Depression

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Abstract

Editor's Note: This issue of In the Clinic has been updated. Depression is common in primary care, affecting 5% to 10% of patients in this setting (1). Untreated depression may be a barrier to effective treatment of common co-occurring illnesses (e.g., diabetes and cardiovascular disease) (2). The disability associated with depression is similar to that of other chronic medical conditions (3). Depression is currently the fourth leading contributor to the global burden of disease (as measured using disability-adjusted life-years) and will move into second place by 2020 (4). Effective treatment of depression reduces symptoms and improves quality of life (5). Although sometimes viewed as "opening Pandora’s box," primary care clinicians can efficiently identify and manage most cases of depression. Screening Which patients are at especially high risk for depression? Screening limited to high-risk adults (i.e., case-finding) may be more cost-effective than screening all adults. Risk factors for depression include older age (6) and associated neurologic conditions, recent childbirth (7), stressful life events (8), a personal or family history of depression, and selected medical comorbid conditions (9) (Table 1). Suicide rates are twice as high in families of suicide victims (10). Table 1. Risk Factors for Depression Should clinicians screen for depression? A 2002 U.S. Preventive Services Task Force reviewed 14 randomized, controlled trials examining the effectiveness of screening for depression in primary care. This guideline recommends screening adults for depression in clinical practices that have "systems in place to assure accurate diagnosis, effective treatment, and follow-up" (1). Depression screening instruments do not diagnose depression but do accurately identify patients at risk. All positive screening tests should trigger a full diagnostic interview to determine the presence or absence of specific depressive disorders. A meta-analysis of screening studies suggested that screening is associated with a 9% absolute reduction in the proportion of patients with persistent depression at 6 months. Assuming a prevalence of 10%, 110 primary care patients would need to be screened for depression to produce 1 additional remission (1). How often should clinicians screen for depression? The optimal interval for screening is unknown. Based on expert recommendations, clinicians should consider screening patients with identified risk factors (Table 1) and those with several unexplained or unrelated somatic symptoms, comorbid psychological conditions (e.g., panic disorder or generalized anxiety), substance abuse, chronic pain, or lack of response to usually effective treatments for comorbid medical conditions (11). What methods should clinicians use to screen for depression? A positive response to a 2-item instrument (see the Box on the next page) had a sensitivity of 96% and a specificity of 57%. Screening Questions for Depression "Over the past 2 weeks have you felt down, depressed, hopeless?" "Over the past 2 weeks have you felt little interest or pleasure in doing things?" Patients with a positive response to 1 or both questions (i.e., those with depressed mood and/or anhedonia) should undergo a full diagnostic interview to assess whether they meet the criteria for depression disorders as set forth in the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV) (see Table 3 in Diagnosis). A meta-analysis of 9 case-finding instruments in 18 studies and a head-to-head study of screening instruments showed that the 2-question instrument is as good as many of the longer instruments (12). Many other screening tools, targeted to specific populations, are available (Table 2). The most commonly used screening tools in adults include the Beck Depression Inventory Scales II, the Center for Epidemiologic Studies Depression Scale-Revised, and the Zung Self-Rating Depression Scale. The Edinburgh Postnatal Depression Scale was specifically developed to assess postpartum depression (12-14). In the elderly, cognitive impairment can limit the utility of screening instruments and should be assessed with the Mini-Mental State Examination. In patients with cognitive deficits, clinicians should consider the interviewer-administered Cornell Scale for Depression in Dementia or the Hamilton Rating Scale (15, 16). Several tools are available in non-English versions. The Hopkins Symptom Checklist-25 has been validated in refugee populations and is available in many languages. Table 2. Screening Measures for Depression Clinical Bottom Line: Screening Clinicians should screen for depression as the first step in a systematic evaluation of mood disorders in all adults. Adults who are older, are postpartum, have a personal or family history of depression, or have comorbid medical illness are at increased risk. There is little evidence to recommend one screening method over another, so physicians can