system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why is it that a lot of homeless people in the US are veterans? 

A lot of times when I see homeless people in real life or on TV, they are veterans. Usually older men, but sometimes younger. Why is this? I'm sure PTSD plays a factor, but aside from that, what is it that makes it difficult for veterans to return home and work/be able to afford to live?
gpt
Veterans represent 11% of the adult population, but 26% of the homeless population.

Causes:

* Lack of income due to limited education and lack of transferable skills.  Not everyone services weapons systems for F-16's, a lot of the military does mainly unskilled physical labor.

* Combat-related physical and mental illness.

* Substance abuse problems, often secondary to combat trauma or the stresses of military lifestyle.

* Weak social networks due to problems adjusting to civilian life.