A common perception, based on relatively few published studies, is that most psychiatric disorders other than depression occur much less frequently among the elderly. Community samples, however, suggest that many older adults who experience clinically significant pathologies are overlooked or misdiagnosed, according to Dilip V. Jeste, M.D., and colleagues.
This discrepancy points out the need to develop age-appropriate diagnostic criteria that can assess elderly psychiatric patients, according to Dr. Jeste of the department of psychology at the University of California, San Diego, and associates (Biol. Psychiatry 2005;58:265–71).
Five potential causes of diagnostic confusion in the elderly were detailed:
▸ True age-related differences, in which symptoms of the disorder vary according to age. In such cases, application of DSM-IV criteria sets based on the disorder at a younger age results in under-, over-, or misdiagnosis in the elderly.
▸ Physical and psychiatric comorbidities, which tend to occur more frequently in the elderly, including general medical conditions such as congestive heart failure or cognitive deficiencies such as dementia.
▸ Underreporting of symptoms, which occurs more frequently in the elderly, biasing both epidemiologic and clinical-based studies toward underdiagnosis.
▸ Variation through time of onset, such as in major depression, which can show different symptoms in late, compared with early onset, the investigators said.
▸ Subthreshold presentations, in which older patients might experience clinically significant symptoms that fall below standard DSM-IV criteria sets. “For example 'minor generalized anxiety disorder' might have a different significance and outcome in elderly than in younger adults,” Dr. Jeste and associates reported.
Several categories of disorder can be subject to these various difficulties in diagnosis. For example, schizophrenia, though typically of early onset, also occurs in a sizeable minority of patients in middle or old age, and is often misdiagnosed as due to “organic” factors. According to the literature, 13% of all schizophrenia had onset between the ages of 41 and 50 years, 7% in patients aged 51–60 years, and 3% after age 60, they reported. Distinctiveness of symptoms in the “very late onset” indicates the illness may belong in a different category.
Anxiety disorders may be particularly difficult to pin down, according to the authors. For example, new-onset agoraphobic disorder would be less obvious, and thus underdiagnosed, in elderly patients who are less mobile and leave their houses less frequently.
Further research is needed to clarify the classification and incidence of late-life psychiatric disorders. “Most of the gaps in the current knowledge outlined … can be filled by systematic research and better attention to the potential presence of these disorders in elderly patients,” Dr. Jeste and associates said.