According to the news agency, the depression was triggered by the fact that O'Sullivan — a non-Japanese citizen — was forced to give reports in the Asian language, though he had previously informed the organization that his language skills were rather controversial.
The former head also filed for damages against the Tokyo-based organization in a bid to overturn his dismissal, the news agency added.
O'Sullivan headed a major North American labor federation in Los Angeles before taking office before joining Amnesty International Japan in March 2017. During six-month probation, the employer added a new requirement for the Japanese branch's head — reports and presentations were to be given in Japanese. As a result, he was forced to communicate with the board of directors in Japanese.
In September 2017, O'Sullivan was diagnosed with depression and became unable to work due to ill health. Later that month, Amnesty International Japan dismissed him, citing his working attitude among the reasons.