August 23, 2005

Adjunctive Topiramate for Treatment Resistant Schizophrenia

A new study suggests that using the drug topiramate in addition to antipsychotic medication may be helpful for 10%-20% of those with treatment-resistant schizophrenia.

According to the researchers in the study less than 50% of those suffering from schizophrenia get a complete response to antipsychotics. Topiramate is a "glutamate antagonist" and is often used for those who are only receiving a portion of the benefits that are usually accrued by those taking antipsychotics.

The study's participants were 26 hospitalized patients suffering from treatment-resistant schizophrenia. Randomly, they were either given 300/mg a day of topiramate or just a placebo in addition to the antipsychotic that they were already taking. The antipsychotics that were being taken were: clozapine (Clozaril), olanzapine (Zyprexa), risperidone (Risperdal), or quetiapine (Seroquel).

18 of the 26 completed the full study and findings exemplified that topiramate was much better than the placebo at reducing depression and "feelings of guilt". This was shown by their scores on the positive and negative syndrome scale. Those taking topiramate had their scores reduced from 38.32 to 36.29, whereas those on placebo had scores that went from 36.19 to 36.96. Three of the patients on topiramate adjunctive therapy even had over a 20% reduction in their psychopathologic symptom scores.

"Despite these reductions in psychopathologic symptoms, topiramate therapy did not significantly improve positive or negative symptoms, the researchers report in the Journal of Clinical Psychiatry" (, 2005). The drugs side effects were relatively minimal and were tolerated by most of those taking topiramate in this study. Researchers added that based on the findings it seemed that topiramate may help those who are chronically ill and dealing with psychopathologic symptoms.

Original Source: Adjunctive topiramate shows treatment-resistant schizophrenia benefits. August 23, 2005.

This research article was published in J Clin Psychiatry 2005; 66: 1012–1015.


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