Depression

Depression typically begins in adulthood; however, it can occur in children or adolescents typically with a more noticeable irritability than the low mood which is more commonly observed in adults (NIMH, 2022).

Adults who develop a chronic mood or anxiety disorder may have experienced high levels of anxiety as a child (NIMH, 2022).

Risk Factors

Risk factors include:

  • Personal or family history of depression

  • Major life changes, trauma, or stress

  • Certain physical illnesses and medications

DSM-Classified Depressive Disorders

There are 8 depressive disorders of which major depressive disorder is one.

Adapted from APA, 2013.

Video: Major Depressive Disorder

5:38

The DSM5 classifies depressive disorders as characterized by persistent feelings of sadness and worthlessness and a lack of desire to engage in formerly pleasurable activities. In this video, we will learn about the nine common symptoms of major depressive disorder and a brief overview of the mechanisms of action.

Question

What are the nine common symptoms of major depressive disorder?

The individual must be experiencing five or more symptoms during the same 2-week period and at least one of the symptoms should be either (1) depressed mood or (2) loss of interest or pleasure.

  • Depressed mood most of the day, nearly every day

  • Markedly diminished interest or pleasure in all, or almost all, activities most of the day, nearly every day (anhedonia)

  • Significant weight loss when not dieting or weight gain or a decrease or increase in appetite nearly every day

  • Sleep disturbance

  • Fatigue or loss of energy nearly every day

  • A slowing down of thought and a reduction of physical movement (observable by others, not merely subjective feelings of restlessness or being slowed down)

  • Feelings of worthlessness or excessive or inappropriate guilt nearly every day

  • Diminished ability to think or concentrate, or indecisiveness, nearly every day

  • Recurrent thoughts of death, recurrent suicidal ideation without a specific plan, or a suicide attempt or a specific plan for committing suicide (APA, 2013)

To receive a diagnosis of depression, these symptoms must cause the individual clinically significant distress or impairment in social, occupational, or other important areas of functioning. The symptoms must also not be a result of substance abuse or another medical condition (APA, 2013).

Screening and Monitoring Instruments

The PHQ-2 and PHQ-9 are the most commonly used screening and monitoring instruments for depression in clinical practice, demonstrating utility and diagnostic accuracy (Siniscalchi et al., 2020). For both the PHQ-2 and PHQ-9, scores of 0 (“not at all”) to 3 (“nearly every day”) are used for diagnosis.

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PHQ-2

The PHQ-2 asks two questions about the frequency of depressed mood and anhedonia of which a person with major depressive disorder must experience one. An overall PHQ-2 score of ≥3 (out of a possible 6) is 92% effective for detecting major depression disorder (Kroenke et al., 2003; Fuchs et al., 2015).

PHQ-9

The PHQ-9 asks nine questions based on the nine criteria for major depressive disorder in the DSM-5. At Numinus, the PHQ-9 is used as a screening and monitoring instrument for depressive symptoms, administered at intake, and following Medicine Sessions.

In the PHQ-9, scores are classified as follows with the highest score possible being 27.

PHQ-9 Score Diagnosis
5 Mild depression
10 Moderate depression
15 Moderately severe depression
20 Severe depression

Learn More

For an example of a matrix used by Alberta Health Services to screen clients for major depressive disorder, please download their patient health questionnaire.

Treatment

There are several treatment approaches for depression including medication, electroconvulsive therapy, and ketamine treatment. As discussed in the Molecular Foundations course, ketamine can be used at moderately high doses for ketamine-assisted therapy or ketamine can be used as a standalone treatment without psychotherapy.

Other evidence-based psychotherapy treatments for depression include cognitive behavioural therapy, mindfulness-based cognitive therapy, acceptance and commitment therapy, and interpersonal (SAMSHA, 2016; Markowitz, 2004; MacKenzie, 2016).

References

American Psychiatric Association (2013). Diagnostic and statistical manual of mental disorders (5th ed.).

Fuchs, C. H., Haradhvala, N., Hubley, S., Nash, J. M., Keller, M. B., Ashley, D., Weisberg, R. B., & Uebelacker, L. A. (2015). Physician actions following a positive PHQ-2: implications for the implementation of depression screening in family medicine practice. Families, systems & health : the journal of collaborative family healthcare, 33(1), 18–27.

Kroenke, K., Spitzer, R. L., & Williams, J. B. (2003). The Patient Health Questionnaire-2: validity of a two-item depression screener. Medical care, 41(11), 1284–1292.

MacKenzie, M. B., & Kocovski, N. L. (2016). Mindfulness-based cognitive therapy for depression: trends and developments. Psychology research and behavior management, 9, 125–132.

Markowitz, J. C., & Weissman, M. M. (2004). Interpersonal psychotherapy: principles and applications. World psychiatry: official journal of the World Psychiatric Association (WPA), 3(3), 136–139.

National Institute of Mental Health (2022). Depression.

SAMHSA. (2016). VA/DOD Clinical Practice Guideline for the Management of Major Depressive Disorder. Department of Veterans Affairs & Department of Defense.

Siniscalchi, K. A., Broome, M. E., Fish, J., Ventimiglia, J., Thompson, J., Roy, P., Pipes, R., & Trivedi, M. (2020). Depression Screening and Measurement-Based Care in Primary Care. Journal of primary care & community health, 11, 2150132720931261.