It's nothing to laugh about: understanding disorders of emotional expression.

Sudden outbursts of laughing, crying, or other emotional expression without an apparent triggering stimulus have been recorded in the literature for decades. Confusing nomenclature and a paucity of clinical research, however, have had clinicians wondering whether this syndrome may be both under-recognized and undertreated. Treatment options, including antidepressants, levodopa, and dextromethorphan/quinidine, may show promise in ameliorating symptoms for patients plagued with disorders of emotional expression.