Back up Hoss...
I do not see how you can conclude that the environment is MORE important. You need to qualify the conditions under which you making these conclusions, and do not believe you are.
UNDER the conditions of torture, the fact that some develop mental disease and some don't is due to genes.
UNDER the conditions that no torture exists, the fact that no one develops mental disease is due to environment.
HA!
Plus, if you think about it on a timeline...
First, torture can be seen as a form of environmental pressure.
Second, if there was not torture in the past, then of course there would not be "torture" adaptations.
Third, by the very fact that your applying pressure, your selecting for individuals who may have genes that increase their chances of survival under said conditions. (i.e. the folks with mental disease aren't looking to good in the reproduction arena)
Therefore, under natural selection, some sort of torture adaptation should emerge as dominant... (Cut me some slack on the timeline issues, and the extent to which this torture is applied...of course if its too severe, no one reproduces)
So yes, you are not going to see a "torture" gene, but over time you might.