choose the method that best suits their patient population and practice setting. The 2-question instrument is more efficient and performs as well as longer instruments. Diagnosis What are the diagnostic criteria for depression? Depression is diagnosed when 5 or more DSM-IV symptoms occur in the same 2-week period in conjunction with a change from previous functioning (Table 3) (17). At least one of the symptoms must be either depressed mood or anhedonia, as reflected in the 2-question depression screening model mentioned earlier. An alternative strategy for diagnosing major depressive disorders is to follow the 2-item (mood and anhedonia) case-finding questions with assessment of the so-called SALSA inventory: Sleep disturbance Anhedonia Low Self-esteem Appetite disturbance Table 3. Criteria for Major Depressive Episode on the Basis of the Diagnostic and Statistical Manual of Mental Disorders Patients with 2 of these 4 symptoms occurring nearly every day for at least 2 weeks are virtually identical to those diagnosed using the 5-out-of-9-symptom algorithm in Table 3. Over 97% of patients with major depression have at least 2 of the SALSA symptoms. Only 6% of persons who do not have major depression will have 2 of the SALSA symptoms (18). How can clinicians determine the severity of depression? Assessment of depressive symptom severity helps guide treatment. Mild to moderate depression responds equally well to either medication or psychotherapy (19). Patients with severe major depressive disorder benefit more from antidepressant medication or from medication combined with psychotherapy than from psychotherapy alone. The self-administered 9-item Patient Health Questionnaire (PHQ-9) is easily scored to quantify the severity of depression (Table 4) (20). Items 1 through 9 are summed to yield a scale score ranging from 0 to 27. Table 4. Patient Health Questionnaire-9 On this scale, 0 to 4 is considered non-depressed, 5 to 9 mild depression, 10 to 14 moderate depression, 15 to 19 moderately severe depression, and 20 to 27 severe depression. The 9 items reflect the 9 DSM-IV criteria. Item 10 assesses functional impairment. Like symptom severity, severe functional impairment may suggest the need for hospitalization and psychiatric consultation (21). How can clinicians and patients distinguish between normal reactions to life events and depression? Situational adjustment reaction with depressed mood is subsyndromal depression with a clear precipitant. Subsyndromal (minor) depression is characterized by 2 to 4 DSM-IV depressive symptoms, including depressed mood or anhedonia, for more than 2 weeks (Table 3). Adjustment disorder usually abates with resolution of the stressor, but careful observation and supportive counseling are indicated. Differentiating normal grieving and pathologic grief from depression can be difficult. The syndrome of major depression may be transiently present in normal grief; however, sadness without the complete syndrome is more common. Transient hallucinations (hearing or seeing the deceased person) or suicidal thoughts (feeling that one would be better off dead or should have died with the deceased person) are considered a normal part of grief. The boundaries of normal grief are affected by cultural and societal factors. Symptoms suggestive of depression include inappropriate guilt, persistent thoughts of death, morbid preoccupation with worthlessness, marked psychomotor retardation, prolonged functional impairment, and hallucinations. Patients whose symptoms persist beyond 2 months should be evaluated for depression. What alternative medical or psychiatric disorders should clinicians consider when evaluating patients with symptoms of depression? Certain medications and comorbid conditions are known to be associated with clinical depression. Glucocorticoids, interferon, l-dopa, propanolol, and oral contraceptives are the most commonly implicated medications. Data on isotretinoin remain unclear (22). The clinical situation will guide the clinician in choosing to discontinue the suspected agent or to add antidepressant therapy. Depression can be a manifestation of hypothyroidism, Cushing disease, or cobalamin deficiency, and depression can co-occur with diabetes, stroke, and myocardial infarction (23-28). It can also be associated with somatization, anxiety, domestic violence, cognitive dysfunction, and alcohol dependence. How should clinicians assess a depressed patient’s risk for self-harm, including suicide? Each year, more than 30,000 Americans commit suicide. Mental and addictive disorders, such as alcohol abuse, are the most powerful risk factors for suicide in all age groups, accounting for over 90% of all suicides (29). In evaluating a patient with major depression, previous suicide attempts should be considered the best predictor of completed suicide (30). Most patients who commit suicide have seen a physician in the preceding months. Clinicians should assess for suicidal intent at each visit for depression.