The author might be more correct than he imagines. I suffer from bipolar disorder, which was “activated” during a heavy meditation period 5 years ago or so. My therapist now advises me to stay away from it. She says that meditation is a form of “self hypnosis” and that I should stay away from daily practice, which is what I had previously.
Is there any evidence that your bipolar disorder would have activated later or not at all if you hadn't meditated?
What we have is some medications that work with relatively extreme side effects (I am now pre diabetic due to daily Seroquel use) and sort of folk tradition of what to do and not to do - ie bipolar people are advised to stay away from religion for instance.
In my experience both the medication and the folk tradition are mostly right actually, as weird as that might sound. It’s not like psychologists are performing huge studies, but they can see patterns in the individual cases when they are studied in bulk - ie religious individuals might have more psychotic episodes etc.