Dear Editor:
Topiramate has been used commonly as anticonvulsant and as mood stabilizer or augmentation agent in bipolar disorder, and in some cases for management of neuroleptic-induced weight gain.1,2 Common side effects include somnolence, nausea, anorexia, weight loss, psychomotor slowing, dizziness, and renal calculi.1 This letter reports a rare case of paranoid psychosis from topiramate.
Case report. A 34-year-old woman, married, with two children, presented to our outpatient clinic for psychiatric evaluation. The patient previously was diagnosed with bipolar disorder type II and currently was on valproic acid 1250mg/day and citalopram 20mg/day. The patient came to our outpatient clinic because her previous psychiatrist moved out of the area and the patient needed a new psychiatrist. The patient reported doing well on the current medications except that she had gained 50 pounds in the last year. Her current body mass index was 31. She reported that she started gaining weight around the same time she started taking valproic acid.
The patient was maintained on her previous medications at the same dosages, and topiramate was initiated at 25mg/nightly by the treatment team to help the patient lose weight. Three days after starting topiramate, the patient called the clinic complaining of severe paranoid symptoms. She reported that ever since she started taking topiramate, she had the feeling the whole world was after her. She also reported feeling paranoid toward her children and husband. She reported feeling as if everybody was conspiring to get rid of her, and she was scared to go to sleep. The patient denied ever having paranoid feelings in the past. The treatment team decided to discontinue the topiramate immediately. A week later, the patient reported the paranoid thoughts stopped within two days of discontinuing topiramate. The patient was reluctant to try other medications and expressed her desire to try other ways to lose weight (diet control, exercise). The patient continued on valproic acid and citalopram and was recommended for nutritional consultation.
Discussion. There are a few case reports3,4 that discuss the emergence of psychotic symptoms induced by topiramate. Though it is a very rare side effect, clinicians should be aware of this risk as it can easily be mistaken for decompensation of a patient's mental health state or the emergence of a new psychiatric symptom.
The mechanism underlying psychotic symptoms induced by topiramate is not clear, but a GABAergic hypothesis with inhibition of the substantia nigra and overactivity of ascending dopaminergic pathways has been proposed.4
With regards,
Tanvir Singh, MD
University of Toledo Medical Center, Toledo, Ohio
References
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