The body of 76-year-old June Wilkinson was discovered in Rushall Canal on October 27, after she went missing from her Park Hall Road home in Walsall.
Black Country Coroner's Court heard evidence from Mrs Wilkinson's husband Colin, who described her as 'a marvellous woman'.
During the hearing it was revealed that the dog walker who later found the body was among those Mr Wilkinson had initially spoken to as he desperately tried to find his wife.
On the day he had been downstairs talking to a friend about fitting a gas fire, and only afterwards realised that a 'click' he had heard must have been his wife leaving the house, the inquest heard.
Giving evidence Mr Wilkinson described some incidents when his wife, a retired book-keeper, had appeared to black out, including at a pensioner's meeting and an 80th birthday party, but no medical reasons for these episodes had ever been identified.
After seeing her GP, Mrs Wilkinson was prescribed some anti-depressants. "The doctor said that she was depressed," he said.
However, the inquest heard that she would often only take half of her medication, or had to be prompted to take it.
On the day of her death, Mr Wilkinson had woken early at around 5am, having not slept well.
"I woke up June at around 6.30am, and she was shaking and sitting on the edge of the bed, holding her head. She said: 'I wish it would go away'."
One of Mrs Wilkinson's sons also told police that she had talked about taking her own life, although she had no history of self-harm.
Describing what happened after he discovered she had left the house, her husband said: "I went around the streets asking if anyone had seen her. I spoke to a dustbin man, a lady with a dog, the postman, everyone. The rest of the family were going around as well."
A statement was then read out from the woman who had been walking her dog alongside the canal, and who made the discovery.
Unsure about what she had seen, she realised when Mr Wilkinson later told her his wife was missing.
She called the police and both they and the fire service attended, locating and recovering the body.
A post mortem concluded that Mrs Wilkinson had died of a cardiac arrest, as a result of drowning, and that this was associated with her depression.
Returning a conclusion of suicide, senior coroner for the Black Country, Mr Zafar Siddique, said: "She was found on the opposite side of the canal, which means she would have had to swim across."