Positive and Negative Psychotropic Effects of Lamotrigine in Patients with Epilepsy and Mental Retardation

Summary:Purpose: To describe significant positive or negative psychotropic effects of lamotrigine (LTG) observed in epilepsy patients with mental retardation (MR). Methods: Seven mentally retarded epilepsy patients, [5 with Lennox‐Gastaut syndrome (LGS)] who experienced significant behavioral improvements or worsening after addition of LTG to their medication regimen were studied. Results: LTG produced behavioral improvements in 4 patients. Patient 1, a 14‐year‐old girl, had LTG added to valproate (VPA) and thioridazine, resulting in diminished lethargy, less hyperactivity, and more appropriate speech. In a 17‐year‐old boy (patient 2) LTG added to VPA, phenytoin (PHT), and gabapentin (GBP) lessened irritability and hyperactivity. In patient 3, a 41‐year‐old woman, LTG added to PHT, VPA, and carbamazepine (CBZ) diminished lethargy and enhanced her social interactions. In patient 4, a 27‐year‐old man, LTG monotherapy diminished irritability and hyperactivity. Adverse behavioral effects were noted in 3 patients. In patient 5, a 43‐ year‐old man, LTG added to PHT, phenobarbital (PB), lorazepam, sertraline, and thioridazine produced irritability, hyperactivity, and poor cooperation. In patient 6, a 29‐year‐old woman, LTG added to VPA produced frequent screaming, temper tantrums, increased rocking movements, and hyperactivity. In patient 7, a 29‐year‐old man, LTG added to VPA and PHT resulted in severe exacerbation of baseline behaviors, including self‐injurious activity, temper tantrums, and failure to obey simple instructions. Conclusions: In some patients with epilepsy and MR, LTG has significant positive or negative effects on behavior.