Charity volunteer Timothy McComb, 38, was found hanged in his flat at Cottingley Court in south Leeds on August 26, 2016, the jury inquest at Wakefield heard.
The jury concluded that Mr McComb died by suicide, Wakefield Coroner's Court was told.
After the verdict, Mr McComb's sister Kate Siobhan, said: “We are hugely disappointed by this conclusion.
"Timothy was a loving son and brother who was desperately trying to find support for his complex issues."
She added: "The whole process has been frustrating and traumatic. We do not feel our concerns have been addressed."
Cathy Woffendin, director of nursing, professions and quality at Leeds and York Partnership NHS, Foundation Trust, said after the inquest: “On behalf of the trust, I’d like to offer our sincere condolences to Timothy’s family.
"We welcomed the opportunity to work with Timothy’s family to develop an action plan, which has been implemented to ensure the care we provide is safe, effective and joined up with our partners. We thank them for their commitment to improving the care of patients in the future.”
Mr McComb, who had been a volunteer at Leeds homeless charity St George's Crypt, was found dead four days after being taken to St James’s Hospital after claiming he had overdosed on his prescribed medication.
He was seen by an A&E liaison nurse, who told the inquest he did not believe Mr McComb was at a high risk of harming himself.
Mr McComb returned to Cottingley Court , where he took his own life.
The inquest jury heard Mr McComb had been helped by support worker Gary Wright for just over a year.
Mr Wright worked at the time for West Yorkshire Finding Independence, a National Lottery-funded project to support people with multiple complex needs.
He told the inquest that Mr McComb was continually worried while he was at Cottingley Court that he would become homeless.
But Mr Wright said at no stage did he have any concerns Mr McComb would take his own life.
When asked what his reaction was when he was told of Mr McComb‘s death, Mr Wright said: “I was completely shocked. I didn’t think that he would go to that extreme measure.”
Cottingley Court manager Robert Gillum said six-month tenancies were offered by a private company and that his staff were there to help residents transition into independent living.
Area Coroner Jonathan Leach asked him: “If I said Timothy’s concern was irrational and with no foundation, would that be fair?”
Mr Gillum replied: “Yes.” He added: “No one has ever been made homeless from Cottingley Court.”
The inquest heard that Mr McComb had a history of contact with mental health services, including in 2014, when he was admitted to a psychiatric hospital in a drug-induced psychosis.
The inquest heard both Mr McComb's designated community mental health worker and Gary Wright were on annual leave at the time of his overdose and death.
But information about his hospital admission had been passed on to a duty community mental health worker.
The inquest heard that doctor Hari U Pai, who saw Mr McComb in the days before his death, was shocked by what happened and ceased working as a GP. He said: “It’s really affected me.”
When asked if he had concerns about Cottingley Court, Dr U Pai said he did.
He told the hearing: “Yes. Because they were doing repeated self-harming.”
Mr McComb’s sister, Katie Siobhan told the inquest that in the months before his death, there had been a “marked improvement” in Mr McComb’s mental health and he had been volunteering at St George’s Crypt in Leeds.