Depression

I. Background
A. Definition
Depression is an illness that affects the mind, body, mood, thoughts, and relationships. It is not just unhappiness but an overwhelming sense of sadness and physical decline that has potential far-reaching deleterious effects.
B. Cost
Depression costs the United States billions of dollars annually in lost productivity and direct medical costs. Health service costs are 50% to 100% greater for depressed patients compared to patients without depression. These increased costs are due to higher medical utilization and not due to speciality mental health care (1). Depression also contributes to impaired concentration, failure to advance in education and vocational endeavors, increased substance abuse, impaired or lost relationships, and increased risk of suicide (2).
II. Pathophysiology
A. Etiology
The biopsychosocial model is an effective way to conceptualize the etiology of anxiety and depression because the factors that create anxiety and depression are varied. The interplay between the biologic, psychological, and social aspects of the particular patient should be assessed to determine the etiology of the disease.
  • Biologic There is ample information suggesting that genetics plays a role in the development of mood disorders. Studies related to twins have shown that the rate of mood disorders in identical twins is 67% to 76% but only 19% in fraternal twins (3). Women are at least twice as likely to suffer from depression as men. Individuals with a family history of mood disorders are at a higher risk of developing a disorder themselves. Other important biological factors include comorbidities or depression as a result of medical problems and abuse of substances, which may be either the cause or the symptom of the depression.
  • Psychological Individuals who are continually under a great deal of stress, have a negative outlook on life, or a passive temperament are more likely to suffer from a mood disorder. These individuals often engage in cognitive distortions, including unrealistic expectations, overgeneralizing adverse events, personalizing negative or difficult events, and overreacting to stressors. Behaviorally, individuals who are continually under stress often believe that any action on their part would be futile, and therefore they continue to repeat self-defeating or problematic behaviors or do nothing at all (learned helplessness).
  • Social There are many social influences that are related to mood disorders. These include difficult marriages, divorce, problems with children, family and community violence, and economic difficulties. Many individuals do not have the social resources (e.g., friendships, family, community) or buffers that aid in coping (e.g., spirituality).
B. Epidemiology
Depression is one of the most common conditions seen in primary care. Reliable estimates suggest that depressive symptoms are present in approximately 70% of patients who visit primary care providers with approximately 15% to 20% of these patients suffering from major depression (4). The prevalence of major depression is two to three times higher in general medical practice than in the overall population. However, physicians often underdiagnose patients with depression. Even among patients correctly diagnosed, most patients with depression still do not receive treatment concordant with recommended guidelines. Further, patient adherence to the recommended treatment plan is low (5).
III. Evaluation
A. History
To be diagnosed with major depression, an individual must have experienced over the same two-week period five or more symptoms and must have depressed mood and/or anhedonia. The mnemonic SIGECAPS highlights the symptoms of a major depressive episode:
  • Sleep disturbance -- early morning awakenings or restless sleep
  • Interest -- little interest in activities they used to enjoy (anhedonia)
  • Guilt -- feeling guilty or worthless
  • Energy -- feeling tired or fatigued
  • Concentration -- impaired concentration and/or indecisiveness
  • Appetite -- weight change and/or changes in their normal eating patterns (eating less or more than usual)
  • Psychomotor disturbance -- any psychomotor agitation or retardation
  • Suicidal thoughts -- recurrent thoughts of death, suicidal ideation, and suicide attempt.
B. Physical examination
Any patient with depression severe enough to warrant treatment should have both a general screening physical examination (paying particular attention to signs of anemia and endocrinopathies [e.g., hypothyroidism]) and a careful screening neurologic examination. Depression is also often a symptom of many medical conditions that are related to depressive disorders (e.g., cardiovascular disease, multiple sclerosis, cancer, thyroid disorders, acquired immunodeficiency syndrome, endocrine changes).
C. Testing
Laboratory tests should be ordered on the basis of the history and examination findings (e.g., complete blood count for anemia, thyroid-stimulating hormone for thyroid disorders).
  • Multiple screening instruments can be used to detect depression (i.e., Zung, Beck depression inventory). A relatively new screening tool that has been found to be efficient and effective in determining depression severity is the Patient Health Questionnaire-9 (PHQ-9)(6). The PHQ-9 is a screening questionnaire chosen because of the ease of administration, scoring, and its high sensitivity/specificity. The PHQ-9 is a 9-question form that addresses all the symptoms of major depression (6). Questions are answered using a 4-point-Likert scale (0 = not at all and 3 = nearly everyday). Scores of 5 to 9 are associated with mild depression, and scores of 10 or above are associated with moderate or severe depression (7).
