I'm not sure how much value there is in comparing it with ordinary mortality considering the fairly strict selectivity on handing out TS clearances. You're definitely not going to give one to anyone who looks like an alcoholic or habitual drug user. You'll be less likely to give one out to people who struggle with cravings like heavy smokers or the morbidly obese. Gambling and financial instability are are also exclusionary factors. You would prioritize people who are highly disciplined and exhibit a preference for fitness and a survival mindset in general. So before you get into psychological issues at all, your population will be significantly healthier than the median, less likely to fall victim to homicide, and have fewer life problems than the general population.

A useful comparator is military suicides, which are a growing problem; among enlisted ranks (E1-E4) the rate is about 26/100k. Enlisted personnel tend to be younger, less well educated, have less personal autonomy, and earn less money etc. Among commissioned officers (with command authority) and warrant officers (occupational specialists) the rate falls to ~14/100k, nearly half. Non-combat morbidity exhibits similar disparities. I would guess that the selectivity for TS clearance is more rigorous that the occupational qualification alone.