Pharmacopsychiatry 2000; 33(1): 38-41
DOI: 10.1055/s-2000-8452
Case Report
Georg Thieme Verlag Stuttgart ·New York

Posthallucinogen-Like Visual Illusions (Palinopsia) with Risperidone in a Patient without Previous Hallucinogen Exposure: Possible Relation to Serotonin 5HT2a Receptor Blockade

E. Lauterbach, A. Abdelhamid, J. B. Annandale
  • Department of Psychiatry and Behavioral Sciences, Department of Internal Medicine, Neurology Section Mercer University School of Medicine, Macon, GA, USA
Further Information

Publication History

Publication Date:
31 December 2000 (online)


Background: Previous reports document visual illusions resembling hallucinogen persisting perception disorder (HPPD) after risperidone treatment in patients with histories of previous LSD exposure. Methods: We report a case with visual disturbances resembling HPPD after each of three consecutive risperidone dose increases. Results: Contrasting with previous reports, our patient lacked any history of substance abuse, particularly hallucinogen exposure. She lacked neurologic or other contributory illnesses. Illusions generally remitted within 48 hours each time. Coadministration of trazodone and clonazepam may have contributed to these phenomena, although clonazepam has been used to treat this condition. She had been unusually sensitive to the side-effects of many psychotropics. Conclusions: This case is unique due to the absence of substance abuse. This and another report note heightened sensitivity to medication side-effects. Visual phenomena resembling HPPD evidently can occur with risperidone and, possibly, other atypical antipsychotics and certain antidepressants regardless of previous hallucinogen use. Several lines of evidence implicate reduced 5HT2a serotonin receptor stimulation rather than increased 5HT2c stimulation.


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M.D. Edward C. Lauterbach

Professor of Psychiatry and Internal Medicine (Neurology) Department of Psychiatry and Behavioral Sciences Mercer University School of Medicine

1550 College Street

Macon, GA 31207


Phone: (912) 301-5337