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  • Writer's pictureDr. Gabrielle Schreyer-Hoffman

Depression: Symptoms, Course, Causes, and Treatment

Depression is a common mental health disorder that affects millions of people worldwide. It is characterized by a persistent feeling of sadness and loss of interest in activities that were once enjoyable. Depression can also cause changes in appetite, sleep, energy levels, concentration, and self-esteem.

Major Depressive Disorder (MDD) is one of the most common disorders worldwide. It is estimated that 21 million adults in the United States have had at least one major depressive episode in their lifetime (USDHHS, 2022). Depression can onset at any age, although the likelihood increases in and after puberty; in the United States incidences of depression peak around the mid-twenties (APA, 2000; APA, 2013). The onset of depression later in life is also not uncommon, especially when one is suffering from a chronic or severe medical condition (APA, 2000; APA, 2013; Meng & D’Arcy, 2014). Depression is more common in adolescent and adult females than in adolescent and adult males (USDHHS, 2022; APA, 2000; APA, 2013; Meng & D’Arcy, 2014).

Description of Depression Symptoms:

Depression is characterized as having one or more Major Depressive Episodes (APA, 2000; APA, 2013). One suffering from Depression may experience a lack of emotions (i.e., experiencing no feelings), feelings of anxiety, sadness, increased irritability over minor events, or somatizations (e.g., bodily pains or tensions and/or headaches) (APA, 2000; APA, 2013). Brooding and rumination are also not uncommon complaints of depressed patients (APA, 2013). There is usually a loss of interest or pleasure. For example, one may withdraw from activities that are important to them or that once brought them joy (e.g., hobbies and social activities), and “in some individuals, there is a significant reduction from previous levels of sexual interest or desire” (APA, 2013, p. 163). Many individuals become socially withdrawn or experience challenges in their social interactions when they’re depressed (APA, 2013).

One might also experience psychomotor agitation (i.e., difficulty sitting still or fidgeting) or psychomotor retardation (i.e., slowed down thinking, speech, movements, long pauses before answering) and/or decreased energy (e.g., fatigue with minimal or no physical exertion) (APA, 2000; APA, 2013). Patients also commonly report experiencing difficulties with concentration, memory, and decision-making (APA, 2013). In some cases, one is unable to engage in cognitively demanding tasks and as a result will see a drop in grades or poor work quality (APA, 2013). A potential explanation for these cognitive deficits during a depressive episode is that, when one is depressed, one tends to engage in-depression-relevant thinking (negative thinking or rumination), which takes up cognitive resources and energy available for performing other tasks (Hartlage, Alloy, Vazquez, & Dykman, 1993). Typically, one returns to their previous level of functioning after receiving treatment for the depression or when the episode passes and their depression goes into remission (APA, 2000; APA, 2013).

The symptoms of depression can vary from person to person, but they often include some of the following symptoms for most of the day nearly every day for 2 weeks or more:

  • Sadness

  • Feelings of Emptiness

  • Loss of interest or pleasure in activities

  • Changes in appetite or weight (either increased or decreased)

  • Insomnia or hypersomnia (either sleeping is increased or decreased)

  • Fatigue

  • Difficulty concentrating

  • Difficulty making decisions

  • Thoughts of death or suicide

  • Feelings of worthlessness or guilt

Course of depression:

The course of depression is variable. Some individuals rarely “experience remission (a period of 2 or more months with no symptoms, or only one or two symptoms to no more than a mild degree), while others experience many years with few or no symptoms between discrete episodes” (APA, 2013, p. 165). Recovery typically begins within 3 months to 1 year of the onset of MDD (APA, 2013). The risk of MDD recurrence is higher when the previous episode was severe, the individual is younger, mild depressive symptoms occurred in remission, and the patient has had multiple previous episodes (APA, 2013). The risk of recurrence reduces as the remission duration

increases (APA, 2013).

Causes of depression:

The causes of depression are variable and not fully understood as no one circumstance or cause predicts the onset of depression. It is widely held that a combination of genetic, environmental, and psychological factors creates the circumstances for depression. Some of the things that can increase your risk of developing depression include:

  • Family history of depression, especially a first-degree biological relative with depression

  • Temperament, especially high levels of neuroticism, place one at a higher risk for depressive episodes in reaction to stressful life events (APA, 2013)

  • Personal history of trauma or abuse

  • Exposure to adverse experiences in childhood (e.g., dysfunctional family environment, parental negativity or highly punitive parenting styles, or early experiences with trauma or childhood abuse)

  • Certain medical conditions, such as chronic pain or thyroid problems

  • Substance abuse

  • Smoking Cigarettes as cigarette smoke contains neurotoxins that may be involved in the mechanisms of depression (Quattrocki, Baird, & Yurgelun-Tood, 2000 as cited in Meng & D’Arcy, 2014)

  • Stressful life events (e.g., job loss, divorce, poor social support, or marital problems)

Treatment for depression:

There are many effective treatments for depression including therapy, psychotropic medication, and lifestyle changes. Cognitive Behavioral Therapy (CBT) has empirical support for treating depression (APA, 2010); Using techniques like “behavioral activation, problem-solving, cognitive restructuring, and homework…” patients are able to learn effective skills to better cope with their depression and see improvement in symptoms (Simons et al., 2010). CBT is also shown to have superior relapse prevention compared to other treatments of depression (Lopez & Basco, 2014). Additionally, it is shown that CBT with medication therapy can be more potent than CBT alone or medication alone (APA, 2010). Therapy can help you understand the causes of your depression and develop coping skills and tools. Lifestyle changes, such as getting regular exercise and movement, a healthful diet, and improved sleep hygiene, can also help to improve your overall well-being.

If you are struggling with depression, don’t wait seek professional help, find a therapist right away. There are many effective treatments available to help you navigate these challenges. You do not have to go through this alone.


1. U.S. Department of Health and Human Services (USDHHS). (2022). Major depression. National Institute of Mental Health.

2. American Psychiatric Association (APA). (2000). Diagnostic and statistical manual of mental disorders (4th ed., text rev.).

Washington, DC: Author.

3. American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). Washington, DC:


4. American Psychiatric Association. (2010). Practice guideline for the treatment of patients with major depressive disorder,

(3rd ed.). Retrieved from

5. Lopez, M., & Basco, M. (2014). Effectiveness of cognitive behavioral therapy in public mental health: Comparison to

treatment as usual for treatment-resistant depression. Administration And Policy In Mental Health And Mental Health Services Research, doi:10.1007/s10488-014-0546-4

6. Simons, A. D., Padesky, C. A., Montemarano, J., Lewis, C. C., Murakami, J., Lamb, K., & Beck, A. T. (2010). Training and

dissemination of cognitive behavior therapy for depression in adults: A preliminary examination of therapist competence and client outcomes. Journal of Consulting And Clinical Psychology, 78(5), 751-756. doi:10.1037/a0020569

7. Meng, X., & D’Arcy, C. (2014). The projected effect of risk factor reduction on major

depression incidence: A 16-year longitudinal Canadian cohort of the national population health survey. Journal of Affective Disorders, 15, 56-61. doi: 10.1016/j.jad.2014.02.007

8. Hartlage, S., Alloy, L. B., Vazquez, C. & Dykman, B. (1993). Automatic and effortful processing in depression. Psychological

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