Laughter is not always a pleasant experience and is associated with several negative phenomena. Excessive laughter can lead to   cataplexy , and unpleasant laughter spells, excessive elation, and fits of laughter can all be considered negative aspects of laughter. Unpleasant laughter spells, or "sham mirth", usually occur in people who have a neurological condition, including patients with   pseudobulbar palsy ,   multiple sclerosis and   Parkinson's disease . These patients appear to be laughing out of amusement but report that they are feeling undesirable sensations "at the time of the punch line". Excessive elation is a common symptom associated with  bipolar disorder  psychoses and  mania / hypomania . Those with schizophrenic psychoses seem to experience the opposite—they do not understand humor or get any joy out of it. A fit describes an abnormal time when one cannot control the laughter or one's body, sometimes leading to seizures or a b...