Easy!

Just don't do anything, ever.

Wait, that can't be right...

Hey, guys Tara here for DNews, and if you've ever visited any major city in America, then you'd know that homelessness is a growing problem here.

The city of San Francisco spends $200 million every single year trying to get homeless people off the streets.

And while many attribute their lifestyle to laziness, or drug addiction, or a dwindling economy, a new study says that traumatic brain injuries could be an underlying cause.

A team of researchers at St. Michael's Hospital in Toronto looked at data from 111 homeless men ages 27-81,

and found that almost half of them had experienced a traumatic brain injury at some point during their lives.

And 87% of them occurred before the men lost their homes.

Some had sustained multiple brain injuries with assault being, overwhelmingly, the most common cause.

Sports-related injuries and motor vehicle collisions were also huge contributors.

But for men under age 40, the number one most common cause of brain injury was a fall resulting from drug or alcohol-related blackouts.

Now this brings up an interesting dilemma.

Because it's already been shown that traumatic brain injury leads to aggressive behavior, violence, and impulsivity.

But, by the same token, aggression and impulse control disorders increase the likelihood of traumatic brain injury.

So it's kind of a chicken-and-egg situation, where both problems exist and they just potentiate one another.

Of course there's no arguing that these kinds of injuries worsen pre-existing conditions.

A 2008 study from a different group, showed that traumatic brain injuries increase the likelihood of seizures, mental health problems, drug problems, and overall poorer physical health.

This challenges the notion that being homeless is a conscious decision, but it should also serve as a warning sign to parents whose children have sustained traumatic head injuries.

Just because someone looks ok on the outside, doesn't mean they are on the inside, and that's good advice for all of us.

As always, if you have questions or comments about this episode, feel free to leave them down below, and for more episodes of DNews - subscribe here.