Depression is a state of low mood and aversion to activity that can have a negative effect on a person’s thoughts, behaviour, feelings, world view and physicalwell-being.[1] Depressed people may feel sad, anxious, empty, hopeless, worried, helpless, worthless, guilty, irritable, hurt or restless. They may lose interest in activities that once were pleasurable, experience loss of appetite or overeating, have problems concentrating, remembering details, or making decisions and may contemplate or attempt suicide. Insomnia, excessive sleeping, fatigue, loss of energy, or aches, pains or digestive problems that are resistant to treatment may also be present.[2]

Depressed mood is not necessarily a psychiatric disorder. It is a normal reaction to certain life events, a symptom of some medical conditions and a side effect of some medical treatments. Depressed mood is also a primary or associated feature of certain psychiatric syndromes such as clinical depression.

Life events

Life events and changes that may precipitate depressed mood include menopause, financial difficulties, job problems, relationship troubles, separation and bereavement.[3][4]

Medical treatments

Certain medications are known to cause depressed mood in a significant number of patients. These include Hepatitis C drug therapy and some drugs used to treat high blood pressure, such as beta-blockers or reserpine.

Non-psychiatric illnesses

Depressed mood can be the result of a number of infectious diseases and physiological problems including hypoandrogenism (in men), Addison’s disease, Lyme disease, multiple sclerosis, sleep apnea and disturbed circadian rhythm. It is often one of the early symptoms of hypothyroidism (reduced activity of the thyroid gland). Chronic pain causes depression. For a discussion of non-psychiatric conditions that can cause depressed mood, see Depression (differential diagnoses).

Psychiatric syndromes

A number of psychiatric syndromes feature depressed mood as a main symptom. The mood disorders are a group of disorders considered to be primary disturbances of mood. These include major depressive disorder (MDD; commonly called major depression or clinical depression) where a person has at least two weeks of depressed mood or a loss of interest or pleasure in nearly all activities; and dysthymia, a state of chronic depressed mood, the symptoms of which do not meet the severity of a major depressive episode. Another mood disorder, bipolar disorder, features one or more episodes of abnormally elevated energy levels, cognition and mood, but may also involve one or more depressive episodes.[5] When the course of depressive episodes follows a seasonal pattern, the disorder (major depressive disorder, bipolar disorder, etc.) may be described as a seasonal affective disorder.

Outside the mood disorders: borderline personality disorder commonly features depressed mood; adjustment disorder with depressed mood is a mood disturbance appearing as a psychological response to an identifiable event or stressor, in which the resulting emotional or behavioral symptoms are significant but do not meet the criteria for a major depressive episode;[6] and posttraumatic stress disorder, an anxiety disorder that sometimes follows trauma, is commonly accompanied by depressed mood.[7]


Main article: Rating scales for depression

A full patient medical history, physical assessment and thorough evaluation of symptoms helps determine the cause of the depression. Standardized questionnaires can be helpful such as the Hamilton Rating Scale for Depression,[8] and the Beck Depression Inventory.[9]

A doctor generally performs a medical examination and selected investigations to rule out other causes of symptoms. These include blood tests measuring TSHand thyroxine to exclude hypothyroidism, basic electrolytes and serum calcium to rule out a metabolic disturbance and a full blood count including ESR to rule out a systemic infection or chronic disease.[10] Adverse affective reactions to medications or alcohol misuse are often ruled out, as well. Testosterone levels may be evaluated to diagnose hypogonadism, a cause of depression in men.[11] Subjective cognitive complaints appear in older depressed people, but they can also be indicative of the onset of a dementing disorder, such as Alzheimer’s disease.[12][13]Cognitive testing and brain imaging can help distinguish depression from dementia.[14] A CT scan can exclude brain pathology in those with psychotic, rapid-onset or otherwise unusual symptoms.[15] No biological tests confirm major depression.[16] Investigations are not generally repeated for a subsequent episode unless there is a medical indication.

Depression in young adults

Depression in young adults is a common health problem and a growing public concern. In 2006, 1 in 20 U.S. adults had experienced a major depressive episode with severe impairment.[17] The Center for Disease Control and Prevention (CDC) reported that among ages 18–24, 2.8% met the criteria for major depression, 8.1% met the criteria for other depression (DSM-IV category Depressive Disorder, Not Otherwise Specified – minor or subthreshold depression, or Dysthymia) and 10.9% met the criteria for current depression.[18] Forty-four percent of American college students report feeling symptoms of depression.[19] This data suggests that traditional college aged students may be at high risk for depression or depressed mood.

