Child psychiatrists and neurologists in Utrecht, The Netherlands report case histories of 2 girls, ages 4 and 12 years, with a history of epilepsy who developed hallucinations after withdrawal of valproic acid (VPA). The 4-year-old woke up at night and complained of seeing and hearing snakes in her bed, and the 12-year-old heard voices and saw nonexisting persons. When VPA was restarted the hallucinations rapidly disappeared. The hallucinations were explained by enhancement of dopaminergic neurotransmission elicited by a decrease of GABA or rebound of glutaminergic activity after rapid withdrawal of VPA. A possible role of VPA in controlling a predisposition to hallucinations is suggested. 
COMMENT. The antiepileptic activity of VPA has several proposed mechanisms, including the enhancement of GABA. Increased dopamine release due to decreased GABA activity is suggested as a cause of hallucinations after VPA withdrawal.