As a child I was profoundly depressed. I absorbed everything around me, and the negative stimuli affected me to a far greater degree. I'm not sure if that's innate or if my surroundings were in fact unfortunately negative. It wasn't until the age of 25 (which is itself an interesting age for the prefrontal cortex) that I was better able to control my thinking patterns. I used cognitive behavioural therapy methods in combination with lifestyle improvements (including exercise, sleep, alcohol, drugs, career, friends, money, country, and living arrangements). I figured out how to not hate living. I'm grateful I was stubborn enough to persevere that long. There were dark times.

I had friends who were not bright. They didn't absorb as much as I did. They weren't phased by the negative things around them to the degree I was. I envied them immensely.

It's not just maladaptive thought patterns or beliefs that make it harder to feel happy or function normally. Chronic depression can shape the trajectory of your life in ways that are difficult to undo. So even treatments that increase flexibility(like SSRIs or ketamine) can't necessarily convince you to put on rose-tinted glasses and see the world differently.

In my personal experience, escaping depression also seems to get harder the longer you've had it. It can create catch22 situations and strong path dependencies that severely limit your ability to change the circumstances that are helping keep you depressed in the first place.