Update on the diagnosis and treatment of depression

Medicine and Health Rhode Island, Oct 2003 by Attiullah, Naureen, Zimmerman, Mark

Depressive symptoms are one of the most common and disabling medical problems seen in a primary care practice. In the United States about 75% of people who seek help for depression go to a primary care physician rather than to a mental health professional; yet the diagnosis of depression may be missed in one-third to one-half of patients.1 Furthermore, although physicians are taught to ask about suicide in a mental status exam, many physicians often do not inquire about suicidal thoughts, even in patients they have identified as depressed.2

The management of depression in the outpatient setting requires the establishment of a diagnosis, initiation of treatment, continuation and maintenance of treatment, or referral when appropriate.

Barriers to the diagnosis of depression

Because of the stigma associated with psychiatric illness, many patients are reluctant to acknowledge their distress: they minimize symptoms of depression, rationalize them as related to a life stress or medical condition, believe them to be failures of willpower or moral shortcomings, and do not see them as treatable. Family and cultural beliefs may reinforce such attitudes. Likewise, some physicians believe that depression is not a "real illness," that it reflects a personal shortcoming or laziness, that the patient could improve with more effort, willpower or "positive thinking."

Even knowledgeable physicians sometimes cannot elicit an accurate history from the patient. A highly focused closed-ended interviewing technique may not encourage patients to bring up psychosocial issues. In addition, the physician may fail to recognize non-verbal cues and ask follow-up questions when the patient seems distressed.

DIAGNOSTIC DEPRESSION

A depressed mood is not synonymous with a major depressive episode. Patients may complain of sadness, which may be a normal reaction to a loss or stress. Major Depressive Disorder is diagnosed when a person experiences a minimum of five of the following symptoms every day, or nearly every day, for at least two weeks:

1. depressed mood most of the day

2. loss of interest or pleasure in formerly pleasurable activities

3. significant decrease or increase in appetite

4. problems sleeping at night, or sleeping too many hours per day

5. feeling very physically restless and agitated, or physically slowed down

6. fatigue or loss of energy

7. feeling worthless or excessively guilty

8. problems concentrating or making decisions

9. recurrent thoughts of death or suicide

In medical settings depression often does not present with a mood complaint, but with somatic symptoms; e.g., back pain, headache, fatigue, sleep disturbance, or appetite disturbance. Insomnia, especially early morning awakening, is one of the classic and most dependable early symptoms of depression. Patients complaining of persistent insomnia are more likely to develop depression within 1 year than patients without persistent insomnia.3

Even a prominent mood may not be described as "depressed", but as "irritable" or "anxious." Therefore a high index of suspicion, previous knowledge of the patient and awareness of risk factors assist in making an early and accurate diagnosis. One of the most significant risk factors is a family history of depression. The incidence of depression is two to three times higher if a first-degree relative has been affected. The genetic basis of depression is well established in adoption and twin studies. For monozygotic twins the concordance rate is approximately 65%; for dizygotic twins it is about 15%.4

Half of individuals with one episode of depression have another.5 The likelihood of relapse is 80% in persons with two prior episodes, above 90% in persons with three or more prior episodes. Thus, it is important to be vigilant for recurrence of depressive episodes in patients with a history of depression. Risk factors for a recurrence include number of previous episodes, long duration of individual episodes, substance abuse, associated anxiety disorder and an underlying dysthymic disorder. Also, sleep progressively worsens several weeks before the recurrence of depression.

Differential diagnosis

At least 10% of depressed patients have a history of mania or hypomania and are diagnosed with bipolar disorder. It is important to evaluate for a history of mania in all depressed patients (and family members) because antidepressant medication alone would not be the treatment of choice. In fact, antidepressants can precipitate a manic episode in vulnerable individuals. Mania is characterized by elevated mood, grandiosity, decreased need for sleep, racing thoughts, pressured speech, distractibility, and impulsive risky behaviors. Bipolar disorder is sometimes difficult to diagnose because the diagnosis is based on the patient's retrospective report of manic episodes.

Because substance use disorders can mimic a depressive syndrome, clinicians should screen for drug and alcohol use. Likewise, some medical disorders such as thyroid and adrenal disorders may cause depression phenotypes. When the symptoms of depression can be attributed to a medical illness, the appropriate diagnosis is depressive disorder due to a general medical condition. This is in contrast to the situation where a patient is depressed because of a medical illness and only some of the depression symptoms are due to that illness. This latter situation is sometimes the cause of under-diagnosing and under-treating depression. The patient with cancer is thought to be "understandably" depressed, and symptoms of fatigue and appetite loss may be due to the cancer. Studies of oncology patients have compared different approaches towards diagnosing depression-an inclusive approach in which symptoms are counted regardless of their possible etiology, an exclusive approach in which symptoms likely due to the cancer are not counted towards the diagnosis of depression, and a substitution approach in which the depression criteria have been reworked and psychological symptoms such as hopelessness replace physical symptoms such as fatigue. These studies suggest the inclusive approach towards applying the DSM-IV diagnostic criteria is as, if not more, valid than other methods of diagnosing depression.6