Scott McDonald, 40, disappeared from his Divernia Way home on Wednesday last week, and extensive enquiries by top cops have so far failed to return results.
Now investigators are combing through hours of CCTV footage in an attempt to locate Scott, who family members say has been dealing with “personal issues” recently.
The disappearance has been described as out of character for Scott.
A police spokeswoman said: “He is known to go for walks and camping but there is nothing to suggest he has done this on this occasion and his family have grown increasingly concerned.
“Scott has recently been dealing with some personal issues; however, it is out of character for him not to be in touch with his family.”
Sergeant Stuart Gibson, Barrhead Police Office, said: “The photo we have of Scott is from CCTV from a local shop where he was seen five days before he went missing.
“He has suffered a couple of personal setbacks recently and requires daily medication which he has not got with him.
“He keeps himself to himself and rarely socialises but likes to go for long walks and camping – throughout the country – that can sometimes be for days.
“He keeps in touch with his family but has not done so thus far, hence the concern for him.
“So far there have been no confirmed sightings of him and officers are continuing to speak to family and friends for information which could help trace him.
“If anyone has any information or knowledge of Scott’s whereabouts, please contact us as soon as possible.
“His family is very worried and they just want to know he is safe.”
Scott is described as around 5 ft 2 inches in height, with long, brown, straight hair. He also wears glasses. He was last seen wearing blue jeans, dark blue hooded top, dark hat and dark waterproof jacket.
Anyone with information is asked to contact Barrhead Police Office on telephone number 0141 532 6200 or the police non emergency number, 101.