Trauma does not cause leaky gut. Leaky gut is from starchy food rotting in the small hair-like appendages in the intestines, eventually causing a hole. This is prevented by eating whole foods with their fiber intact.

Sounds a lot like Lustig's 4 C's: increased dopamine causes less serotonin. Serotonin is made using tryptophan and niacin, which are very hard to get from food unless you eat lot of liver and organ meats. Niacin also acts on the benzodiazepine receptors, making a peaceful and tranquil mood, combines with serotonin increase which creates long term happiness.

Linus Pauling explains: Evolution and Natural Selection
"The process of evolution does not necessarily result in the normal provision of optimum molecular concentrations."
"Of the mammals that have been studied in this respect, the only species that have lost the power to synthesize ascorbic acid and that accordingly require it in the diet are man, other Primates (rhesus monkey, Formosan long-tail monkey, and ring-tail or brown capuchin monkey), the guinea pig, and an Indian fruit-eating bat"
"To synthesize the optimum amount requires about twice as much biological machinery as to synthesize half the optimum amount. As suggested in Fig. 1, the evolutionary disadvantage of synthesizing a less than optimum amount of the vital substance may be small, and may be outweighed by the advantage of requiring a smaller amount of biological machinery."
http://sci-hub.tw/https://science.sciencemag.org/content/160/3825/265/tab-pdf

Some people go through the same traumas, and some turn out better than others. What they eat and how their body absorbs these nutrients plays a big role in this.

This picture is part of Lustig's 4 C's.