At least eight. That’s how many Army veterans Steven Downey knows of who took their own lives.Downey and his friend Drew Oakes, both Army Iraq veterans who graduated together from Stow High School, have climbed out of their own darkness and are now climbing toward Mount Everest.The trek — which began over the weekend after they flew to Katmandu in Nepal — is about bringing attention to post-traumatic stress disorder and veteran suicide.“Twenty-two a day, 8,000 a year,” said Downey, who served as a combat medic in 2006-07 in Iraq, citing the oft-quoted number of veterans who commit suicide.