Catatonia-like events after valproic acid with risperidone and sertraline

A patient with schizoaffective disorder developed signs of catatonia while on a regimen of valproic acid, sertraline, and risperidone. The catatonic features evolved for the first time after a single dose of valproate and were alleviated by lorazepam. The same catatonic signs recurred after a second dose of valproate and again remitted after lorazepam. Catatonia did not recur subsequent to discontinuing valproate, and the patient had tolerated the combination of valproate and risperidone in the past without developing catatonia. Although the catatonia in this case initially appears to be paradoxical, the phenomenon is actually consistent with current models of catatonia. A unique drug interaction may account for this phenomenon. Possible pharmacokinetic and pharmacodynamic explanations are discussed, including the relation of catatonia to increased activity of the medial globus pallidus and current models of catatonia.