People may actually have mental health issues, but in my opinion the medical industry in the US has a motive to exaggerate them and create medicines. Doctors make most of their money prescribing pills. So there is big incentive to create conditions where there aren't any, get a patient worked up about it and believing it, then sell them some pills.
Ever wonder why doctors try to persuade others to not do their own research about medical conditions? Because it's possible to figure out a solution to a problem without consulting them. This stuff isn't rocket science. One time I discovered the root cause of someone's epilepsy after observing when the seizures occurred. They occurred in the winter during certain months when it's cloudier, darker, and there's less sunshine. Turns out, she had a vitamin D deficiency. Problem solved. Doctors don't want people figuring stuff like that out.