Am J Psychiatry 154:2, February 1997 FORMAL THOUGHT DISORDER HARVEY, LOMBARDI, LEIBMAN, ET AL. Age-Related Differences in Formal Thought Disorder in Chronically Hospitalized Schizophrenic Patients: A Cross-Sectional Study Across N ine Decades Philip D. Harvey, Ph.D., Janel Lombardi, B.A., Martin Leibman, Ph.D., Michael Parrella, Ph.D., Leonard White, Ph.D., Peter Powchik, M.D., Richard C. Mohs, Ph.D., Michael Davidson, M.D., and Kenneth L. Davis, M.D. O bjective: This study used a cross-sectional design to examine the frequency of occurrence and severity of 10 different signs of thought disorder in schizophrenic patients across the lifespan. Method: Schizophrenic patients, who ranged in age from 19 to 96 years (N=392), were examined with the Scale for Assessment of Thought, Language, and Communication. The cognitive functioning of the geriatric patients (patients over the age of 64, N=120) was also assessed. Results: Poverty of speech was more common and more severe in geriatric patients, while four different signs of thought disorder that reflect disconnected speech were less common and less severe in geriatric patients. Analysis of covariance found that the lower severity of disconnection thought disorders in the older patients was not attributable to dif- ferences in the amount of speech produced. Conclusions: Aspects of disconnected speech were less severe in older patients, while the severity and frequency of poverty of speech were greater. These findings suggest that the two previously identified separate dimensions of communica- tion disorder in schizophrenia vary differently with age and possibly in their cognitive and biological underpinnings. (Am J Psychiatry 1997; 154:205–210) F ormal thought disorder is one of the most common symptoms in schizophrenia (1) and one of the most disabling. Severe impairments in communication char- acterize patients who are particularly unable to care for themselves and who have long periods of psychiatric care (2). Although formal thought disorder is now known to be present in other disorders, especially psy- chotic affective disorders (3–5), it is present in schizo- phrenia throughout the illness, including during peri- ods of relative remission of other psychotic symptoms. For instance, schizophrenic patients who have only re- sidual symptoms manifest continued impairments in communication, including deficient verbal productivity (6) and impaired connectedness of speech (7). These two dimensions of communication impairment, im- paired connectedness (“positive thought disorder” or “disconnection”) and reduced verbal output (“poverty of speech” or “alogia”), have been found in several dif- ferent studies of schizophrenic patients, including stud- ies that used exploratory and confirmatory factor analysis (8–13). While exploratory studies often have found three dimensions of communication disorder (8, 9), a confirmatory factor analytic study found that a two-dimensional model—verbal productivity and dis- connection—is most parsimonious (10). When these findings are extrapolated to broader studies of the or- ganizational structure of schizophrenic symptoms, re- duced verbal productivity and greater tendencies to- ward disconnection in speech correlate with symptom factors referred to as “negative symptoms” and “disor- ganization,” respectively (11–13). In the most recent of these studies (11), of all thought disorders examined, only the severity of derailment was correlated signifi- cantly with the severity of positive symptoms, including delusions and hallucinations. Regardless of its factor structure, formal thought dis- order has not been studied much across the lifespan of schizophrenic patients. Since formal thought disorder is apparently quite stable over time and clinical state in younger schizophrenic patients, aging-related changes could be expected to be minimal. Other evidence sug- Received Oct. 27, 1995; revisions received March 11 and Aug. 28, 1996; accepted Sept. 10, 1996. From the Department of Psychiatry, Mount Sinai School of Medicine. Address reprint requests to Dr. Harvey, Department of Psychiatry, Box 1229, Mount Sinai School of Medicine, New York, NY 10029. Supported by NIMH grant MH-46436 to Dr. Davidson and a Schizophrenia Biological Research Center grant from the Department of Veterans Affairs to Dr. Davis. The authors thank the following staff members who contributed to this study: Janice McCrystal, Stephanie Bowler, Rita Ohsiek, Susan Frick, and Cynthia Blum. Am J Psychiatry 154:2, February 1997 205