Takuma Inagawa1, Natsuki Ueda2,3, Kazuyuki Nakagome1, Tomiki Sumiyoshi4. 1. Department of Psychiatry, National Center Hospital, National Center of Neurology and Psychiatry, Tokyo, Japan. 2. Department of Clinical Epidemiology, Translational Medical Center, National Center of Neurology and Psychiatry, Tokyo, Japan. 3. NCNP Brain Physiology and Pathology, Tokyo Medical and Dental University, Tokyo, Japan. 4. Department of Preventive Intervention for Psychiatric Disorders, National Center of Neurology and Psychiatry, National Institute of Mental Health, Tokyo, Japan.
Abstract
AIMS: Dopamine (DA) hyperactivity causes overestimation of time, whereas DA hypoactivity produces its underestimation. DA activity also provides neurochemical substrates pertinent to several psychiatric conditions, such as schizophrenia and Tourette's syndrome. The overestimation of time sometimes exists in patients with Tourette's syndrome, but no reports have addressed time perception in relation to antipsychotic medications which typically act as DA receptor antagonists. We herein report a case of Tourette's syndrome, in which time estimation was differentially affected by risperidone (a DA antagonist) and aripiprazole (a DA partial agonist). CASE: A 27-year-old man who suffered from verbal and motor tics was treated with risperidone. His tic symptoms disappeared; however, he began to experience a strange feeling that "time is going too fast." For example, "people walk more quickly compared to a normal pace." These complaints were thought to represent underestimation of time. Then, risperidone was switched to oral aripiprazole to optimize DA transmissions, which resulted in the amelioration of these subjective feelings. CONCLUSION: Our observations indicate that the underestimation of time may occur in patients with Tourette's syndrome who receive antipsychotic drugs with high DA D2 receptor blocking potency. This may support the concept that the estimation of time is influenced by DA activity.
AIMS: Dopamine (DA) hyperactivity causes overestimation of time, whereas DA hypoactivity produces its underestimation. DA activity also provides neurochemical substrates pertinent to several psychiatric conditions, such as schizophrenia and Tourette's syndrome. The overestimation of time sometimes exists in patients with Tourette's syndrome, but no reports have addressed time perception in relation to antipsychotic medications which typically act as DA receptor antagonists. We herein report a case of Tourette's syndrome, in which time estimation was differentially affected by risperidone (a DA antagonist) and aripiprazole (a DA partial agonist). CASE: A 27-year-old man who suffered from verbal and motor tics was treated with risperidone. His tic symptoms disappeared; however, he began to experience a strange feeling that "time is going too fast." For example, "people walk more quickly compared to a normal pace." These complaints were thought to represent underestimation of time. Then, risperidone was switched to oral aripiprazole to optimize DA transmissions, which resulted in the amelioration of these subjective feelings. CONCLUSION: Our observations indicate that the underestimation of time may occur in patients with Tourette's syndrome who receive antipsychotic drugs with high DA D2 receptor blocking potency. This may support the concept that the estimation of time is influenced by DA activity.