That’s just wrong. Correlation is a link. The long term high dose use of any CNS depressant correlates with actual depression (the psychological issue [I added the brackets because you seemed to miss when I specified the difference earlier.])
Oh wow, an anecdotal story, well that just proves what you’re saying is 100% correct.
“Pure” psychedelics like LSD and psilocybin rarely cause any sort of abuse, really, but I’ve been on a drug abuse closed ward and the manic people were generally in there because of CNS stimulants of all sorts. Psychedelics are just less likely to yield any long-lasting harmful effects compared to say smoking crack or snorting meth.
So yeah, while a CNS depressant isn’t the a thing that directly causes psychological depression as such, you can probably see how they’re linked from the following analogy; imagine that I tie your legs together. That doesn’t remove your ability to walk, per se, as long as you remove the restraints. But if no-one removes them for 50 years, do you think you’d walk as well as before?
In much the same way, yes, CNS depressants are linked to depression, and alcohol and benzos are the clearest examples.