Patients with a main diagnosis of borderline personality disorder will be recruited and will be randomized for the application of low frequency repeated transcranial magnetic stimulation (rTMS) protol or sham rTMS protocol. A pre-treatment and post-treatment measurement of the severity of BPD symptoms, impulsivity, and aggressive behavior will be carried out in all participants using self-administered questionnaires. All participants will be asked to participate in a passing ball game (Cyberball) with the intention of investigating aspects related to social inclusion / exclusion and measurements will be made regarding planning using the maze test. Participation in the Cyberball and the assessment of the planning will be carried out before and after the application of the treatment protocol.

Inclusion Criteria:

• Outpatient consultant in the Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz.
• Main diagnosis of borderline personality disorder according to DSM-IV-TR.
• In the case of having some type of pharmacological treatment using SSRIs, antipsychotics and / or anticonvulsants, this should be maintained without modifications for at least 2 weeks prior to the start of the study and during the follow-up period.
• Comorbidity with some other personality disorder according to the SCID-II, with the exception of antisocial personality disorder.
• Acceptance of participation in the study by signing the informed consent.

Exclusion Criteria:

• Subjects who did not agree to participate.
• Diagnosis of current antisocial personality disorder, bipolar disorder, psychotic disorders, severe major depressive episode, substance use disorder (except nicotine), and post-traumatic stress disorder.
• Presence of any comorbid neurological disorder.
• Diagnosis of intellectual disability.
• Subjects in whom the use of rTMS is contraindicated: history of seizures, pregnancy, presence of pacemaker, heart disease, and presence of a metallic object.
• Electroencephalographic evidence of some type of abnormality in the excitability of the central nervous system (dysrhythmias, paroxysmal activity, graphical elements suggestive of epileptic activity, etc.).

In case of being requested