By Martin HickmanA phone-hacking journalist told the Old Bailey today that he became so depressed at the News of the World that he "self-medicated" with cocaine.Giving evidence at the phone hacking trial, Dan Evans estimated that while at the NoTW he used cocaine "every couple of weeks.""It was something that's been in and out of my life over the years," he said. "I was self-medicating."Asked by Andy Coulson's counsel, Timothy Langdale QC, what he meant by self-medicating, Evans said: "When people are depressed and unhappy and not coping... it's not uncommon for them to find ways of dealing with their stress in different ways."The lawyer asked: "Was all this unhappiness because of all the hacking you had to do?"Evans - who has pleaded guilty to hacking phones at the NoTW between 2005 and 2010 - told the jury: "Carrying an enormous secret and delving illegally into the lives of people who didn't deserve it, made me unhappy."He said that he had also been depressed at the Sunday Mirror - where he hacked phones between 2003 and 2004.Referring to his career there, Evans, who told the jury yesterday he is now clean of drugs, said: "I was drinking too much. I was using drugs. I was depressed and anxious…and unhappy in general. I was feeling increasingly compromised professionally and personally."He told Mr Langdale he had continued using drugs at the News of the World.Why, then, had he moved to the paper?, Mr Coulson's lawyer asked.Evans said he had been promised a more investigative role at the four million-selling redtop, adding that he also wanted to work for the "market leader.""I wanted to progress my career. I was ambitious," Evans recalled."I wanted to try and start afresh and do things on my own terms. I was a pretty young guy and made mistakes."He told the court: "I've been in therapy for the last year and a half. It hasn't been a very easy decade in my life."He insisted hacking had been an "open secret" at the NoTW.Referring to his job interview with Mr Coulson, then NoTW editor, at a hotel in Aldwych, London, in 2004, Evans said: "Hacking was the hook. That was clearly what Andy was interested in."Mr Langdale asked: "That was what Mr Coulson wanted - is that what you're telling me?" Evans replied: "Absolutely."The reporter said that it was "widely known" among NoTW journalists that hacking was going on. He told the court: "The office cat knew."Later, he said: "The truth is that Andy Coulson knows exactly what went on on his watch."Mr Langdale responded: "Is there anything else you would like to throw in about Andy Coulson?" "Not at this time," Evans replied.Mr Langdale will continue his cross-examination tomorrow morning. Mr Coulson denies conspiring to hack phones.