This study examines psychomotor inhibition, sustained attention, and inhibitory attentional control in adolescents (ages 12-18 years) with a nonmanic mood disorder and with a first-degree relative with bipolar I disorder (MD, N = 20) and demographically matched healthy children of parents without any psychiatric disorder (HC, N = 13). MD participants showed abnormal performance in stop signal reaction time and latency (d = 1.28 and 1.64, respectively), sustained attention response bias (d = 0.75), and color naming speed (d = 0.88). The results indicate that MD participants exhibit psychomotor disinhibition, marginal cognitive slowing and cautious response biases, but no formal deficits in sustained or selective attention.