Peter Brown from Whitby, 46, was last seen at Cross Lane Hospital in Scarborough on the evening of Wednesday May 8.
He had been admitted to the hospital the previous week after suffering with mental health issues and told his wife and hospital staff he was going for a walk with a friend and would be back by 7pm. However, when he failed to return, the alarm was raised as it later transpired he had cancelled the meet with his friend.
Mr Brown, a self-employed painter and decorator, has not been in touch with his heartbroken wife Natalie and their two teenage children since or the hospital since.
There have been several sightings around the nearby area of a man possibly matching Mr Brown's description, prompting the community of Whitby to get behind the search for him.
A facebook group dedicated to the search and updates was established on Tuesday. It already has more than 1,600 members and hundreds have joined the search by scouring woods, the Cleveland Way, back-roads and the former railway line while out walking, cycling, running or as part of organised groups.
Scarborough and Ryedale Mountain Rescue have been giving out search advice and tips, while posters and banners are being distributed to shops, pubs, businesses and even delivery drivers in the area.
The Coastguard, local fishing boats are on the look out, local farms are also being checked and a privately owned helicopter has also been drafted in.
Mr Brown's wife, Natalie, said: "The support from Whitby, I could not be more grateful, it has been over-whelming. It has been difficult too because we are quite private people but I will do anything to get him back. I have opened up our barriers and thought let's do it, people say can I put a banner up or a poster up - let's do it."
The couple have known each other for 30 years and married for 21 and she added that although Peter had had depression in the past his disappearance "is totally out of character".
She said: "Even when he was ill before, he has never done this. He didn't want to be in hospital but he had hot rock bottom and said it was where he needed to be".
However, he had been in hospital in Middlesbrough and Cross Lane for a week before getting an assessment from a doctor, leaving the couple distressed over the length of time taken. Over the last seven months they had also been disappointed with the lack of mental health services in the Whitby area.
Mrs Brown added: "I spent another hour and a half with him and we had been to Dean's Garden Centre for coffee and cake and talking about positive things. We went back to Cross Lane. gave him a hug, told him I loved him and it was a normal goodbye. I think he did not want to be in hospital and needed to get better his own way, I just don't know. I have been ringing and ringing his phone and texting."
She added that his phone was switched off the day after his disappearance but was within a two mile radius and in the Seamer and Weaponess area.
Mr Brown is described as a white, about six feet, one and a half inches tall, and of muscular and athletic build. He is unshaven and his hair is a greying brown colour. When he was last seen he was wearing a blue hoodie underneath a blue waist length jacket, loose grey cotton jogging bottoms, and blue Nike trainers and possibly a blue baseball cap
"I can't bear it, I can't bear the missing. I need to know what's happened, where is he? Every day the missing goes on it is another worse day. It just gets worse and worse and worse. I am heart-wrenched. We are supposed to be together forever and where is he? Everything is going through my head but I just really really want him back."