Martin Ling resigned as Swindon Town manager because of "the stresses of the job", according to chairman Lee Power.
Ling, 49, was in charge of the League One Robins for just 56 days, his first managerial post since leaving Torquay in 2013, having taken three months off because of depression.
"Sometimes in life, things are far more important than football," said Power.
"With his previous health issues, he felt staying was a risk he could not take for the sake of his family."
In a statement on the club website, Power continued: "Martin felt that the stresses of the job were not good for his health going forward.
"He is a football man through and through and is a very honest, hard-working man who loves Swindon Town Football Club.
"Everyone at Swindon Town fully respects his decision and he will always be welcome back at the County Ground."
Ling was in charge of Swindon for nine games, winning five and losing four, and leaves the club 16th in the table.
Following his appointment last month, the former Robins player said his depression had "gone" and that he was "really excited to restart a career that was going very well".
He had been in his previous job at Plainmoor for 18 months before stepping away to recover from a stress-related illness in January 2013 and, although he was expected to return to the role, his contract was terminated three months later.
Ling described the Gulls as "unprofessional" in the wake of his dismissal, and later said "I see depression as a coffee stain I need to get past" and that "it may take a brave person to re-employ me".
Power, who took temporary charge of Swindon's first team after parting company with previous boss Mark Cooper in October, admitted he was "both shocked and extremely saddened" to receive news of Ling's resignation, but that the search for a new manager had "already begun".
He also confirmed that coach Luke Williams would lead the team for Saturday's match against Port Vale.