Lee Bowman's inquest heard it took two months for his body to be found because police assumed he was still alive and "drunk somewhere".
Mr Bowman's family said they told officers repeatedly it was out of character for him not to contact them.
Nottinghamshire Police said "lessons will be learned" from the case.
Mr Bowman's daughter, Corrina Bowman, said not knowing what happened had a significant impact on her mental health.
She tried to kill herself six days after reading anews article in which police falsely saidher father was "alive and well", and was sectioned under the Mental Health Act for her own safety.
Assistant Coroner Abigail Combes said police had been affected by "unconscious bias" due to Mr Bowman's background and assumed he was "missing because he didn't want to be found and was drunk somewhere".
She was so concerned about what happened she intends to issue what is known as aRegulation 28 reportto the College of Policing, to prevent future deaths.
However, the coroner said it was not possible to know whether Mr Bowman's life could have been saved if he had been found earlier.
Miss Bowman hopes what happened to her father will change how police approach other missing persons cases.
"I'm grateful for how the court saw my dad for a human and not his addictions and troubles," she said.
"I'm glad that things are having to change as I don't want my dad to have died for nothing and I'm hoping now that missing people with vulnerabilities such as addiction are handled with the care and respect they deserve."
However, Miss Bowman said she would always have unanswered questions.
"I don't know how to grieve when I don't know how he died," she said.
"The pathologist couldn't guarantee he died that night. What if someone had gone out to look for him? Would he have been alive? Would we have been able to save him?
"I hope it was really sudden. I hope he passed away really quickly and wasn't trapped for days."
Mr Bowman was from Ollerton in Nottinghamshire and was 44 when he died in 2021. He had two daughters, who are now aged 23 and 17.
Corrina, his eldest daughter, said he was "devoted to me and my sister and was extremely protective and family-orientated".
However, she said her father had mental health problems which stemmed from being sexually abused while at a boarding school for children with dyslexia.
His medical records, which were summarised at his inquest, said he was only eight years old at the time of the sexual abuse.
"He was around 16 when his drug use started but he became severely mentally unwell when I was around nine," said Miss Bowman. "That's when his self-harm became quite serious."
Mr Bowman's medical records showed he had a history of anxiety disorder, depressive disorder and substance abuse.
He was an alcoholic at the time of his death and also had liver cirrhosis.
Mr Bowman was last seen by his family on 29 October 2021, shortly before he went to visit his girlfriend, who lived in the village of Thurcroft in South Yorkshire.
His girlfriend told police she last saw him on 31 October, when he had been drinking alcohol.
She said they had a disagreement, her brother hit him in the mouth and she "kicked Lee out of the house".
Families who were trick or treating then saw Mr Bowman in the street and according to their police statements, he looked "disorientated" and was "stumbling about, clearly intoxicated".
One of them posted a photo of him on Facebook, and this showed he had a cut lip.
This was the last time Mr Bowman was seen alive.
His brother, Wayne Bowman, initially reported him missing to Nottinghamshire Police on 2 November, because Mr Bowman normally telephoned his family numerous times a day, but nobody had heard from him.
However, Nottinghamshire Police treated it as a "deliberate absence" rather than a missing person enquiry.
Mr Bowman's father reported him missing again to Nottinghamshire police on 4 November and he was then treated as a missing person.
A media appeal resulted in numerous apparent sightings of Mr Bowman, including by an off-duty police constable.
However, all the sightings were later found to be false.
Assistant Coroner Abigail Combes said: "On the evidence I've heard, these sightings were followed up, although not necessarily thoroughly checked for accuracy.
"These sightings therefore gave false assurances that Lee was alive, and therefore not contacting his family for unknown reasons."
A South Yorkshire PCSO sent an email to Nottinghamshire Police on 24 November which read: "The missing person can be seen in Rotherham Town Centre on a daily basis. He is hanging around with the local drug users and drinkers."
Nottinghamshire Police transferred the investigation to South Yorkshire Police on 28 November and it was closed shortly afterwards.
The case was reopened on 7 December after the family contacted police again to say they had not heard from him.
Detectives were asked to lead the investigation a week later and police eventually found Mr Bowman's body on 3 January 2022, close to where he had visited his girlfriend in Thurcroft.
His body was in a very narrow gap between two fence panels, which were at the end of gardens backing on to each other in Cedric Crescent and Green Arbour Road.
The pathologist who examined his remains could not determine his medical cause of death because of the decomposition.
However, he gave four possible medical explanations:
The pathologist said there was no evidence he died as a result of being assaulted, but this "cannot be reliably ruled out".
"It is possible that evidence of an assault may have been obscured by decomposition and maggot infestation," his report said.
The coroner said on the basis of the pathologist's evidence she could not say whether or not Mr Bowman was already dead on 2 November 2021, which was the day his family reported him missing.
"I cannot say with any degree of certainty when Lee died, and therefore I cannot say whether he could still have been found alive if different decisions had been made," she said.
However, she said she was concerned by "significant evidence of unconscious bias" when it came to how police handled the investigation.
"For example, there were assumptions that Lee led a chaotic lifestyle and was missing because he didn't want to be found and was drunk somewhere," she said.
"I think there's an important issue in Lee's case that his lifestyle has been a factor in the way they have conducted the missing person's enquiry."
She recorded an open conclusion and ended the inquest by thanking Miss Bowman for attending.
"I've been watching how you've been conducting yourself and it is admirable," she said.
"I can't imagine how you must feel about the way you lost your dad and I'm so sorry for you."
Nottinghamshire Police said in a statement: "Our thoughts go out to all of Mr Bowman's family.
"Any lessons that can be learnt from this inquest and for policing as a whole we of course welcome."
South Yorkshire Police said its Professional Standards Department had carried out an internal investigation which had "identified some learning for our organisation around missing people investigations".
Det Supt Eleanor Welsh, force lead for missing people, said: "A report was created and shared across the force, and these learnings are now implemented within teams."
A coroner has said she cannot be sure how a father-of-two died after he fell between two fence panels, because his body was too decomposed.