Time Estimation Among Schizophrenics

Abstract

Studies of time estimation among schizophrenics have sometimes been difficult to integrate with one another because of differing methodologies and inconsistent definitions. The present study should increase clarity by employing several methods of time estimation within the same study and maintaining a consistent definition of overestimation and underestimation across tasks. 26 schizophrenic and 26 control subjects were given three types of time-estimation tasks. Longer interval Estimation involved judging, at different points in the interview/testing session, how much time had passed. Verbal Estimation required subjects to judge the length of brief intervals signalled by the examiner. Operative Estimation required subjects to indicate when a specified number of seconds had passed. Schizophrenic subjects were significantly more inaccurate than controls in the Verbal and Operative Estimation tasks. Moreover, with overestimation defined consistently as judging more time to have passed than actually has, both Verbal and Operative Estimation results indicated schizophrenics were significantly more likely to overestimate. These results indicate support for the suggestion that schizophrenics have a disturbed sense of time, with real (clock) time experienced as passing more slowly than is actually the case. Long Interval Estimation produced quite different results, but it was felt that the retrospective and unfocused nature of the time judgments in this task made it a less valid indicator of ability to estimate.

Temporal processing dysfunction in schizophrenia

“…Specifically, individuals diagnosed with schizophrenia have consistently been found to experience time as lengthened relative to objective time, which has been interpreted to reflect an increase in the speed of a hypothetical "internal clock" (Densen, 1977;Johnson & Petzel, 1971;Lhamon & Goldstone, 1956;Tracy et al, 1998;Tysk, 1983aTysk, , 1983bTysk, , 1990Wahl & Sieg, 1990). For instance, numerous behavioral studies have reported overestimations and underproductions of temporal durations ranging from several seconds to one minute in schizophrenia (Densen, 1977;Johnson & Petzel, 1971;Tysk, 1983aTysk, , 1983bTysk, , 1990Volz et al, 2001;Wahl & Sieg, 1980), which is consistent with patients' subjective reports of an elongated experience of time (Freedman, 1974).…”

“…Following this line of thinking, and given that schizophrenia is characterized by profound disturbances in perception, attention, and cognition, it is not surprising that schizophrenia has also been associated with systematic distortions of time (Densen, 1977;Johnson & Petzel, 1971;Tysk, 1983aTysk, , 1983bTysk, , 1990Volz et al, 2001;Wahl & Sieg, 1980). Specifically, individuals diagnosed with schizophrenia have consistently been found to experience time as lengthened relative to objective time, which has been interpreted to reflect an increase in the speed of a hypothetical "internal clock" (Densen, 1977;Johnson & Petzel, 1971;Lhamon & Goldstone, 1956;Tracy et al, 1998;Tysk, 1983aTysk, , 1983bTysk, , 1990Wahl & Sieg, 1990).…”

Perception and Estimation of Time

“…The most significant results seem to be as follows: schizophrenics overstimate brief durations, whether in estimation at various moments of an interview-testing session or in operational estimation. In this method the S was required to indicate when a specified number of seconds had passed (Wahl & Sieg 1980). This overestimation of brief durations must have been brought out by the well-known characteristic of chronic schizophrenics.…”

Duration judgements in patients with schizophrenia

“…Indeed, research on time estimation in schizophrenia has a long history (Clausen, 1950;Lhamon & Goldstone, 1956;Webster et al 1962;Lhamon et al 1965 ;Orme, 1966;Carlson & Feinberg, 1968), and there have been numerous reports of impaired temporal comprehension in these patients (Dilling & Rabin, 1967;Johnson & Peztel, 1971 ;Lhamon & Goldstone, 1973;Densen, 1977 ;Wahl & Sieg, 1980 ;Tysk, 1983aTysk, , b, 1984Tysk, , 1990Rammsayer, 1990;Tracy et al 1998; though see Webster et al 1962 ;Goldstone et al 1979 ;Crain et al 1975). Studies have indicated that schizophrenic patients are not simply less accurate in time estimation tasks, but show a particular kind of distortion in timing, in that they tend to overestimate time intervals (Tracy et al 1998 ;Tysk, 1983aTysk, , b, 1984Tysk, , 1990.…”