Recognizing Mimics of Depression: The '8 Ds': This Mnemonic Helps Recall Conditions That May Make Medically Ill Patients Appear Depressed

Many psychiatric and medical illnesses as well as normal reactions to stressors have symptoms that overlap with those of depressive disorders, including outwardly sad or dysphoric appearance, irritability, apathy or amotivation, fatigue, difficulty making decisions, social withdrawal, and sleep disturbances. This cluster of symptoms forms a readily observable behavioral phenotype that clinicians may label as before considering a broader differential diagnosis. To better understand what other conditions belong in the differential diagnosis, we reviewed a sample of 100 consecutive medical/ surgical inpatients referred to our consultationliaison psychiatry practice for evaluation of Ultimately, only 29 of these patients received a diagnosis. Many of the other diagnoses given in our sample required attention during inpatient medical or surgical care because they were potentially life-threatening if left unaddressed--such as delirium--or they interfered with managing the primary medical or surgical condition for which the patient was hospitalized. Hurried or uncertain primary care clinicians frequently use depression as a catch-all term when requesting psychiatric consultation for patients who seem depressed. A wide range of conditions can mimic depression, and the art of psychosomatic psychiatry includes considering protean possibilities when assessing a patient. We identified 7 diagnoses that mimic major and developed our 8 D differential to help clinicians properly diagnose depressed patients who have something other than a depressive disorder. Although our sample consisted of hospitalized patients, these mimics of may be found among patients referred from other clinical settings for evaluation of possible depression. [ILLUSTRATION OMITTED] [ILLUSTRATION OMITTED] [ILLUSTRATION OMITTED] The perils of misdiagnosis Depression is common among patients hospitalized with medical or surgical conditions. DSM-IV-TR diagnostic criteria for a major depressive episode (MDE) include the presence of low mood and/or anhedonia, plus [greater than or equal to]4 other depressive symptoms for[greater than or equal to]2 weeks. (1) Growing evidence suggests that the relationship between and morbidity and mortality in medical illness is bidirectional, and nonpsychiatrists are becoming increasingly aware of major depression's serious impact on their patients' physical health. (2-5) Although improving nonpsychiatrists' recognition of in medically ill patients is laudable, it comes with a high falsepositive rate. In a study of primary care outpatients, Berardi et al found that 45% of patients labeled depressed did not meet ICD-10 criteria for major depression, but >25% of those patients were prescribed an antidepressant.6 In a large retrospective study, Boland et al found that approximately 40% of patients referred to an inpatient psychiatric consultation service for did not meet criteria for a depressive illness, and primary medical services often confused organic syndromes such as delirium and dementia with depression.' Similarly, Clarke et al found that 26% of medical and surgical inpatients referred to psychiatry with depression had another diagnosis commonly delirium that better accounted for their symptoms. (8) What is the harm in overdiagnosing depression? Missing a serious or lifethreatening diagnosis is a primary concern. For example, unrecognized delirium, which frequently was misdiagnosed as in the Berardi, (6) Boland (7) and Clarke (8) studies, is associated with myriad difficulties, including higher morbidity and mortality. (9) Substance use disorders, which also commonly masquerade as depression, frequently are comorbid with medical illness. Delays in appropriate treatment of withdrawal syndromes particularly of alcohol and sedative/hypnotic medications--are risk factors for increased mortality in these illnesses. …