Bianchini 2019.

Study characteristics
Methods	12‐month trial with 2 arms: Standard dialectical behavior therapy (DBT) + treatment‐as‐usual (TAU) within the forensic hospital Duration of trial: 12 months Country: Italy Setting: hospital (forensic)
Participants	Method of recruitment of participants: participants recruited from men consecutively detained as patients in three high intensity therapeutic facilities Sample size: 21 Diagnosis of borderline personality disorder: measured by the Personality Assessment Inventory (Morey 2007) Means of assessment: diagnosis confirmed in a clinical interview by a psychiatrist Mean age: 41.79 years (standard deviation = 8.14) Sex: 100% males Comorbidity: not stated Inclusion criteria Criteria for borderline personality disorder History of violence Exclusion criteria Cognitive deficit (intelligence quotient (IQ) < 70) Comorbid neurological diseases
Interventions	Experimental group Treatment name: DBT + treatment‐as‐usual Number randomised to group: 10 Duration: 12 months (once‐weekly individual therapy (60 minutes), once‐weekly group sessions (120 minutes)) Concomitant psychotherapy: treatment‐as‐usual included social skills, and cognitive remediation Concomitant pharmacotherapy: treatment‐as‐usual included pharmacotherapy Control/comparison group Comparison name: treatment‐as‐usual (pharmacotherapy, social skills, cognitive remediation) Number randomised to group: 11 Duration: 12 months Concomitant psychotherapy: not stated Concomitant pharmacotherapy: not stated
Outcomes	Secondary Affective instability, assessed by the Difficulties in Emotion Regulation Scale, total score Impulsivity, assessed by the Barrett Impulsiveness Scale, total score
Notes	Sample size calculation: no Ethics approval: The study was approved by the Local Ethic Committee. Comments from review authors: none
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: “Each pair was randomised into either a group receiving 12 months of DBT along with other therapies available in the high security hospital (pharmacotherapy, social skills, and cognitive remediation) or a group receiving the other usual therapies alone” (pg. 124). No further details provided
Allocation concealment (selection bias)	Unclear risk	Comment: the authors did not specify the process of allocation.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Comment: outcomes were self‐reported.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Comment: Dropouts were not explicitly specified. However, the authors stated that “All participants completed at least 90% of the DBT sessions offered.” (p.127) Also “Once patients have been admitted […], they are required to complete any treatment programme offered; if a person does not, s/he may be referred back to the magistrate, who must consider if the individual is in breach of his/her order.” (p. 123) No details about the proportion of TAU completers, but, since all participants were convicted inpatients of a secure hospital, “completion” of TAU treatment was very likely. “All participants were reassessed after completion of the DBT programme or, for the control group, after the same time had elapsed”. (p.125)
Selective reporting (reporting bias)	Unclear risk	Comment: no protocol was available.
Other bias	High risk	Adherence bias: therapeutic adherence not assessed Attention bias: DBT (once weekly individual plus group therapy) offered additionally to TAU, hence more attention spent to DBT group Allegiance bias: there was no indication of allegiance bias.