Abstract--While emotional outcome is a critical factor influencing early evolution and late prognosis after stroke, few relevant studies have been performed on this subject. However, mood changes, modified judgment, and emotional reactions may also dramatically alter recruitment into clinical trials; for instance, up to one third of patients with acute stroke may have altered time perception, inappropriate self-evaluation of their condition, and attentional or memory dysfunction, with a subsequent increase in referral-to-hospital delays. In addition, the value of the "informed" consenting process may be questionable in the setting of urgent randomization into an acute stroke clinical trial. Data from ongoing studies suggest that behavior and emotional reactions in acute stroke patients may be classified into a few broad categories, with considerable overlap. Correlations between mood changes and the type, location, and severity of stroke may provide useful information for improving patient management, including the prediction of functional evolution and late prognosis. While depressive reactions have been widely studied in the recovery-rehabilitation phase after stroke, significant depression is uncommon shortly after stroke. On the other hand, related, though different, emotional behavioral changes may be more frequent; these have often been confused with depression and include catastrophic reaction, emotionalism, and athymhormia. Late depression is the most common mood alteration during the first year after stroke and has specific characteristics that differentiate it from classic endogenous and reactive depression, thus emphasizing the critical role of brain damage in the pathogenesis of poststroke depression. Early recognition and management of mood disorders after stroke are critical for the functional improvement of individual patients. However, little is known about specific indications for different antidepressant drugs in poststroke depression and related disorders. Ongoing research has identified a "new" emotional-behavioral disorder, poststroke fatigue, which is clearly distinct from depression in most instances. It is especially disabling and frustrating in that it typically involves patients with total or near-total neurological recovery, who should have been able to go back to their previous activities but who become severely disabled because of early and persisting exhaustion. Preliminary neuropsychological and MR and PET imaging studies suggest that disruption of subtle mechanisms underlying attention, in the absence of significant cognitive and mood alterations, may be responsible. Research projects are now being launched to better delineate poststroke fatigue and its management.