01 · Origins
A developmental account of the mind
Mentalization-Based Therapy (MBT) was developed in the 1990s by Peter Fonagy, Mary Target (today Hepworth) and Anthony Bateman at the Anna Freud Centre and University College London. It draws together attachment theory, psychoanalysis and developmental neuroscience into a unified account of how human beings come to understand themselves and one another.
02 · Definition
Mentalizing, defined
Mentalizing is about remembering that we humans are mental beings.
We all have minds. We think, feel, intend, react, want, wish, dream, lie, pretend, tell the truth, mistrust, panic, become paranoid. Well, you name it.
And we affect each other mentally. We feel something when someone we care about is disappointed in us. It hurts when we feel misunderstood. And we often feel safer with someone who seems to truly get us.
But none of us, as far as we know, has X-ray vision.
So basically, we cannot know exactly what another person feels, thinks, wants, or means in a given moment. And sometimes we do not fully know what is going on inside ourselves either. Inner life can be messy.
So we are left to guess.
That guessing is mentalizing.
More formally, mentalizing means trying to understand human behaviour as connected to inner mental states, such as needs, desires, feelings, beliefs, goals, intentions, and reasons.
Sometimes mentalizing just flows. You are having a good day. You feel connected. Other people make sense. You make sense to yourself.
At other times, people become impossible to read. We misunderstand, overinterpret, shut down, or feel threatened. The same can happen in relation to ourselves: we no longer understand why we react the way we do.
Mentalizing is easily lost under stress.
And when that happens, the social world can quickly start to feel confusing, lonely, or dangerous.
"Holding mind in mind." (Peter Fonagy's famous phrase).
03 · The clinical model
Primarily a stance, and somewhat a technique
In MBT treatments, the therapist adopts a position of authentic not-knowing and wanting-to-know-more, curious about the patient's mind and modelling the very capacities the patient is working to recover. Sessions are structured but conversational; interpretations are tentative; the therapist's own mind is part of the work.
- ·Curiosity and not-knowing/wanting-to-know-more
- ·Affect-focused attention
- ·Working in the here-and-now
- ·Repair after rupture
- ·Collaborative formulation
- ·Modelling the mentalizing process
04 · Evidence
Three decades of research
Primarily, MBT has an evidence base regarding psychotherapy for borderline personality disorder, with sustained gains shown at eight-year follow-up (Bateman & Fonagy, 2008), and for antisocial personality disorder (Fonagy et al., 2025). Adapted protocols and ongoing research exist for several other contexts, such as for example adolescents (MBT-A), children (MBT-C), families (MBT-F), eating disorders, and trauma.