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Depressive disorder
Last reviewed: 12.07.2025
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Depressive disorder is characterized by a depression of mood that is severe or lasts so long that functioning is impaired, and sometimes by a decrease in interest in or ability to enjoy activities. The exact cause is unknown, but heredity, changes in neurotransmitter levels, abnormal neuroendocrine functioning, and psychosocial factors probably play a role. Diagnosis is based on the patient's history. Treatment usually involves medication, psychotherapy, a combination of the two, and sometimes electroconvulsive therapy.
The term "depression" is often used to refer to a number of depressive disorders. Three of these are recognized in the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) by specific symptoms: major depressive disorder (often called major depression), dysthymia, and depressive disorder not elsewhere classified. The other two are recognized by etiology: depressive disorder due to a general medical condition and medication-induced depressive disorder.
Depressive disorder occurs at various ages, but most often develops in middle age, in the 20-30 year olds. In primary care, about 30% of patients report depressive symptoms, but major depression is observed in less than 10%.
The term depression is often used to describe a low or depressed mood due to disappointment or loss. In English, the term used to describe this mood is demoralization. Unlike depression, the negative emotions of this condition subside when the situation that caused them improves; the low mood typically lasts for days rather than weeks or months, and suicidal ideation and long-term loss of normal functioning are much less likely.
[ Cause of depressive disorder
The exact cause of depressive disorder is unknown. Heredity plays an unclear role; depression is more common among first-degree relatives of a patient with depression, and concordance is high between monozygotic twins. An inherited genetic polymorphism in the activity of the serotonin transporter in the brain may be triggered by stress. People who experienced childhood abuse or other severe stress and who have the short allele of this transporter are twice as likely to develop depression compared to those who have the long allele.
Symptoms of depressive disorder
Depression is characterized not only by low mood but also by cognitive, psychomotor, and other disturbances (e.g., poor concentration, fatigue, loss of sexual desire, menstrual irregularities). Other psychiatric symptoms or disorders (e.g., anxiety or panic attacks) often coexist with depression, sometimes complicating diagnosis and treatment. Patients with all forms of depression are likely to abuse alcohol and other psychoactive substances to self-medicate sleep disturbances or anxiety symptoms; however, depression is less likely to cause alcoholism and substance abuse than is commonly believed.
Diagnosis of depressive disorder
The diagnosis of depressive disorder is based on the identification of the symptoms and signs described above. There are a number of short screening questionnaires. They help in identifying some depressive symptoms, but cannot be used in isolation to establish a diagnosis. Specific closed questions help in identifying the patient's symptoms required by the DSM-IV criteria for a diagnosis of major depression.
The severity of the condition is determined by the degree of suffering and impairment of functioning (physical, social and professional), as well as the duration of symptoms. The presence of suicidal risk (manifested in suicidal thoughts, plans or attempts) indicates the severity of the disorder.
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Prognosis and treatment of depressive disorder
With appropriate treatment, symptoms often resolve. Mild depression can be treated with general support and psychotherapy. Moderate to severe depression is treated with medication, psychotherapy, or a combination of both, and sometimes electroconvulsive therapy. Some patients require more than one medication or combination of medications. Improvement may require 1 to 4 weeks of medication at the recommended dose. Depression tends to recur, especially in patients who have had more than one episode; therefore, long-term maintenance medication is needed in severe cases.
Most patients with depression are treated on an outpatient basis. Patients with severe suicidal intent, especially with insufficient family support, require hospitalization; hospitalization is also necessary if psychotic symptoms or physical exhaustion are present.
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