Scientifically speaking, why is reddit a bastion for autism whereas 4channel is just a mellow hangout of shitposts and spam?

For example, I'm on r/biochemistry and there is one poor simp who is planning on becoming an hero because he can't get a job with his biochemistry degree.

There is another moron who dropped out of school 2 times over the past 10 years and is asking whether he has a shot at getting accepted to grad school with no research experience.

Why does reddit attract the mentally unstable? Is it because they enjoy getting their cheeks busted?