If all 'mental illnesses' are caused by chemical imbalances then doesn't that mean that the idea of a 'mental illness' does not exist? If they are caused by chemical imbalances then they are physical in nature and can not be just treated by (psychological) therapy. To me, the idea of psychologists giving suffers from 'mental illness' therapy as treatment is comparable to practitioners of alternative medicine recommending alkaline water as a treatment.

Shouldn't we be focusing on the neuroscience behind these illnesses and the medicinal chemistry [of these illnesses] through research, to reach a proper treatment, in the medical realm.