One of the problems with describing an illness as psychological is that people think we are dismissing their illness, that we are saying the illness is not real. They think we are either saying that it's all in their heads, or that it's not serious, or that it's just a matter of them needing to "pull their socks up".

I think that might be why people cling to a biological model for mental health problems.

Obviously, we're not saying any of that. I say that there are powerful talking therapies; that these are evidence based and effective for many people; that medication may help although it's probably over-prescribed and it can have unpleasant side-effects; and that some people won't respond to any of that and may need electro-convulsive therapy or other severe interventions.

I agree that people tend to overstate the biological model, and that is a problem. It's a problem because, as you say, we don't know if it's true, and it's a problem because it steers people away from talking therapies.