Behavior disturbance, phenobarbital, and febrile seizures.

Of 109 children treated daily with phenobarbital following the first fibrile convulsion, 42% developed a behavior disorder, usually hyperactivity. Daily phenobarbital therapy was prematurely discontinued in 54% of the children with behavior abnormality (20% of those treated). The behavior disturbance usually appeared within several months, was no correlated with high blood barbiturate levels, disappeared in 73%, and improved in all children when barbiturate therapy was discontinued. No characteristics of the child, the initial febrile seizure, or recurrence of febrile seizures were significantly correlated with the occurrence of the behavior disorder except for behavioral abnormality preceding the initial febrile convulsion. Eighteen percent of the children who received no phenobarbital developed behavior disorder, most often hyperactivity. The behavior disturbance spontaneously disappeared in 52%. Among these children not given phenobarbital, the group with normal behavior had a greater frequency of family history of seizures, especially febrile convulsions, and a lower frequency of preseizure behavior disturbance; abnormalities of pregnancy, labor, delivery, and neonatal period; delayed milestones; long seizures; abnormal results of neurological examination; abnormal EEG; and recurrent febrile seizures.