Involuntary emotional expression disorder - new/old disease in psychiatry and neurology.

Involuntary emotional expression disorder (IEED) is underrecognized by clinicians, misdiagnosed as depression or bipolar disorder and undertreated, because clinicians are unfamiliar with the disorder. An important clinical consideration for IEED is that of distinguishing mood from affect. IEED describes a syndrome of relatively stereotypical episodes of uncontrollable crying and/or laughing, resulting from lesions of multiple types, in multiple brain regions, without an apparent stimulus to trigger such responses. This syndrome is common among a number of neurological diseases like patients with a stroke or traumatic brain injury (TBI), patients with amyotrophic lateral sclerosis (ALS), multiple sclerosis (MS), as well as dementias such as Alzheimer;s disease (AD), and motor disorders such as Parkinson;s disease (PD). The neuropathological cause and neurochemistry of the disorder remains unclear. There is general agreement that IEED is the result of an injury to the neurological pathways that control the expression of emotions. Adequate treatment can reduce the frequency and improve the quality of life of patients and caregivers.