The little I know: I would agree with what you’re saying only with regards to illnesses like psychosis and schizophrenia.
When it comes to things like lack of concentration (ADD), depression and anxiety, there are many observers who reasonably believe, on scientific grounds alone, that medications are over-prescribed for these conditions.
The idea that anyone experiencing depression should be on medications, and that this is the only way to relieve the depression, is not accurate. Changing one’s thinking patterns (whether through secular therapy, religious counseling or other means), diet, lifestyle, exercise, social interactions, volunteering, writing in a journal, etc. also have profound effects on mood, and in many studies the magnitude of the effect is similar to or greater than that of medications.
Recent meta-analyses of articles measuring the effects of psychiatric medications for depression concluded that most of them have virtually no effect. There is documented corruption within drug companies, throwing away studies that show their drugs have bad side effects or have no effect. Some medications actually increase the risk of suicide (and even have that printed on the package under federal law).
Medications may be called for in many circumstances, but there are certainly grounds for skepticism, for believing that they are over-prescribed, and for considering them a last resort rather than the first line of defense for mood or concentration problems.