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Source: Teter CJ, Kando JC, Wells BG. Major depressive disorder. In: DiPiro JT, Talbert RL, Yee GC, Matzke GR, Wells BG, Posey LM, eds. Pharmacotherapy: A Pathophysiologic Approach. 10th ed. New York, NY: McGraw-Hill; 2017. http://accesspharmacy.mhmedical.com/content.aspx?bookid=1861§ionid=146064868.
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CONDITION/DISORDER SYNONYMS
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Unipolar depression.
Major depression.
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Several social, developmental, and biologic theories proposed.
Patient symptoms reflect changes in brain monoamine neurotransmitters, specifically norepinephrine (NE), serotonin (5-HT), and dopamine (DA).
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Depression may be caused by decreased brain levels of norepinephrine, 5-HT, and dopamine.
Desensitization or downregulation of norepinephrine or 5-HT1A receptors may relate to onset of antidepressant effects.
Failure of homeostatic regulation of neurotransmitter systems, rather than absolute increases or decreases in their activities, may be involved.
Potential link between 5-HT and norepinephrine activity—both serotonergic and noradrenergic systems involved in antidepressant response.
Increased dopamine neurotransmission in mesolimbic pathway may be related to mechanism of action of antidepressants.
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In one survey, 16.2% of population had history of major depressive disorder in their lifetime, and >6.6% had episode within past 12 months.
Women have lifetime rate 1.7–2.7 times greater than for men.
Adults 18–29 years of age have highest rates during any given year.
Depressive disorders common during adolescence, with comorbid substance abuse, suicide attempts, and deaths occurring frequently.
Depressive disorders and suicide tend to occur within families.
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CLINICAL PRESENTATION
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MEANS OF CONFIRMATION AND DIAGNOSIS
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Documenting one or more episodes of major depression, as defined by Diagnostic and Statistical Manual of Mental Disorders, 5th ed.
Symptoms present nearly every day for at least 2 weeks.
When patient presents with depressive symptoms, investigate possibility of medical, psychiatric, or drug-induced cause.
Perform complete medication review, physical examination, mental status examination.
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DIFFERENTIAL DIAGNOSIS
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