Andrew Quigley was reported missing two weeks ago when he failed to return home from a night out.The 20-year-old was last seen in the Galliagh/Shantallow areas of the city at around 2am on Saturday 18 January.Items belonging to him, including a mobile phone, were found on the Foyle Bridge.Hundreds of volunteers have entered a third week of searches but his family fears he may have drowned.Andrew became reliant upon drugs after a number of personal difficulties, including the death of his father.His mother Colette has told UTV she believes Andrew would still be here if addiction services in the North West were better."Andrew has tried to take his own life a few times before this but I just thought it was a phase that he would get past, that we could eventually turn that corner and he would grow up and unfortunately not," she said.As Andrew was gripped by the drug methadone, his family tried to get him help but found it difficult."He was just a totally different young fella. He was angry, he was frustrated, sometimes violent," Colette explained.Colette said Andrew had even tried to get himself jailed to help bring his situation under control.She said the experience has been "torture" for her.Andrew had a brilliant life and a brilliant life ahead but it is just heartbreaking. Everyone misses him so much.Colette Quigley"He was so much loved and he would say to me 'I know you love me. I know everybody loves me'," she said."But he was just so unhappy and I would ask him why he was taking this stuff because 'you're not happy'. 'I wouldn't take something that was making me unhappy.'"But I don't know. You bring them up. You teach them to walk and you send them out in to the big bad world and that is what happens."She added: "People need help, it is as simple as that."I am standing at that river and I am saying to all of his friends please, please just stop taking it, stop taking it, it is really ruining your life and you have a life."Andrew's story has strengthened a campaign for a specialist detoxification clinic in Derry.Currently the nearest facility is in Omagh and it could be closed under proposals to centralise services.A large crowd attended a rally in the city at the weekend to support the demand.Dermot Quigley, Andrew's uncle said local people would not be satisfied until a centre is established in the local area."The issue of drugs in Derry at the minute is at crisis point," he told UTV."I have been contacted by parents and families throughout the town who are suffering the exact same story so we are going to have to do something about this."