One night in May, Mr X babysat for Dr M and her husband while the couple went to a party.
Mr X stayed the night and when she got home "very drunk and happy" - she had also taken an ecstasy tablet - she sat on his bed and chatted to him before her husband told her to go to sleep.
Accounts of what happened the next day vary. Another doctor from the practice said she had been told the doctor had been found in "a compromising situation" in the bedroom with Mr X.
Dr M had an argument with her husband following this incident, after which the woman arranged care for their children and took a "significant" overdose.
She was admitted to hospital, where she remained for about a month.
Following her discharge from hospital, there were suggestive email exchanges between the two.
"... its driving me crazy that i can't touch you or see you in person ... s*** i never thought i prior to our escapade that i would ever miss you but i do xoxo (sic)," Mr X said in a message.
Dr M replied with "luv u xx".
Mr X's family said Dr M sent roses and champagne on his 21st birthday.
Dr M denied ever having sex with Mr X.
It was further alleged that Dr M encouraged Mr X to mislead investigators about their relationship, but the tribunal found this had not been established.
The tribunal found that, on the balance of probabilities, the two were engaged in a sexual relationship.
"Dr M's known hypomanic state (and the association between hypomania and increased sexual desire) and her contemporaneous marital difficulties, make it more plausible that the clandestine closed personal relationship with Mr X was a sexual relationship," its decision said.
"Her emails/texts illustrate the emotion between them - they are not just friend to much younger friend - they read like lovers."
After the relationship ended, Mr X had multiple suicide attempts and prolonged admissions to hospital and mental health institutions.
"Such an outcome could have been predicted and provides a clear illustration of why relationships between doctors and former patients (in particular, former patients who are known to be vulnerable) are prohibited."
The tribunal sought submissions from the parties on the appropriate penalty for the doctor.