Biochemical abnormalities in basal ganglia and executive dysfunction in acute- and euthymic-episode patients with bipolar disorder: A proton magnetic resonance spectroscopy study.

•We compared the biochemical changes and executive function between acute- and euthymic-episode bipolar disorder (BD) patients.•The lower NAA/Cr ratios in bilateral lenticular nucleus were found in both acute and euthymic BD patients.•Executive cognition dysfunction was also found in both acute- and euthymic-episode BD patients.•Biochemical abnormalities and executive cognition dysfunction are the most likely markers of endophenotypes of BD.