Bateman 1999.

Study characteristics
Methods	Randomised controlled trial with 2 arms for 18 months Partial hospitalised group receiving mentalisation‐based therapy Standard psychiatric care Duration of trial: up to 18 months Country: UK Setting: partially hospitalised/outpatient
Participants	Method of recruitment: Patients referred Overall sample size: 38 Diagnosis of borderline personality disorder: Diagnostic and Statistical Manual of Mental Disorders, 3rd revision (DSM‐III‐R) Means of assessment: both Structured Clinical Interview for DSM‐IV personality disorders (SCID) and Revised Diagnostic Interview for Borderlines (DIB‐R) Mean age: 31.8 years Sex: 57.9% female Comorbidity: In terms of axis I diagnosis, 70% and 62% had major depression in the intervention and control group, respectively. Inclusion criteria: Patients diagnosed with borderline personality disorder Exclusion criteria Schizophrenia Bipolar disorder Substance misuse Mental impairment Evidence of organic brain disorder
Interventions	Experimental group Treatment name: mentalisation‐based treatment (MBT) Number randomised to group: 19 Duration: up to 18 months Control/comparison group Comparison name: standard treatment in the general psychiatric services Number randomised to group: 19 Duration: up to 18 months Both groups Concomitant psychotherapy: none Concomitant pharmacotherapy: antidepressant and antipsychotic drugs prescribed, as appropriate, polypharmacy was discouraged Proportions of participants taking standing medication during trial observation period: "The initial types and doses of medication were the same for both groups." (Bateman 1999, p. 1565) Exact medication use during treatment unclear: higher medication costs in control group (z‐3.9, P < 0.001) (Bateman 2003, Tab. 1, p. 170) indicates more frequent use of medications in the control group.
Outcomes	Primary Number of patients with self‐harming behaviour in the last 6‐month period Number of patients with suicide attempts in the last 6‐month period Both outcomes assessed with the Suicide and Self‐Harm Inventory, a semi‐structured interview. Secondary Interpersonal problems, assessed with the Inventory of Interpersonal Problems Depression, assessed with the Beck Depression Inventory
Notes	Sample size calculation: not stated Ethics approval: not stated Comments from review authors: Per protocol (22 randomised to each group, only 19 per group analysed since treated per protocol) Information about randomisation and allocation procedure, as well as blinding, was received by email from Dr Bateman.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Comments: Did not use a minimisation method. This method is used to minimise the imbalance between the number of patients in each treatment group. This method maintains a better balance than traditional blocked randomisation, and its advantage increases with the number of stratification factors. It is reported that random assignment was used but it is unclear how the random assignment was performed.
Allocation concealment (selection bias)	Low risk	Comment: Allocation was completed centrally at the university.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Comment: Outcome assessors were blind to intervention group.
Incomplete outcome data (attrition bias) All outcomes	High risk	Comment: Analyses were based on completers only.
Selective reporting (reporting bias)	Unclear risk	Comment: There was no clear indication of selective reporting, but there was insufficient information to permit judgement of 'high' or 'low'.
Other bias	High risk	Attention bias: more attention paid to experimental group participants Allegiance bias: there was no indication given for an allegiance effect. However, as both authors are the founders of MBT, the treatment actually used in the experimental group, an allegiance effect seems not improbable. Adherence bias: "All sessions were audiotaped. Adherence to the treatment manuals was determined by randomly selected audiotapes of individual and group sessions drawn from two distinct 6‐months periods of each case using a modified version of the recommended adherence rating scale." (Bateman 2009, online data supplement, p 1)