Pseudobulbar affect: the spectrum of clinical presentations, etiologies and treatments.

Pseudobulbar affect (PBA) consists of uncontrollable outbursts of laughter or crying inappropriate to the patient's external circumstances and incongruent with the patient's internal emotional state. Recent data suggest disruption of cortico-pontine-cerebellar circuits, reducing the threshold for motor expression of emotion. Disruption of the microcircuitry of the cerebellum itself may likewise impair its ability to act as a gate-control for emotional expression. Current evidence also suggests that serotonergic and glutamatergic neurotransmission play key roles. Although antidepressants have shown benefit, the supportive clinical data have often derived from small numbers of patients and unvalidated measures of PBA severity. Dextromethorphan/quinidine, the first FDA-approved PBA medication, is a novel therapy with antiglutamatergic actions. As life expectancy lengthens and the neurologic settings of PBA become more common, the need for treatment can be expected to increase.