depression in adults: drug and physical treatments. Clinical Evidence. 2011;05:1-40.
  23. Dupuy JM, Ostacher MJ, Huffman J,et al. A critical review of pharmacotherapy for major depressive disorder. Int J Neuropsychopharmacol. 2011;14:1417-31.
  24. Lam RW, Kennedy SH, Grigoriadis S, et al. Canadian network for mood and anxiety treatments (CANMAT) clinical guidelines for the management of major depressive disorder in adults. III. Psychotherapy. J Affect Disord. 2009;117:S26-S43.
  25. Piek E, van der Meer K, Nolen WA. Guideline recommendations for long-term treatment of depression with antidepressants in primary care – a critical review. Eur J Gen Pract. 2010;16:106-12.

Diagnostic Code: 311


Associated Documents

The following documents accompany this guideline:


This guideline is based on scientific evidence current as of the Effective Date.

This guideline was developed by the Guidelines and Protocols Advisory Committee, approved by the British Columbia Medical Association, and adopted by the Medical Services Commission.

The principles of the Guidelines and Protocols Advisory Committee are to:

  • encourage appropriate responses to common medical situations
  • recommend actions that are sufficient and efficient, neither excessive nor deficient
  • permit exceptions when justified by clinical circumstances.
Contact Information
Guidelines and Protocols Advisory Committee
Victoria BC V8W 9P1
Web site:
Clinical Practice Guidelines


Disclaimer The Clinical Practice Guidelines (the "Guidelines") have been developed by the Guidelines and Protocols Advisory Committee on behalf of the Medical Services Commission. The Guidelines are intended to give an understanding of a clinical problem and outline one or more preferred approaches to the investigation and management of the problem. The Guidelines are not intended as a substitute for the advice or professional judgment of a health care professional, nor are they intended to be the only approach to the management of clinical problems.  We cannot respond to patients or patient advocates requesting advice on issues related to medical conditions. If you need medical advice, please contact a health care professional.