Clinical features of latent inhibition in schizophrenia

Paradigms of Latent Inhibition (LI) are inter-species and derived from learning theories. They are considered as tools which allow the attentional processes to be studied. The absence of LI is interpreted as difficulty in discriminating relevant and irrelevant stimuli. Abolition of LI has been shown in acute schizophrenics. The objectives of our study were partly to validate an LI paradigm, based on a contingency detection between two stimuli, in healthy subjects, and partly to analyse LI in schizophrenics. The study included 105 subjects (65 patients and 40 controls). Patients fulfilled the DSM IV diagnosis of schizophrenia. 35 in the acute phase and 30 in the chronic phase. We observed a loss of LI for acute schizophrenics, and an enhancement of LI for chronic schizophrenics. The variations in LI are interpreted from the perspective of a disturbance in the attentional processes. The LI status in acute schizophrenics appears to correlate with the clinical criteria with a prognostic value (low intensity of the negative dimension, late age at the first hospitalization). Moreover, the enhancement of LI correlates with the negative dimension of schizophrenic disease. This correlation is found in acute and chronic schizophrenics. It suggests that the variations of LI may be an indicator of adaptive strategies to a cognitive dysfunction specific to schizophrenia.