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Last Updated: Mar 1, 2019


Depression is a mood disorder characterized by debilitating feelings of sadness and hopelessness that interfere with normal activities of day-to-day life. Depression commonly develops in young adults and adolescents, but the disorder can also occur in children.

Types of Depression


A combination of various factors can trigger people to develop depression. Such factors include genetic predisposition, environmental factors, hormones, brain chemicals (neurotransmitters), trauma, relationship problems, and stressful life events (such as divorce or loss of a job). For unknown reasons, women have a much higher risk of developing depression than men.

Studies have shown that certain areas of the brain that shape our mood, memory and behavior can have an altered appearance in those suffering from depression. For instance, some studies have revealed the hippocampus to be physically smaller in people with depression, and suggest that the degree to which it is smaller may correspond to the frequency of symptoms. Whether these physical changes in part lead to depression or are instead an effect of the disorder is still undetermined.

Frequently, people with serious medical problems also have depression. Neurological disorders, thyroid diseases, cancer, infections, and metabolic disorders often lead to depression symptoms.

hippocampus highlighted in the brain


Common signs and symptoms of depression include the following:


In some patients, depression is difficult to diagnose because it may mimic other medical conditions. Major depression is often unrecognized in the elderly, for whom the disorder is frequently mistaken for the signs and symptoms of aging. When depression is suspected, a physical examination and lab tests should be performed to rule out a medical illness.

A psychiatric assessment includes a thorough evaluation of a patient’s thoughts and behaviors; history of other psychiatric disorders; current stressors; major life events; occupational history; relationships; family history of mental illness; and use of illicit substances and alcohol. Special attention is given to the presence of thoughts about suicide and signs of poor self-care.


Whether patients with depression are treated in a hospital or an outpatient setting depends on the severity of their symptoms and their risk of harming themselves or others. Hospitalization is frequently indicated for patients who are deemed at a high risk of suicide or have extremely impaired self-care.

Antidepressant Medication

The choice of antidepressant medication depends on the drug’s side effects and a patient’s response to treatment. Usually patients need 4 to 6 weeks of treatment before a physician can determine whether a specific therapy is effective. Research shows that some patients, especially adolescents, may have an increased risk of developing suicidal thoughts while taking antidepressant medications, so patients need to be carefully monitored after any medication is initiated.


Psychotherapy is also called talk therapy, and for some patients with mild to moderate forms of depression, psychotherapy alone is the initial treatment. A combination of antidepressant medication and psychotherapy is usually required for patients with moderate to severe forms of depression.

Other Therapies

Lifestyle Changes

Patients are advised to engage in regular exercise, which has been shown to significantly reduce depression symptoms. Additionally, proper sleep and diet are recommended. Patients with depression should avoid alcohol and illicit substances.

Alternative Medicine

S-adenosyl methionine (SAMe) and St. John’s wort may help reduce mild forms of depression. These over-the-counter treatments are associated with potential risks, and more research is needed to determine their efficacy.

Education of the Family

With the patient’s consent, family members are educated about depression and early signs of relapse. Patients with supportive relationships tend to achieve better outcomes.


Although there is no specific method of preventing depression, patients may decrease the risk for major depression by controlling stress and maintaining relationships with family and friends. Individuals with early signs of depression should be treated promptly to prevent severe debilitation.


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Tina Shahian, PhD

Tina is a writer for Innerbody Research, where she has written a large body of informative guides about health conditions.


A communication specialist in life science and biotech subjects, Tina’s successful career is rooted in her ability to convey complex scientific topics to diverse audiences. Tina earned her PhD in Biochemistry from the University of California, San Francisco and her BS degree in Cell Biology from U.C. Davis. Tina Shahian’s Linkedin profile.


In her spare time, Tina enjoys drawing science-related cartoons.