Akathisia, or acathisia, is a synrome characterized by unpleasant sensations of "inner" restlessness that manifests itself with an inability to sit still or remain motionless, hence its origin in Ancient Greek α (a), [without, not] + κάθισις (káthisis), [sitting]. Its most common cause is as a side effect of medications, mainly neuroleptic antipsychotics especially the phenothiazines (such as perphenazine and chlorpromazine), thioxanthenes (such as flupenthixol and zuclopenthixol) and butyrophenones (such as haloperidol (Haldol)), piperazines (such as ziprasidone), and rarely, antidepressants. Akathisia can also, to a lesser extent, be caused by Parkinson's disease and related syndromes. But all neuroleptic antipsychotic psychotropic drugs cause Parkinsonian like symptoms due to blockage of dopamine receptors in the nigrostriatal pathway of the brain.