Objective:Acetylcholinestrase inhibitors(AchEIs) are developed for cognitive enhancement and they also have effectiveness in behavioral and psychiatric symptoms of dementia. We experienced 1 case of psychotic symptoms recurred by AchEIs which had been well controlled by risperidone.
Case:A 83-year-old female patient lived in an asylum for the old. She was presented with 4-year history of cognitive impairment and 6-month history of psychotic symptoms (delusion, verbal aggression and constant demanding). She had a MMSE score of 19/30 with a college education. She had a medical history of hypertension. After a complete dementia workup, a diagnosis of Alzheimer's disease was made, and she was started on 1.5mg of risperidone a day for psychotic symptoms. After this therapy, her psychotic symptoms improved markedly. Four weeks later, we reduced risperidone 1mg and tried 3mg of rivastigmine for cognitive dysfunction. Three weeks later, her delusional ideations and verbal outbursts were recurred so we increased risperidone 1.5mg. Two weeks later, her psychotic symptoms did not improve, so we discontinued rivastigmine and increase risperidone up to 2mg. After 1 month, her psychotic symptoms improved but she showed incontinence of stool, so we tried 5mg of donepezil for the cognitive dysfunction. Two weeks later, her cognitive function improved and did not show incontinence of stool, but her delusional ideations and verbal outbursts appeared again. After we discontinued donepezil, she became quiet and did not show psychotic symptoms but her cognitive function decreased again. After 6 months, when we followed up, she was bed-ridden due to osteoarthritis and admitted to Geriatric Welfare Hospital. She was prescribed seroquel 50mg and Aricept 10mg, and she did not show psychotic symptoms.
Discussion:The mechanism of the recurrence of psychotic symptoms by AchEIs are unknown. According to the hypothesis that the increase of dopamine(DA) receptor stimulation in nucleus accumbens(NAC) decreases the GABAnergic output to the basal forebrain, thereby it causes disinhibition of the cortical acetycholine(Ach). In this case, the decrease in NAC DA receptor stimulation by antipsychotics increase the GABAnergic output, thereby it causes the inhibition of cortical Ach efflux, and finally it results in antipsychotic effects and cognitive decline. AchEIs, acts on upregulated postsynaptic Ach receptor, produce psychotic symptom and improve cognitive function. Although the acetylcholinestrase inhibitors are cognitive enhancer and they also have effectiveness in behavioral and psychiatric symptoms of dementia, they may reproduce delusions and angry outbursts in a certain stage of Alzheimer dementia.
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