Psychotherapy as assisted homeostasis: activation of emotional processing mediated by the anterior cingulate cortex.
Although psychotherapy is successful in altering emotional distress, the biological mechanism by which it achieves this has not been the subject of intensive neurobiological investigation. Mindful processing of emotion has been proposed [Mindfulness-Based Cognitive Therapy for Depression, The Guilford Press, New York, 2002] to be a key factor in prevention of relapse in depressive illness and here that hypothesis is developed and extended to include other conditions in which emotion processing may be obstructed or dysregulated. Cognitive therapy, interpersonal psychotherapy, psycho-dynamic psychotherapy and dialectical behaviour therapy, each in a different way and with a distinct emphasis, encourage awareness of emotions and their associated cognitions and biographies, and their varying success may depend on the degree to which they achieve activation of internal healing processes. In eye movement desensitisation and reprocessing (EMDR), the selected target is formatted for endogenous processing which is facilitated and accelerated by eye movements or alternating bilateral auditory or tactile stimulation. The ability to sustain focussed attention on the affect and its visceral, cognitive and biographical components is postulated to activate a homeostatic process of distress resolution, seen most clearly in treatment of post-traumatic stress disorder (PTSD) with EMDR, in which resolution of distress can be intense and rapid while therapist input is non-directive, although supportive, empathic, and non-judgemental. Once the therapist has helped to frame the questions, the patient's brain will find the answers needed for the resolution of the distress and all the components of the traumatic event, whether visceral, cognitive, affective or interpersonal. The anterior cingulate cortex, especially the dorsal and rostral components, is suggested to be the key neurobiological substrate for the efficacious psychotherapeutic relief of distress, and relevant functional neuroimaging studies are summarised. One limitation of some previous imaging studies of emotion is that they have tended to use mild stimuli to discrete emotions. An alternative approach would be to image the brain during reprocessing of an unpleasant event which has profoundly affected the person so that the associated intense emotions could be clearly labelled and correlated with changes in regional brain functioning.