Mental Health Parity and Identity

One of most celebrated questions in philosophy is the mind/body problem, that is, are the mind and the brain the same thing or different things. If they are different, how, if at all, are they interconnected? Let's take an oblique approach to this in terms of treating mental dysfunction. One often hears arguments for "mental health parity" (as opposed to "mental health parody" which involves humorous sketches including Sigmund Freud) according to which health insurance ought to cover treatment for psychiatric and psychological issues in the same way that it does bodily concerns. The question immediately raised is whether psychological issues are, in fact, simply a subset of physical issues. There is no doubt that mental health overlaps with physical health, that neurotransmitter issues, for example, have behavioral effects, but is mental health completely subsumed under physical health in the same way that, say, cardiology would be or do parts of mental health treatment lay outside of the realm of medical treatment for physical well-being?