More fundamentally, the fact that all feelings, thoughts and behavior require brain activity to happen does not mean that the only or best way to change — or understand — them is with medicine. We know, for instance, that not all psychiatric disorders can be adequately treated with biological therapy. Personality disorders, like borderline and narcissistic personality disorders, which are common and can cause impairment and suffering comparable to that of severe depression, are generally poorly responsive to psychotropic drugs, but are very treatable with various types of psychotherapy.
There is often no substitute for the self-understanding that comes with therapy. Sure, as a psychiatrist, I can quell a patient’s anxiety, improve mood and clear psychosis with the right medication. But there is no pill — and probably never will be — for any number of painful and disruptive emotional problems we are heir to, like narcissistic rage and paralyzing ambivalence, to name just two.
Anyone who doubts the need for psychotherapy research should consider the case of post-traumatic stress disorder, for which the mainstay of treatment has been exposure therapy.