I mean it is complex. You have genes like ADCYAP1R1 that are part of the turn on stress -> turn off stress loop. Variants in it lead to higher stress, but lower cortisol so so higher neurogenesis. So the group with the variants associated with PTSD (such as https://www.snpedia.com/index.php/Rs2267735 C;C) may be smarter, but have a lower bar for developing PTSD.