Time discrimination deficits in schizophrenia patients with first-rank (passivity) symptoms

Schizophrenia patients with first-rank (passivity) symptoms (FRS) report a loss of clear boundaries between the self and others and that their thoughts and actions are controlled by external forces. One of the more widely accepted explanatory models of FRS suggests a dysfunction in the 'forward model' system, whose role consists in predicting the sensory consequences of actions [Frith, C., 2006. The neural basis of hallucinations and delusions. Comptes Rendus Biologies 328, 169-175.]. There has been recent interest in the importance of timing precision underlying both the functioning of the forward model, and in processes contributing to the mechanisms of self-recognition [Haggard, P., Martin, F., Taylor-Clarke, M., Jeannerod, M., Franck, N., 2003. Awareness of action in schizophrenia. Neuroreport 14, 1081-1085.]. In the current study, we examined whether schizophrenia patients with FRS have a time perception impairment, using an auditory discrimination task requiring judgements of temporal intervals. Thirty-five schizophrenia patients (15 with, and 20 without, FRS), and 16 non-clinical controls completed the task. The results showed that patients with FRS experienced time differently by underestimating the duration of time intervals. Given the role of timing in shaping sensory awareness and in the formation of causal mental associations, a breakdown in timing mechanisms may affect the processes relating to the perceived control of actions and mental events, leading to disturbances of self-recognition in FRS. (C) 2008 Elsevier Ireland Ltd. All rights reserved.