A three-year prospective study of spontaneous eye-blink rate in first-episode schizophrenia: relationship with relapse and neurocognitive function.

OBJECTIVE: To examine the spontaneous blink rate over a 3-year period and its clinical and cognitive correlates among patients with first-episode schizophrenia. METHODS: This study prospectively followed 93 patients with first-episode schizophrenia, schizophreniform and schizoaffective disorders for 3 years. Patients were longitudinally assessed for blink rate, their positive and negative symptoms, and a range of cognitive features including verbal fluency, verbal memory, visual memory, and the Wisconsin Card Sorting Test performance. RESULTS. When compared with a matched control group, there was a significantly higher blink rate at their 3-year follow-up but not at initial presentation. The increase in blink rate over time correlated positively with the number of relapses. It also correlated with logical memory, verbal fluency, categories completed, and perseverative errors in the Wisconsin Card Sorting Test. The increased blink rate also correlated with pre-morbid schizoid and schizotypal traits. All these correlations were statistically significant. CONCLUSION: The change in the blink rate over time may reflect underlying involvement of the dopaminergic system in mediating relapse and cognitive functions.