Tori Stitt is among the many thousands of veterans from the wars in Iraq and Afghanistan whose post-traumatic stress disorder cases are considered chronic: so severe that treating the disorder into remission through standard practices is expected to take many years.

It is not surprising, then, that many of those veterans are turning to alternative treatments like yoga, acupuncture, herbal remedies and massage therapy. None has proved more popular than service dogs.

Medications and therapy have helped Stitt cope with, though not overcome, the depression, sleeplessness and anxiety caused by post-traumatic stress disorder. But nothing has been more important to her recovery, she says, than Devon, the amiable golden retriever that has become her constant companion.

"It doesn't matter what bad things are going on, I can pet Devon, give him a hug, and they turn around 180 degrees," said Stitt, a former Navy officer who did a tour in Iraq.