Typical - dizziness, agitation, sleepiness, stiff jaw, weight gain and itchy skin. Long-term use can cause tardive dyskinesia (dopamine sensitivity manifesting as involuntary facial movements e.g. grimacing, blinking and lip-smacking. Most serious is neuroleptic malignant syndrome (NMS) because of drug blocking dopamine receptors in hypothalamus (regulates a number of body functions). Causes high temperature, delirium and coma (can be fatal).