The anterior cingulate cortex (ACC) is important for emotional and cognitive processing. However, the mechanisms that underlyingie the its involvement of the ACC in the control of behavioral responses are largely unknown. Here, we show that fatty acid-binding protein 3 (FABP3), a polyunsaturated fatty acid chaperone, regulates GABA synthesis through transcriptional regulation of Gad67 in the ACC and that methionine restores normal Gad67 expression and behaviors in Fabp3 knockout mice. Future investigation into the cellular and molecular mechanisms that underlie how methionine treatment restores the phenotypes caused by FABP3 deficiency may shed light on the pathomechanism of various psychiatric diseases with abnormal behaviors. Fabp3 knockout mice are a useful animal model for exploring the involvement of epigenetics in these mechanisms.