According to Sapolsky's lecture on depression [1], a stressful childhood experience is 30x more likely to cause depression in individuals with a particular serotonin-related gene variant.

[1] https://www.youtube.com/watch?v=NOAgplgTxfc @ 47:00

No. [1] The context of the whole conversation is traumatic relationships. If anything you are talking about eustress - and traumatic relationships are not beneficial and do not "make you stronger" [2].

[1] https://en.wikipedia.org/wiki/Hormesis

[2] https://en.wikipedia.org/wiki/Eustress#Compared_with_distres...