Each year 44 colleges and universities use random sampling to administer the American College Health Association’s (ACHA) National College Health Assessment (NCHA) survey to 28,000 students. This assessment surveys students’ health status and behavior, including depression and depressive symptoms, for their previous academic year. Based on the findings, the rates of students reporting having been diagnosed with depression have increased from 10% in 2000[20] to 21% in 2011.[21] In 2011, female students reported depressive symptoms, including 22% feeling that things were hopeless, 23% feeling lonely and 26% feeling very sad within the preceding two weeks[20] to 21% in 2011.[21] Women are at higher risk than men to experience depression.[22]

  1. ^Salmans, Sandra (1997). Depression: Questions You Have – Answers You Need. People’s Medical Society. ISBN978-1-882606-14-6.
  2. ^“NIMH · Depression”. Retrieved 15 October 2012.
  3. ^Schmidt, Peter (2005). “Mood, Depression, and Reproductive Hormones in the Menopausal Transition”. The American Journal of Medicine.
  4. ^Life Events and Depression. Annals of Punjab Medical College. 2008 [cited 15 October 2012];2(1).
  5. ^Gabbard, Glen O.. Treatment of Psychiatric Disorders. 2 (3rd ed.). Washington, DC: American Psychiatric Publishing. p. 1296.
  6. ^American Psychiatric Association 2000a, p. 355
  7. ^Vieweg, W. V.; Fernandez, A.; Beatty-Brooks, M; Hettema, J. M.; Pandurangi, A. K. (May 2006). “Posttraumatic Stress Disorder: Clinical Features, Pathophysiology, and Treatment”. Am. J. Med.119 (5): 383–90. doi:10.1016/j.amjmed.2005.09.027. PMID 16651048.
  8. ^Zimmerman, M.; Chelminski, I; Posternak, M. (September 2004). “A Review of Studies of the Hamilton Depression Rating Scale in Healthy Controls: Implications for the Definition of Remission in Treatment Studies Of Depression.”. J Nerv Ment Dis192 (9): 595–601. PMID 15348975.
  9. ^McPherson, A.; Martin, C. R. (February 2010). “A Narrative Review of the Beck Depression Inventory (BDI) and Implications for its Use in an Alcohol-Dependent Population”. J Psychiatr Ment Health Nurs17 (1): 19–30. doi:10.1111/j.1365-2850.2009.01469.x. PMID 20100303.
  10. ^Do Psychiatrists Perform Appropriate Physical Investigations for Their Patients? A Review of Current Practices in a General Psychiatric Inpatient and Outpatient Setting. Journal of Mental Health. 2008;17(3):293–98. doi:10.1080/09638230701498325.
  11. ^Male Depression: A Review of Gender Concerns and Testosterone Therapy. Geriatrics. 2004;59(10):24–30. PMID 15508552.
  12. ^Subjective Memory Complaints and Cognitive Impairment in Older People. Dementia and Geriatric Cognitive Disorders. 2006;22(5–6):471–85.doi:10.1159/000096295. PMID 17047326.
  13. ^Diagnosis and Treatment of Depression in Patients with Alzheimer’s Disease and Other Dementias. The Journal of Clinical Psychiatry. 1998;59 Suppl 9:38–44. PMID 9720486.
  14. ^Distinguishing Between Depression and Dementia in Older Persons: Neuropsychological and Neuropathological Correlates. Journal of Geriatric Psychiatry and Neurology. 2007;20(4):189–98. doi:10.1177/0891988707308801. PMID 18004006.
  15. ^Sadock 2002, p. 108
  16. ^Sadock 2002, p. 260
  17. ^“Results from the 2007 National Survey on Drug Use and Health: National Findings”. Department of Health and Human Services Substance Abuse and Mental Health Services Administration Office of Applied Studies. Retrieved 25 April 2012.
  18. ^e%0d%0a#tab1 “Current Depression Among Adults – United States, 2006 and 2008”. Center for Disease Control and Prevention. e%0d%0a#tab1. Retrieved 12 March 2012.
  19. ^“Ranking America’s Mental Health: An Analysis of Depression Across the States”. Mental Health America. Retrieved 19 January 2012.
  20. ^ ab“Reference Group Data Report 2000”. American College Health Association National College Health Assessment. Retrieved 20 February 2012.
  21. ^ ab“Reference Group Data Report Spring 2011”. American College Health Association National College Health Assessment. Retrieved 20 February 2012.
  22. ^Nolen-Hoeksema, Susan (October 2001). “Gender Differences in Depression”. Current Directions in Psychological Science10 (5): 173–176.