Christensen surprised the football world last Wednesday by requesting a trade to a Queensland-based club due to personal reasons.
The 23-year-old said he has overcome his private issues and a change of environment would be most beneficial for his future.
"There are a couple of underlying issues, but they're my problem and no one else's," Christensen told media on Tuesday morning.
"I'm on top of everything.
"One of the problems is you've got to admit it.
"I'm not the only one who goes through it. I'll come out in due time and talk about it because I think I can be a really good role model to the community.
"I'll deal with that myself and with the family and friends around me.
"I'm in a happy place and I'll just keep working on being a better person and becoming a good Brisbane Lions player."
Christensen officially became a Lion on Monday after the paperwork was lodged to send the midfielder from Geelong to in exchange for pick No.21.
The Lions received pick No.21 after trading experienced defender Joel Patfull to Greater Western Sydney last Friday.
Christensen said it was a tough decision to leave the Cats and head north.
"At the end of the day, it's my life and I control my own destiny," he said.
"They (Geelong) were completely understanding of where I wanted to head in my life.
"I leave on really good terms with the football club and all the players down there.
"Sometimes you've just got to do what you think is right and what's in your head and what's in your heart."
The 23-year-old midfielder underwent back surgery in February and missed the opening 13 rounds of the season, before returning for eight of the final nine rounds of the home and away season.
Christensen had further back surgery in September and missed Geelong's two finals, but said his recovery is progressing on schedule.
"It's going really well, pretty much pain-free and passed the medical (examination) the other day, so they (the Lions) were happy with it," he said.
"I'm four weeks today and it's about a 12-week recovery, so I'm only a couple of months from joining in training."
After being recruited with pick No.40 in the 2009 NAB AFL Draft, Christensen played 65 games in four seasons, kicked 56 goals and was a member of the Cats' 2011 premiership side.
Christensen, who met with Lions coach Justin Leppitsch last week, said he is eager to start a new chapter in his playing career.
"This change up for me was never about money or anything like that," he said.
"I've copped a bit over the last week, but the people who are giving me stick are the ones who don't care about me.
"I'm more than happy to be up at Brisbane now."
