BACKGROUND: Attentional disturbances in Bipolar I Disorder (BID) have been increasingly reported but the majority of studies have not identified a model emphasizing component operations involved in attentional processes. In this study we sought to assess elementary attentional operations using the Posner paradigm for COVERT ORIENTING of visuospatial attention, with and without cues, to dissect levels of attentional impairment.METHODS: The study was carried out with 11 fully remitted BID single manic episode patients and 11 age-matched normal control subjects. The Hamilton Depression Rating Scale (HDRS), Young Mania Rating Scale (YMRS) and COVERT ORIENTING of Visuospatial Attention Task (COVAT) were administered. Reaction Times (RT) on the Posner task were examined with a multivariate approach by an Analysis of Variance (ANOVA) for repeated measures with Group as the between-subject factor and Stimulus Onset Asynchrony (SOA), Cue, and Visual Field as the within subject factors. RESULTS: The main effects involved Group, Cue, and SOA as well as interactions of Cue by SOA and SOA by Group. There was neither detectable effect of visual field, nor interactions involving visual field. The Group by Cue did not show a main effect. There was no abnormality in the COVERT ORIENTING in patients (i.e., Group by Cue by SOA by FIELD). RTs in the valid cues were significantly faster than the RTs in the invalid cues in the both groups. Only SOA had a main effect on the reaction time differences between invalid and valid cues.CONCLUSIONS: The main finding is that BID patients are generally slower compared to controls; however, the slowing is most pronounced at short SOA, suggesting that they are slower to initiate information processing following the cue. Interestingly, BID patients still show a cueing effects (valid RTs < invalid RTs) at short SOAs, suggesting that the RT deficit does not have any relationship with ORIENTING attention, but rather is a deficit in general arousal.