“One minute I’d be sobbing, crying hysterically, and the next minute I’d be laughing.

Cataplexy is a sudden and transient episode of loss of muscle tone, often triggered by emotions . . . The exact cause of cataplexy is unknown, but the condition is strongly linked to experiencing intense emotions and reduced levels of the neurochemical hypocretin.

Orexin, also called hypocretin, is a neurotransmitter that regulates arousal, wakefulness, and appetite. The most common form of narcolepsy, in which the sufferer briefly loses muscle tone (cataplexy), is caused by a lack of orexin in the brain due to destruction of the cells that produce it.

Pseudobulbar affect (PBA), emotional lability, labile affect or emotional incontinence refers to a neurologic disorder characterized by involuntary crying or uncontrollable episodes of crying and/or laughing, or other emotional displays.[1] PBA occurs secondary to neurologic disease or brain injury. Patients may find themselves crying uncontrollably at something that is only moderately sad, being unable to stop themselves for several minutes. Episodes may also be mood-incongruent: a patient might laugh uncontrollably when angry or frustrated, for example.