[Study of lamotrigine efficacy on behavior disorders affecting patients with severe mental retardation].

Objective: We studied the effect of lamotrigine (LTG) in children/adults with severe mental retardation and behavioral problems.

Methods: We studied 10 cases with the following conditions: (1) severe or profound mental retardation, (2) various behavioral problems and troubles in daily life, (3) insufficient effects or side effects from antipsychotic drugs, (4) ongoing epileptic seizures or EEG indications of epilepsy, (5) no previous LTG administration, (6) the ability to provide informed consent. We began administering small doses and increased to a maximum dose of LTG in 50 mg/day. We determined the improvement of behavioral problems based on family and patient interviews or our medical examinations.

Results: Treatment (still ongoing) has resulted in 7 of the 10 cases showing effects of LTG. Also, 2 of the remaining 3 cases have discontinued medication due to evident changes of mood. Eight cases have showed effects with doses of 10 mg or less per day. We encountered one adult subject who seems to have realized the neuropsychological effect on recognition impairment. We speculated that this patient came to read other people's emotional changes and expected to be either criticized or directed.

Conclusions: Small doses of LTG appear to improve behavioral problems in children/adults with severe mental retardation.