What kind of therapy is it?

Mentalising is the ability to understand our own minds and the minds of others, and how behaviour relates to mental states. It helps us to establish and maintain positive relationships, and to regulate our emotions. The ability to mentalise arises through relationships with attachment figures in childhood and can, therefore, be compromised if our emotional needs were not always met by caregivers. MBT helps clients learn to mentalise within therapy sessions and then transfer this skill to other relationships.

What problems can it help with?

MBT is effective in the treatment of personality disorders, in particular emotionally unstable (formerly called "borderline) personality disorder, but can be useful for a number of other difficulties, and for anyone who struggles with relationships

What will a typical session be like?

In a typical session, client and therapist will discuss recent occasions on which the client struggled to mentalise in their relationships (including the relationship with the therapist).

What is the evidence?

There is good evidence for the use of MBT with emotionally unstable/borderline personality disorder. There is emerging evidence that is effective in treating other conditions such as antisocial personality disorder, eating disorders, depression, and addictions.

Further reading
Mind
Amazon: Mentalization Based Treatment for Personality Disorders: A Practical Guide Paperback 
Psychiatric Times