Having served on a carrier, I was exposed to a lot of different chemicals and such as well working in the engineering department.
VF-154 sounds like the Black Knights and was originally a Tomcat Squadron, which is now a Hornet Squadron.
I have been exposed to vaccines as well. As far as mental damage, well if he was a screw up his LPO/ALPO would have ripped him a new one every day. Life is not that bad on a carrier, it is a lot of hardwork.
There are sailors that have suicidal tendicies as well. Perhaps the lines for the chow hall, sick call, phones and PX was too much for him to bear?
Max