Pathological Crying, Pathological Laughter
Pathological laughter and pathological crying (PLC), or forced laughter and crying, have been defined as reflecting an incongruence of mood (subjective feeling) and expression or affect ("objective", observed), such that patients laugh involuntarily though not happy, or cry though not sad. There may be a sense that the patient is struggling against these displays of emotion, in contrast to the situation in other forms of emotional lability where there is said to be congruence of mood and affect, although sudden fluctuations and exaggerated emotional expression are common to both, suggesting a degree of overlap.
PLC are ascribed to a loss (release) of the normal inhibition of the motor component of facial expression (i.e., cortical-subcortical disinhibition). PLC may occur in the context of a pseudobulbar palsy ("pseudobulbar affect") but not invariably so.
PLC has been reported in:
Multiple sclerosis: crying > laughing; related to intellectual impairment (more extensive brain involvement, but not brainstem)
Stroke: PLC may be the harbinger of brainstem stroke or a feature of anterior choroidal artery territory infarctions; rarely a feature of TIAs
Motor neurone disease Head injury
Suggested treatments for PLC include: Amitriptyline
Serotonin reuptake inhibitors: fluoxetine, citalopram.
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Larner AJ. Crying spells as symptoms of a transient ischemic attack.
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Wild B, Rodden FA, Grodd W, Ruch W. Neural correlates of laughter and humor. Brain 2003; 126: 2121-2138