The dichotic listening (DL) task was developed originally to examine bottom-up or "automatic" information processing. More recently, however, it has been used as a tool in the study of top-down or "controlled" information processing. This has been done by including forced-choice conditions, wherein the examinee is required to focus attention on one or the other ear. It has been widely utilized with patients with schizophrenia, who exhibit rather severe deficits in managing their attention, but not with other patient groups, such as patients with bipolar disorder. In the present study, we examined potential performance similarities in the DL listening task. In total, the sample consisted of 38 patients with schizophrenia, 20 patients with psychotic bipolar disorder and 35 healthy individuals, who performed a DL task with verbal stimuli once at the beginning of their hospitalization and again on the last day before discharge. Our findings indicated that both patient groups showed similarly diminished performance when compared to healthy participants at both times of administration. Symptom improvement between the two evaluations did not significantly influence performance in the DL task. In conclusion, impaired automated and controlled information processing appears to be a common deficit in both schizophrenia and bipolar disorder.