Disordered time perception has been reported in schizophrenia. We investigated time perception dysfunction and its neuropsychological correlates in patients with schizophrenia. Thirty-eight patients and thirty-eight age and sex matched healthy volunteers were compared in an auditory temporal bisection paradigm using two interval ranges (a 400/800ms condition and a 1000/2000ms condition). In the temporal bisection, subjects were required to categorise a probe duration as short or long, based upon the similarity with two reference durations. All subjects also completed a battery of neuropsychological tests measuring sustained attention, shortand long-term memory and executive function. In the 400/800ms condition, patients judged durations significantly shorter than did control subjects. Patients also exhibited decreased temporal sensitivity in both conditions. We found in both groups a negative association between temporal sensitivity and sustained attention for the 400/800ms condition, and between temporal sensitivity and long-term memory for the 1000/200ms condition. In patients, short-term memory performance was negatively associated with duration judgement in both conditions, while executive dysfunction was correlated to a general performance deficit in the 400/800ms condition. These findings suggest the possibility that time perception abnormalities in schizophrenia are part of neuropsychological dysfunction and are likely to adversely impact upon activity of daily living.

People with schizophrenia have been categorised into three groups: those with full insight (aware, correct attributers); those aware of being unwell, but who misattributed their symptoms (aware, incorrect attributers); and those unaware of being ill (unaware). Cluster analysis of 'awareness of illness'and 'relabelling of symptoms'scores on the Schedule for the Assessment of Insight confirmed three distinct subgroups. The unaware group were impaired on executive and memory tests, whereas those in the aware, misattributing group were cognitively intact. Findings support an association between unawareness of illness and executive dysfunction, and highlight the separation of symptom misattribution from unawareness of illness.

Our findings suggest that phonological speech production is markedly disrupted by schizophrenia. Further, this phonological abnormality is distinct from disorganisation syndrome.

The Analogies Understanding Test (AUT) was developed as a brief cognitive screening task of executive problem solving. A few of the test items at the beginning are "facilitated" as a means of engaging patients. Individuals with schizophrenia and mild Alzheimer's Disease (AD) made significantly less correct responses than their control groups. The schizophrenia patients, but not AD patients, made significantly more perseverations than controls on the AUT. As expected, AUT performance in schizophrenia patients correlated with the Wisconsin Card Sorting test measures. Preliminary findings suggest that the AUT test may be useful as a measure of executive dysfunction in neuropsychiatric patients.