The following is a guest post from Sven Thönes at Johannes Gutenberg-Universität Mainz, Germany.
Over the last decades, numerous studies have reported that the perception of time and the basic processing of temporal information is distorted in patients suffering from schizophrenia. The investigation of timing in schizophrenia is of particular interest because the notion of mistimed information transfer by Andreasen, et al. (1999), which is one of the most popular theories on the cognitive impairments and clinical outcomes in schizophrenia, assumes that distorted temporal processing may underlie the patients’ symptoms.
In a recent meta-analytical review published in Clinical Psychology Review, Sven Thoenes (Leibniz Research Centre for Working Environment and Human Factors) and Daniel Oberfeld (Johannes Gutenberg-University Mainz) reevaluated the data from 957 patients with schizophrenia and 1060 healthy control participants, provided by 68 studies on timing in schizophrenia from the past 65 years. The original studies applied a large variety of different temporal tasks, such as time estimation, production, reproduction, and duration discrimination, as well as the detection of temporal gaps and judgments of temporal order or simultaneity. Importantly, the reported behavioral measures represented different aspects of temporal performance, indexing between-group differences either in accuracy (i.e., signed deviation of the duration judgments from the veridical value) or precision (i.e., variability of the judgments or sensitivity in a discrimination task).
In their analyses, Thoenes and Oberfeld differentiated between different duration ranges and different temporal tasks representing either time perception (judgments of time intervals) or basic temporal processing (e.g., judgments of temporal order) as well as between effects of schizophrenia on accuracy and precision.
Interestingly, independent of the specific temporal tasks and interval durations used, the results clearly demonstrate that both time perception and basic temporal processing are less precise (more variable) in patients with schizophrenia (Hedges’ g > 1.00), whereas effects of schizophrenia on the accuracy of time perception are rather small and task-dependent. These results are in accordance with the theoretical assumption of mistimed information transfer and the notion of a more variable internal clock in patients with schizophrenia, but not with a strong effect of schizophrenia on clock speed.
The review suggests that future research needs to investigate to what degree the impairment of temporal precision may be due to clock-unspecific processes, such as general cognitive deficiencies in schizophrenia. Moreover, research should aim at combining established experimental and phenomenological approaches in order to gain a broader understanding of the specific temporal distortions in schizophrenia.
While research on time perception and temporal processing may be interesting as such, the recent meta-analysis shows that it may also be supportive for the generation and testing of theories in adjacent (cognitive) domains, such as clinical psychology and neuropsychology.
Thönes, S. & Oberfeld, D. (2017). Meta-analysis of time perception and temporal processing in schizophrenia: Differential effects on precision and accuracy. Clinical Psychology Review, 54, 44-64. http://dx.doi.org/10.1016/j.cpr.2017.03.007
Andreasen, N. C., Nopoulos, P., O’Leary, D. S., Miller, D. D., Wassink, T., & Flaum, L. (1999). Defining the phenotype of schizophrenia: Cognitive dysmetria and its neural mechanisms. Biological Psychiatry, 46, 908-20.