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.

From a mentalizing perspective, in attachment trauma an individual’s experience of adversity is compounded by the sense that they have to be able to bear that experience alone. An overwhelming experience cannot be calibrated and managed within an attachment relationship. Normally another mind provides the social referencing that enables an individual to frame and reframe a frightening and potentially overwhelming experience. In the absence of this, the person cannot process the experience, and further development of mentalizing is disrupted. This chapter describes MBT-Trauma Focused (MBT-TF) work, and it illustrates the three phases of treatment by presenting clinical examples. Intervention focuses on mentalizing, avoidance, mental and behavioral systems, managing anxiety and dissociation, and trauma memory processing. An MBT intervention for complex PTSD that uses psychoeducation, group intervention, exposure, and looking to the future is outlined, and is illustrated with clinical examples.

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.