Schizophrenia, Paranoia, and Delusional Disorders

Psychosis, a serious mental illness characterized by problems with interpreting reality and associated with delusions or hallucinations, occurs in a variety of conditions among older adults, including “primary” syndromes (e.g., schizophrenia, delusional disorder) and “secondary” syndromes (e.g., psychosis of Alzheimer's disease). The prototypical example of a chronic primary psychotic disorder is schizophrenia. The great majority of descriptive and treatment-related research about schizophrenia has been conducted among younger patients. However, the absolute number of older adults with severe psychiatric illnesses, including schizophrenia, will increase dramatically as the baby boom population ages. Available data suggest that older persons with schizophrenia have differing symptom presentations, distinct treatment needs, and some surprising advantages over their younger counterparts.

Epidemiological studies provide an estimated prevalence of schizophrenia of 0.5% to 1% of the population among community-dwelling adults. Some surveys, including the Epidemiologic Catchment Area Study, indicate that the prevalence of schizophrenia declines with age, although these studies did not use age-related diagnostic criteria. The prevalence of psychotic symptoms is approximately 4% to 10% among older adults, with dementia accounting for a majority of these individuals. The ratio of women to men with schizophrenia during late life is roughly 3 to 2. In contrast to the stereotypical notion that older adults with schizophrenia typically reside in long-stay locked psychiatric facilities, it is estimated that 85% reside in the community. Those who do reside in institutions are typically placed in nursing homes. A majority of older persons with schizophrenia have few economic or social resources available to them.

In terms of its symptoms, schizophrenia is a heterogeneous syndrome that consists of a group of related illnesses and presentations. The hallmark symptoms of schizophrenia are positive symptoms [Page 504](e.g., delusions and hallucinations, disorganized thoughts and behavior), negative symptoms (e.g., emotional flattening, reduced motivation, anhedonia, poverty of speech, social withdrawal), and cognitive deficits (e.g., impairment of learning and executive functioning). To meet the criteria for a diagnosis of schizophrenia according to theDiagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV), symptoms must be present for at least 1 month, causing significant impairment in occupational or social functioning. Continuous signs of this disturbance, which may include prodromal or residual symptoms, must be present for 6 months. Available data indicate that the positive symptoms appear to become less severe with age among both community-dwelling and institutionalized patients. The negative symptoms do not appear to change significantly in severity with age.

People who experience delusions that are not bizarre, without accompanying prominent auditory or visual hallucinations and without overall personality deterioration, are classified as havingdelusional disorder. Delusional disorder is somewhat less common than schizophrenia and has received little study. Common delusions among elderly people include those of being spied on or followed, suspecting infidelity of the spouse, and having a physical disease (e.g., tumor) without evidence. Depression and anxiety are frequent among older adults with schizophrenia, and each contributes significantly to reduced quality of life. Schizoaffective disorder encompasses persons who have a major depressive or manic episode superimposed on symptoms of schizophrenia but who experience schizophrenic symptoms in the absence of mood problems for at least 2 weeks. As with delusional disorder, little is known about schizoaffective disorder in elderly people.

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