The Psychiatric Experts

These professionals work according to the Diagnostic and Statistical Manual of Mental Disorders in the US (DSM-5) and the WHO's International Classification of Diseases in the rest of the world. These documents assume as given a chemically determined model of what a human is. If I, with no specialised training in the arcana of Psychiatry, come along and point out that if this model is inappropriate to describe what a human is, as it leaves out moral agency and responsibility for example, and that these omissions constitute a catastrophic error, where does this leave the status of such 'expertise' and of the man in the street like me?