Depression is an illness, a crippling disease that hurts every aspect of an individual's health whether mentally, emotionally or even physically.
It's the black dog, the voice inside millions of people's heads that continues to influence millions of lives around the world.
It is the reason former South Sydney halfback Joe Williams wants his story told.
You see, Williams has suffered depression for as long as he can remember.
A proud Aboriginal man now residing in Wagga Wagga, Williams recently spoke about his demons in a short documentary titled 'The Enemy Within' detailing how he continues to keep fighting the good fight against the disease that almost ended his life.
Now a professional boxer and dual title holder, Williams doesn't beat around the bush when it comes to his suffering. Still just 31, he says that "without a doubt" the illness cost him his promising NRL career.
"Ask anyone who I played with, against or was coached by and they'll say I didn't live anywhere up to the expectations or potential as a player. Nowhere near it. I was suffering massively from depression and that's why I believe I was so inconsistent," Williams tells NRL.com of his 49-game career with the Rabbitohs, Panthers and Bulldogs.
"When I was playing footy, I can say now that I was an alcoholic and drug addict. Party drugs and prescription drugs were a massive thing for me when I was playing. It took me away from reality.
"I dreaded selection day. I dreaded it every week no matter how good I played the week before. I'd always find something about my game that I might be dropped on. It is no way to live as an NRL player because you're always... worried about the negative stuff."
Clean and sober for now almost nine years now, it was a completely different story not too long ago.
After the breakup of his marriage and another serious relationship soon after, as well as losing his kids and NRL dream, Williams attempted suicide – something he still considers a "scary thought".
It wasn't the separation that led him to the brink though. It was the sense of hopelessness that consumed him afterwards.
"My ego took a massive blow when all this stuff happened," Williams says.
"I felt I couldn't be the father I wanted to be and I knew I could be to my kids.
"People say 'how could you think about suicide when you have beautiful kids?'... but there was also nothing else I could think of, that my kids deserved better and they'll be better off without their dad."
Even to this day, Williams believes he is not in control of his own depression. Rather, he has learnt to manage its effects on him over time.
Now working as an Aboriginal Education Worker at Wagga's Mater Dei Catholic College, Williams credits his fiancé and "saviour" Courtney, who herself battled Leukaemia as a 10-year-old, for keeping him still standing on this earth today.
"I'd be dead and buried long ago if I didn't meet Courtney. She saved my life," Williams says.
"She knows when I'm having a bad day. She knows when I'm having a bad day before I know I'm having a bad day. She's always on top of me that I'm taking my medication and making sure I'm doing the right thing.
"She entered my life for a reason and I can't speak highly enough of her. She's such a gentle soul. She knows all about toughness... and she's here to tell her story and help raise our son. She's a beautiful stepmother to all my other kids too."
For Williams, helping others is how he continues on with his day to day battle. Through boxing and teaching, Williams remains positive.
With the likes of former rugby league stars Nathan Blacklock and Preston Campbell revealing their own fights with mental illness in recent times, Williams believes it's now a matter of sticking together and helping others in the fight against their own troubles.
Ultimately saving lives and raising awareness is the goal for Williams. By revealing his own battle, he hopes to help remove the stigma associated with mental illness.
"The more the NRL gets behind these kind of things, the more we can change kids' lives," Williams says.
"It's not a matter of changing a kid's footy career or helping them earn a bit of money through our beautiful sport of rugby league. It is about saving lives and that's by far bigger than everything a game can do."
"I'm a carer, that's my thing, I like helping people. I like seeing people smile and seeing people achieve their dreams.
"When I'm not busy, I'm sitting down worrying about myself and start listening to the people up inside my head. That's when I start to self destruct. Self-destruction has been a massive thing but me helping others makes me see how fortunate my life is."
His boxing career has played a massive role in helping him continue his own fight within.
As the current WBC Asian Continental and WBF World Junior Welterweight title holder – who had his arm raised over the weekend after defending his Welterweight title and winning the Asian Continental Championship in a unanimous decision – boxing has become an outlet for Williams to learn more about himself every day.
"Every day I go into a boxing gym I learn something, it's not technically but it is something about me," Williams explains.
"Once upon a time I would have to search within myself and all I would have seen is a little boy in there who was scared and who would run away.
"But now when times are tough and I search deep inside myself, I like the man I find."
If you or someone you know needs help, you can call Lifeline on 13 11 14.