Treatment of acute mania with methylphenidate: therapeutic approach based on a new pathophysiological model.

The initial treatment for patients with acute mania represents a significant clinical challenge, given that treatments for mania symptom control usually take several days to start acting. Most treatments available for the manic phase of bipolar disorder are sedatives, to lower the hyperactivity and excitation that patients with mania present. However, recent observations indicate that these symptoms may be the result of a self-regulating mechanism consisting of an increase in excitation and activity to compensate a deficit in vigilance or arousal. What is involved is a physiopathological model that proposes the existence of a state of brain hypoactivation in mania and that can open new therapeutic approaches. The arousal regulation model has recently been proposed as a physiopathological mechanism that may be altered in affective disorders. The transition from the arousal state to that of sleep corresponds to different neurophysiological levels of vigilance, so various brain activity stages can be measured using electroencephalography (EEG). Regulating arousal levels implies an adaptive physiological mechanism that can adapt to an individual’s biological needs and to environmental circumstances. For example, in situations of danger the organism raises the arousal level to face the situation, while vigilance drops in rest periods. In addition, continued states of increased arousal are often linked with the tendency to withdraw from external stimulation; in contrast, tired states can be associated with hyperactive behaviour as a self-regulating attempt to maintain arousal level. Based on this model, some vulnerable individuals present alterations in the self-regulating physiological arousal mechanisms, so states of brain