Olanzapine-induced electroencephalographic changes reversed by lamotrigine
A 13-year-old right-handed Caucasian boy underwent inpatient video-EEG telemetry for investigation of paroxysmal spells of inattention. Spells were of recent onset, and had only been observed at school. His mother related a tendency for him to become engrossed in reading, such that he would not respond to his name being called. She suspected that the spells observed at school were of a similarly benign nature. Nevertheless, due to a concern for nonconvulsive seizures, he was admitted for monitoring. Other medical history included bipolar disorder diagnosed at age 5 years, for which he received OLZ 15 mg/ day and LMG 200 mg/day. Physical examination revealed a well- looking, although reticent, child with no neurological findings. Brain magnetic resonance imaging at 3T was normal.\nBaseline awake and asleep EEG recording on Day 1 of hospitalization, while on his home medications, was normal. LMG was thereafter abruptly tapered to zero with the intent of inducing electrical epileptiform activity and/or paroxysmal clinical events. EEG in wakefulness from Day 2 onwards showed intermittent bursts of generalized slowing with frontal maximum that increased dramatically with hyperventilation []. Repeated bedside testing for attention, language, memory and motor function during hyperventilation-induced EEG changes was normal. No spontaneous pushbutton events were recorded. Photic stimulation produced a driving response only. The interictal sleep EEG was normal in all sleep stages. His mother reported some lability of mood during this time of LMG withdrawal. The drug was reinstituted on Day 5 at the original dose, resulting in a marked improvement in the EEG abnormalities [] within 24 h, accompanying an immediate improvement in mood. He was discharged to outpatient psychiatric follow-up on Day 6, with a diagnosis of nonepileptic inattention and without medication changes being made.