Cycloid psychoses constitute an original classification originally proposed by Leonhard and comprising clinical pictures intermediate between schizophrenic psychoses and bipolar disorders. The exact situation of these disorders in psychiatric classifications has been the subject of debate, and their existence is still questioned. Only schizo-affective psychoses have been accepted as autonomous. Treatment of cycloid psychoses most often consists of neuroleptics but also mood regulators, particularly those having anti-epileptic effects Lastly, prognosis of these disorders usually is not as poor as that of schizophrenia and is marked by a cycloid course, with symptom-free periods between episodes.