Gabapentin-induced mood changes with hypomanic features in adults

We report two adults who received gabapentin (GBP) and subsequently developed behavioural side effects. Indications for GBP treatment were newly diagnosed epilepsy in one and painful paraesthesiae in the other. Both had no past history of psychiatric or behavioural disorder. Abnormal behaviour consisted of elevated mood, euphoria, and increased energy in both patients, and pressure of speech and decreased need for sleep in one of them. These symptoms were transient and fully reversible. One patient had to discontinue GBP. Behavioural changes were not related to seizure activity. They should be recognized as a possible side effect of GBP treatment in adults.