Dear Editor The lack of effective oral treatments for severely affected patients with borderline personality disorder (BPD) lead us to frequently use depot antipsychotic medication in our personality disorder unit. BPD is characterized by severe instability of interpersonal relationships, of self-image, and of affects resulting in marked impulsivity. The importance of the disorder is reflected in persistent functional impairment and in elevated suicide rates (Cheng et al. 1997; Paris 2005). There is no current consensus on the best treatment for BPD, and different combinations of oral medications are being prescribed by physicians (Paris 2011; Silk 2011). Furthermore low treatment compliance with oral medication is particularly described in these patients due to their characteristic personal instability which might significantly affect the efficiency of the drugs. For that reason, the possibility that lack of efficacy of oral treatments in refractory BPD patients might reflect the lack of compliance needs to be explored. In that sense, we designed a study to explore the benefits of using a depot IM medication, longacting intramuscular risperidone, in the treatment of BPD patients refractory to previous oral medication trials. A total of 49 BPD patients (30 women and 19 men) were included in the study. Inclusion criteria were the following: (1) 18–45 years of age; (2) diagnosis of borderline personality disorder (BPD) according to DSM IV criteria; (3) score equal or greater than 16 in the Zanarini Rating Scale for BPD; (4) “severely or very severely ill” as defined by a score 5 or greater in the CGI severity scale; and (5) refractory to a combination of oral medications commonly used for BPD treatment. Exclusion criteria were (1) current substance use dependence disorder; (2) life history of schizophrenia, schizophreniform disorder, bipolar disorder, or neurological disorders; (3) unstable medical disease or pregnancy; and (4) demonstrated intolerance to oral risperidone. The sample mean age was 27 years (SD±4.5) and the average duration of the disease was 7 years (SD±3.3). Patients were regularly treated in the day-care hospital due to severe behavioral dyscontrol causing markedly functional impairment. The study was approved by the Institutional Ethical Committee, and all patients signed informed consent. Treatment was started with an initial dose of 37.5 mg IM injection of LA risperidone repeated every 2 weeks, which could be raised to 50 mg as to clinical consideration. Patients were evaluated at months 1, 3, and 6 with clinical scales including the Zanarini Rating Scale for BPD, the Hamilton Anxiety Rating Scale, the Brief Psychiatry Rating Scale (BPRS), the Overt Aggression Scale (OAS), the Clinical Global Impression scale (CGI), and the Global Assessment of Functioning (GAF). Gradual significant improvement of severity ratings was observed from the first month and during the first 3 months of treatment (p<0.001), but no significant changes in the CGI scale were observed between the third and sixth J. L. Carrasco (*) :N. Palomares :M. D. Marsa Institute of Psychiatry and Mental Health, Hospital Clinico San Carlos, C/ Martin Lagos s/n, 28040 Madrid, Spain e-mail: jcarrasco.hcsc@salud.madrid.org