Consequent upon their emotional vulnerability and early environmental experiences, clients with a BPD diagnosis have skills deficits in a number of areas, including emotion regulation, distress tolerance and interpersonal interactions. The treatment responds to these deficits by providing a modality dedicated to the acquisition of these basic capacities. Most frequently, DBT programmes deliver this function via skills training groups or classes. The timing of these groups may differ according to setting. For example, out-patient settings usually run one group per week of 2V hours duration, whereas in-patient settings tend to provide frequent, shorter groups. All DBT skills classes follow a core curriculum (initially outlined in Linehan [1993b] and more comprehensively extended and described in Linehan [2015a, 2015b]). As this curriculum comprises part of an empirically validated package, most programmes employ it in its entirety. Alternative or modified curricula may be utilized with other client groups (e.g. adolescents or learning disabled populations), provided that the primary function of skills acquisition remains the focus.