He was emotionally unstable.

他情绪多变。

《柯林斯英汉双解大词典》

The rest were impulsive and emotionally unstable.

而其余的人则易冲动，情绪不稳定。

youdao

Psychological slope not only people emotionally unstable, and will indirectly and directly affect health.

心理斜坡不但使人情绪不稳、且会间接、直接地影响健康。

youdao

After she killed her mother, she was diagnosed with schizophrenia with emotionally unstable personality traits.

BBC: Nicola Edgington

The court heard Mansell had a condition described as an emotionally unstable personality disorder.

BBC: Angelo Rodrigues stabbing: Neighbours jailed for murder

When arrested Rahman denied causing the fatal injuries claiming his wife was emotionally unstable and would self-harm.

BBC: Solicitor Mohammed Rahman guilty of beating wife to death