• Depression is a common, serious and costly illness that affects 1 in 10 adults in the U.S. each year, costs the Nation between $30 - $44 billion annually, and causes impairment, suffering, and disruption of personal, family, and work life.
• Though 80 percent of depressed people can be effectively treated, nearly two out of three of those suffering from this illness do not seek or receive appropriate treatment. Effective treatments include both medication and psychotherapy, which are sometimes used in combination.

Of particular significance, depression often co-occurs with medical, psychiatric, and substance abuse disorders. When this happens, the presence of both illnesses is frequently unrecognized and may lead to serious and unnecessary consequences for patients and families.

Depression Co-occurs With Medical Illnesses

The rate of major depression among those with medical illnesses is significant. In primary care, estimates range from 5 to 10 percent; among medical inpatients, the rate is 10 to 14 percent.

Depressed feelings can be a common reaction to many medical illnesses. However, depression severe enough to receive a psychiatric diagnosis is not the expected reaction to medical illness. For that reason, when present, specific treatment should be considered for clinical depression even in the presence of another disorder.

Research has shown that major depression occurs in:

• Between 40 and 65 percent of patients who have had a myocardial infarction (MI). They may also have a shorter life expectancy than non-depressed MI patients.
• Approximately 25 percent of cancer patients.
• Between 10 and 27 percent of post-stroke patients.

Failure to recognize and treat co-occurring depression may result in increased impairment and diminished improvement in the medical disorder.

Proper diagnosis and treatment of co-occurring depression may bring benefits to the patient through improved medical status, enhanced quality of life, a reduction in the degree of pain and disability, and improved treatment compliance and cooperation.

Depression Co-occurs With Psychiatric Disorders

A higher than average co-occurrence of depression with other psychiatric disorders, such as anxiety and eating disorders, has been documented.

• Concurrent depression is present in 13 percent of patients with panic disorder. In about 25 percent of these patients, the panic disorder preceded the depressive disorder.
• Between 50 and 75 percent of eating disorder patients (anorexia nervosa and bulimia) have a lifetime history of major depressive disorder.

In such cases, detection of depression can help clarify the initial diagnosis and may result in more effective treatment and better outcome for the patient.

Depression Co-occurs With Substance Abuse Disorders

Substance abuse disorders (both alcohol and other substances) frequently co-exist with depression.

• Substance abuse disorders are present in 32 percent of individuals with depressive disorders. They co-occur in 27 percent of those with major depression and 56 percent of those with bipolar disorder.

Substance use must be discontinued in order to clarify the diagnoses and maximize the effectiveness of psychiatric interventions. Treatment for depression as a separate condition is necessary if the depression remains after the substance use problem is ended.

Action Steps

DON'T IGNORE SYMPTOMS! Health care professionals should be aware of the possibility of depression co-occurring with other illnesses. Individuals or family members with concerns about the co-occurrence of depression should discuss these issues with the physician. A consultation with a psychiatrist or other mental health clinician may be recommended to clarify the diagnosis.

co-occurrence index

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