The American military made efforts to recruit people who would be less likely to drop out from combat stress. There's probably an equivalent there: combat stress, then stress reaction, and later, PTSD. Toward the end of the war, they were screening out up to 70% of their recruits, saying, no, you're too high a risk. Yet this had no significant impact on the numbers of soldiers with CSR.
Other than a few people, those actively distressed and suffering from symptoms of a mental disorder at the time, or who are perhaps mentally retarded and untrainable, there aren't many others you can screen out. If your expectation is that we're maybe going to be able to find a configuration of factors that would say no, that person can't be recruited because their risk is too high, I don't think we're there yet, or able to identify that.