Guideline: 6 Detection of Depression Clinical Clues Major depressive disorder is common in primary care outpatients (4 to 8 percent), and nonmajor forms are even more common (6 to 14 percent). Both recognition and diagnosis of depression rest on an awareness of risk factors for depression, as well as elicitation of the key signs, symptoms, and history of illness. The primary risk factors for depression are: ■ Prior episodes of depression. ■ Family history of depressive disorder. ■ Prior suicide attempts. ■ Female gender. ■ Age of onset under 40. ■ Postpartum period. ■ Medical co-morbidity. Lack of social support. Current alcohol or substance abuse. A variety of clinical clues may further alert the practitioner to the likelihood of a mood disorder. Guideline: A history of major depressive episodes increases risk for subsequent major depressive episodes. (Strength of Evidence = A.) One major depressive episode is associated with a 50 percent chance of a subsequent episode; two episodes, with a 70 percent chance of a subsequent episode; and three or more episodes, with a 90 percent chance of recurrent depression over a lifetime (NIMH Consensus Development Conference, 1985). Guideline: A history of mood disorders in first-degree relatives increases the probability of a patient's developing a mood disorder. (Strength of Evidence = A.) First-degree relatives of bipolar disorder patients are at substantially higher risk for developing either a recurrent major depressive disorder (roughly 12 percent) or bipolar disorder (roughly 12 percent). Strong scientific evidence points to a genetic vulnerability to bipolar disorder. For those with more recurrent forms of major depressive disorder, genetic factors also appear to play a significant role. For those with less recurrent forms of major depressive disorder, the role of genetic factors is unclear. It is known, however, that patients who develop major depressive disorder before age 20 have a greater familial morbidity for depression (Goodwin and Jamison, 1990). Guideline: A history of suicide attempts should trigger the practitioner to inquire specifically about depressive symptoms. (Strength of Evidence = A.) Suicide attempts are frequently associated with mood disorders. In addition, a history of suicidal ideation and/or attempts increases the patient's risk for subsequent suicidal ideation/attempts. Additional risk factors for suicide include: The signs and symptoms of depression can be sought by direct interview, which may be supplemented with self-report ratings and/or by a history obtained from the patient's spouse or a friend. Depressive disorder is diagnosed on the basis of positive evidence—not by exclusion. For example, patients with or without other general medical conditions either do or do not have a depressive syndrome. Depression should not be explained away or discounted as a commonplace "reaction" to the concurrent general medical condition. Similarly, life events, including losses of important people or key roles, usually precede the onset of major depressive episodes. Thus, the presence of selected untoward life events should not be used to explain away the major mood episode. Guideline: The clinical interview is the most effective method for detecting depression. The interview elicits the nine criterion symptoms of major depressive disorder and the longitudinal course of illness. Similarly, interviewing for symptoms and course of illness is essential to identifying bipolar, dysthymic, and other mood disorders. Specific questions regarding the criterion symptoms are asked. Since either a depressed, blue, or sad mood or a loss of interest or pleasure is required, these symptoms are elicited first. The clinician who suspects or diagnoses a depressive disorder is advised to perform and record the results of a mental status examination, which includes whether the patient has suicidal ideation/intention; is oriented, alert, cooperative, and communicative; exhibits a normal level of motor activity; and is psychotic. (Strength of Evidence = A.) Some patients may initially deny the depressed mood, but may identify the somatic symptoms (sleep, appetite, and weight changes). Upon further discussion, the interviewer should return to the issues of mood and interest. Patients may initially complain about sleep, appetite, energy, concentration, and sex drive changes or about chronic or intermittent pain or anxiety. The clinician should be alert to considering the diagnosis of depressive illness in these patients. If symptoms of depression are present, it is important to determine their time course. How long has the patient been in an episode of major depressive disorder? Were there prior episodes? What degree of interepisode recovery has occurred? How severe are the current symptoms? The more severe forms of depression, characterized by marked suicidal thinking, multiple neurovegetative symptoms, and markedly impaired functioning, argue strongly for the use of medication. A chronic or multiepisode history argues for more prolonged treatment. Symptom severity should be gauged by either clinical interview or rating scales, since severity plays a role in treatment planning (Depression Guideline Panel, forthcoming). When there is historical, symptomatic, or physiologic evidence to suggest an underlying general medical disorder as the cause of the depression, physical examination and laboratory tests to detect the specific disorder(s) should be used as appropriate in the differential diagnosis. The presence of another medical condition does not exclude the depressive syndrome. In fact, it increases the probability that a depressive syndrome may be present. The depression is either present or absent, based on the patient's signs/symptoms. If the patient has a depression, the first steps in its treatment differ according to whether another general medical condition is present and thought to be causal, whether alcohol or substance abuse is present, and whether another nonmood psychiatric disorder is present and causal. Screening Instruments Patient Self-Report Questionnaires Easily administered self-report questionnaires can be used as a lowcost, but valuable, case-finding tool to help clinicians better detect currently depressed patients. Numerous scales are available for assessment of