  • The U. S. Preventive Services Task Force (8) recommends screening adults for depression in clinical practice. A quick two question screen for depression can be used to identify individuals at risk: over the past two weeks have you (a) felt down, depressed, or hopeless? and (b) felt little interest or pleasure in doing things? If an individual answers yes to one or both of these, he/she should be further evaluated for depression.
IV. Diagnosis
A. Differential diagnosis
  • In addition to the medical conditions related to depression discussed earlier, each individual suspected of depression should also be screened for anxiety disorders, alcohol and drug abuse, suicidality, homicidality, and domestic violence or perpetration of abuse.
  • There are many types of depressive disorders. It is important to distinguish the specific type of disorder so as to most effectively recommend treatment options.
    • Major Depressive Disorder is present when the individual has two or more major depressive episodes.
    • Dysthymic Disorder is characterized by at least two years of low-grade depression
      (does not meet the criteria for a major depressive episode).
    • Depressive Disorder Not Otherwise Specified is used when the individual does not meet criteria for other depressive conditions, but depressive features exist.
    • Bipolar I Disorder is characterized by one or more manic episodes and is usually accompanied by major depressive episodes. It is important to rule out mania in individuals who are depressed because psychopharmalogical treatment of depression can make individuals with Bipolar disorder become manic. Manic episodes must include at least three of the following symptoms lasting for a period of at least seven days:
      • inflated self-esteem or grandiosity
      • decreased need for sleep
      • more talkative than usual or pressure to keep talking
      • flight of ideas or subjective experience of thoughts racing
      • distractibility
      • increase in goal-directed activity (socially, at work, or sexually) or psychomotor agitation
      • excessive involvement in pleasurable activities that have a high potential for painful consequences (e.g., spending, gambling, sexual indiscretions).
    • Bipolar II Disorder is characterized by one or more major depressive episodes and at least one hypomanic episode (lasting at least four days). Hypomanic episodes use the same criteria as manic episodes, but hypomania does not cause marked impairment in social or occupational functioning or require hospitalization.
    • Cyclothymic Disorder is characterized by at least two years of numerous periods of low-grade depression and hypomanic symptoms.
    • Mood Disorder Due to a General Medical Condition and Substance-Induced Mood Disorder are characterized by a mood disturbance caused by the direct physiological consequence of either a general medical condition or substance use, respectively.
    • Seasonal Affective Disorder, Grief Reaction, and Adjustment Disorder with Depressed Mood are other disorders that are caused by the time of the year, response to loss, and response to a significant change (e.g., divorce), respectively.
B. Clinical manifestations
  • Depression does not often present in a primary care setting by the patient complaining of depressed mood. More likely the patient will discuss the symptoms of depression (e.g., fatigue, insomnia, gastrointestinal upset). It is therefore important for the physician to not only attend to the physical complaints but also probe into the emotional symptoms (e.g., dysphoria, anhedonia).
  • The treatment of depressive disorders is important. On the basis of the biopsychosocial model, treatment modalities that address the biologic, psychological, and social aspects of the individual difficulties have been found to be the most effective. Creating a treatment plan tailored to the individuals' needs, including addressing the use of psychotherapy (cognitive-behavioral or interpersonal), marital therapy, medication, and exercise, have been found to be most effective.
References
1. Henk HJ, Katzelnick DJ, Kobak KA, et al. Medical costs attributed to depression among patients with a history of high medical expenses in a health maintenance organization. Arch Gen Psychiatry 1996;53(10):899 - 904.
2. Pincus HA, Pettit AR. The societal costs of chronic major depression. J Clin Psychiatry 2001;62(S6):5 - 9.
3. Papolos D, Papolos J. Overcoming depression, 3rd ed. New York: HarperCollins, 1997.
4. Montano CB, Montano MB. A new paradigm for treating depression in the primary care setting. Medical Education Collaborative, at: http://www.medscape.com, accessed on October 10, 2004.
5. Young AS, Klap R, Sherbourne CD, et al. The quality of care for depressive and anxiety disorders in the United States. Arch Gen Psychiatry 2001;58(1):55 - 61.
6. Kroenke K, Spitzer RL, Williams JBW. Validity of a brief depression severity measure. J Gen Intern Med 2001;16(9):606 - 613.
7. The MacArthur Initiative on Depression and Primary Care. Tool Kit, at: http://www.depression-primarycare.org, accessed on July 22, 2005.
8. U. S. Preventive Services Task Force. Screening for depression: recommendations and rationale. Ann Intern Med 2002;136(10):760 - 764.

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