How to learn to make a meaningful study without having an academical background?
Given the comments of yourself and others here, let me make an orthogonal suggestion. Instead of exploring this on your own, you might try to contact someone in either medicine or psychology at a university or research center and speak to them about your ideas. You might provide a useful resource to someone who might be interested in following up your ideas, perhaps by guiding a student already under their guidance. 

But alternatively, your conversation might reveal to you that what you propose has already be well researched. Such a professional contact could, perhaps, point you to the answers you seek. 

This would result in minimal impact on your career, and might provide an interesting research problem to someone. 

Personal contact via an office visit is probably the best and most efficient way to get such a conversation started. An email might be ignored. Your therapist might be able to point you to a researcher.