depression (Beckham and Leber, 1985; Marsella, Hirschfeld, and Katz, 1987). It is not uncommon for primary care practitioners to have patients complete self-report depression rating scales in the waiting room to elicit these symptoms. These self-reports are not diagnostic, but they are very sensitive to depressive symptoms. These self-report scales are also useful in detecting milder mood conditions. The four used most commonly in ambulatory medical care settings are the General Health Questionnaire (GHQ), which has one subscale for depression; the Center for Epidemiological StudiesDepression Scale (CES-D); the Beck Depression Inventory (BDI); and the Zung Self-Rating Depression Scale (ZSRDS) (Coulehan, Schulberg, and Block, 1989). Patient responses to these instruments cannot be used directly to formulate a diagnosis of depression; however, a high score on one of these instruments warrants a clinical interview based on DSM-III-R criteria. Some of these limitations have been addressed by newly developed measures—the Inventory to Diagnose Depression (Zimmerman, Coryell, Stangl, et al., 1987) or the Inventory for Depressive SymptomsSelf-Report (Rush, Giles, Schlesser, et al., 1986). Although initial results are promising, these instruments have not yet been applied extensively in primary care settings. All four self-report measures commonly used in primary care settings (GHQ, CES-D, BDI, and ZSRDS) help to identify potentially depressed patients with varying degrees of power exceeding chance. All have positive predictive values between two and four times the 6 to 8 percent base rate of major depression. That is, the false-positive rate for detecting major depression with self-reports may be as high as two- to threefold. They detect nearly every patient with major depressive disorder, but they are not very specific. They identify many patients who ultimately prove not to have a mood disorder. In essence, there are few false-negative results, but many (25 to 40 percent) false-positive results. Fifteen studies have rigorously evaluated the predictive value of selfreport questionnaires for depression in primary care populations by using the diagnosis from a structured psychiatric assessment as the “gold standard" against which the self-report formulation is compared (Coulehan, Schulberg, and Block, 1989). This body of research leads to the following recommendations for case finding with self-report measures: ■ Since the positive predictive value of self-report questionnaires relates to the prevalence of the disorder in the clinical population, depression scales are most appropriately and efficiently administered to those at higher risk for this disorder. This group includes patients with disabling chronic diseases; unexplained or ill-defined symptoms; sleep complaints; history of prior psychiatric illness; headaches, abdominal pain, or other pain complaints; or either a sad mood or reduced interest or pleasure. ■ Cutoff thresholds for each questionnaire must be established at levels specific to primary care populations. Since positive predictive value is linked to the disorder's prevalence, the threshold most appropriate to particular medical patient groups differs from that to be used with psychiatric or community cohorts. Several investigators have recommended that significantly higher cutoff scores be used with selfreport instruments in medical practices to reduce the proportion of falsepositives produced by cutoff scores established in community studies (Schulberg, Saul, McClelland, et al., 1985; Turner and Romano, 1984). If the practitioner is already highly attuned to and inquires regularly about depressive symptoms, the self-reports may add little to his or her practice. Since these questionnaires identify patients as "depressed" when they have only some symptoms, but not the disorder, the practitioner should not rely exclusively on them to make a diagnosis of depressive disorder. Clinician-Completed Rating Scales Several available rating scales are to be completed by the clinician: the Hamilton Rating Scale for Depression (HRS-D) (Hamilton, 1968), the Montgomery-Asberg Depression Rating Scale (MADRS) (Montgomery and Asberg, 1979), the Inventory for Depressive Symptomatology-Clinician Rated (IDS-C) (Rush, Giles, Schlesser, et al., 1986), the Bech-Rafaelsen Depression Scale (BRDS) (Bech, Kastrup, and Rafaelsen, 1986), and depression items of selected structured interviews such as the Present State Examination (PSE) (Wing, Birley, Cooper, et al., 1967) and the Schedule for Affective Disorders and Schizophrenia (SADS) (Endicott and Spitzer, 1978). These may be more sensitive to improvement in the course of treatment and may have slightly greater specificity than do self-reports in detecting depression. A systematic approach to the identification of depressive disorders can be derived from the information obtained on these questionnaires and scales: 1. Self-report questionnaires can be used to identify those unlikely to have major depressive disorder. No further questioning or evaluation need be performed with these patients. 2. The condition of those who have significant depressive symptoms based on a self-report should be further evaluated by clinical interview to determine whether the symptoms are of sufficient intensity, number, and duration to meet the criteria for major depressive disorder (or another mood disorder) according to DSM-III-R. 3. Some patients who meet the criteria for major depressive disorder, but have a very mild condition (not chronic, psychotic, significantly disabling, or suicidal), may either begin treatment or wait for a reevaluation of their condition in 1 to 2 weeks before starting specific treatment, since some 15 to 25 percent (or higher) of these patients respond to supportive care from the practitioner. Should the patient respond fully to supportive care, the practitioner is advised to see the patient again, as some patients' symptoms return. 4. Those whose major depressive symptomatology is persistent, disabling, or moderate to severe should be treated. Those with moderate to severe symptoms, in a prolonged depressive episode, or with recurrent episodes with poor interepisode recovery are less likely to respond to clinical management and reassurance alone, and treatment should not be delayed. |