I tried to follow the DOI link to the underlying article, to see at least its abstract, but that link is dead. I don't see any uptake of this hospital press anywhere outside Science Daily, a press-release recycling service often decried[1] by thoughtful readers here on HN. Another kind reader here found the link to the original paper,

http://www.cmajopen.ca/content/2/2/E69.full

which reports

"Methods We recruited participants from an urban men’s shelter in Toronto, Ontario. Researchers administered the Brain Injury Screening Questionnaire, a semistructured interview screening tool for brain injury. Demographic information and detailed histories of brain injuries were obtained. Participants with positive and negative screening results were compared, and the rates and mechanisms of injury were analyzed by age group.

"Results A total of 111 men (mean age 54.2 ± standard deviation 11.5 yr; range 27–81 yr) participated. Nearly half (50 [45%]) of the respondents had a positive screening result for traumatic brain injury. Of these, 73% (35/48) reported experiencing their first injury before adulthood (< 18 yr), and 87% (40/46) reported a first injury before the onset of homelessness."

In other words, I think this is an interesting idea that deserves further investigation (and, for all I know, despite the statement in the article, has been investigated a lot already), but I have no idea how representative the patients that Dr. Jane Topolovec-Vranic found are of all the homeless people in her country, or what the direction of causation is here (could something that increases risk for homelessness at one and the same time increase risk for traumatic brain injury? very likely yes). Research on how to help people who have suffered brain injuries to recover from those injuries is of course a good idea, as is research on the consequences of those injuries, including social consequences like homelessness. Best of all is to figure out how to reduce risk of suffering such injuries. As the article says, "Additional research is needed to understand the complex interactions among homelessness, traumatic brain injury, mental illness and substance use." I would definitely wonder about the substance use part of that.

[1] Science Daily has been decried so often on Hacker News that I have been collecting those comments for a few years.

http://news.ycombinator.com/item?id=3992206

"Blogspam.

"Original article (to which ScienceDaily has added precisely nothing):

http://www.washington.edu/news/articles/abundance-of-rare-dn...

"Underlying paper in Science (paywalled):

http://www.sciencemag.org/content/early/2012/05/16/science.1...

"Brief writeup from Nature discussing this paper and a couple of others on similar topics:

http://www.nature.com/news/humans-riddled-with-rare-genetic-...

http://news.ycombinator.com/item?id=4108603

"Everything I've ever seen on HN -- I don't know about Reddit -- from ScienceDaily has been a cut-and-paste copy of something else available from nearer the original source. In some cases ScienceDaily's copy is distinctly worse than the original because it lacks relevant links, enlightening pictures, etc.

" . . . . if you find something there and feel like sharing it, it's pretty much always best to take ten seconds to find the original source and submit that instead of ScienceDaily."

Comments about both PhysOrg and ScienceDaily:

http://news.ycombinator.com/item?id=3689185

"Why hasn't sciencedaily.com or physorg been banned from HN yet?"

https://news.ycombinator.com/item?id=3867348

"A useful rule of thumb is that whenever you see anything on sciencedaily.com or physorg.com, unless it's absolute nonsense there's another more direct (and often more informative) source you should link to instead."

http://news.ycombinator.com/item?id=3875529

"Original source:

http://www.nasa.gov/mission_pages/hinode/news/pole-asymmetry...

"What ScienceDaily has added to this: (1) They've removed one of the figures. (2) They've removed links to the Hinode and SOHO websites. (3) They've added lots of largely irrelevant links of their own, all of course to their own site(s).

"Please, everyone: stop linking to ScienceDaily and PhysOrg."

http://news.ycombinator.com/item?id=3867361

"Those sources don't have RSS feeds, and ScienceDaily and PhysOrg have a bad habit of not linking to such things."

http://news.ycombinator.com/item?id=4083766

"Added value in PhysOrg article: zero.

"Please, everyone, stop submitting links from PhysOrg and ScienceDaily. I have never ever ever seen anything on those sites that isn't either (1) bullshit or (2) a recycled press release with zero (or often negative) added value. (Sometimes it's both at once.) It only takes ten seconds' googling to find the original source."