The development of mentalizing and non-mentalizing is discussed along with the importance of mentalizing as a psychotherapy process in the treatment of mental health problems. A defining feature of mental disorder is the experience of “wild imagination,” and we consider that mentalizing difficulties—that is, the tendency to get caught up in unhelpful ways of imagining what is going on both for ourselves and for other people—are the price we as a species pay for the immense benefits of the human imagination. Mental health problems arise when mentalizing is lost and we use mentalizing processes that are from earlier stages of development. The relationships between mentalizing, use of low mentalizing modes, epistemic trust and distrust, and social processes are summarized.

There is considerable evidence of mentalizing problems in patients with eating disorders, with non-mentalizing modes, especially in relation to body weight and shape, being dominant. The mentalizing model assumes the existence of developmental vulnerabilities, especially during adolescence, and that the range of different symptoms associated with eating disorders may have the common function of being attempts at social self-regulation. Controlling eating is a way of managing social and emotional developmental milestones that the person perceives as insuperable. Patients with eating disorders become stuck in a low mentalizing experience of themselves and their bodies. Clinical treatment based on this formulation is discussed as it is applied in a combined program of individual and group psychotherapy, together with psychoeducation.

A mentalizing framework for understanding narcissism is outlined, and the resulting modifications of basic mentalization-based treatment (MBT) for narcissistic personality disorder are discussed. Treatment of patients with pathological narcissism requires an emphasis on empathic validation and support of the vulnerable “I-mode.” The dangers of not recognizing low mentalizing in narcissistic functioning are also discussed, as both patient and clinician can fail to recognize pretend mode, which may masquerade as “we-mode.” Together the patient and the therapist may then set up a pretend therapy that can be interminable and that functions only to fuel the mental narcissistic structure. A clinical example of a patient in treatment is used to illustrate the process of treatment.