The main objective of the trial is to test whether a single application of botulinum toxin A into the glabellar region will lead to emotional stabilization in borderline personality disorder through paralysis of facial muscles/attenuation of negative emotions.

Afferent feedback from facial muscles is believed to enhance emotional states (facial feedback theory). The facial expression of negative emotions involves facial muscles of the glabellar region. It has been shown that paralysis of facial muscles in the forehead using botulinum toxin A leads to the improvement of depressive symptoms. It is believed that the limited ability to express these emotions alleviates depressive symptoms. As Borderline personality disorder is characterized by negative emotions expressed via facial muscles in the forehead, it is hypothesized that BPD patients could profit from botulinum toxin treatment.

Inclusion Criteria:

1. female
2. 18-40 years
3. diagnosed BPD according to ICD-10 (F60.31) and SKID II
4. stable treatment
5. mastery of the German language
6. effective contraception
7. willingness to and acceptance of treatment with either botulinum toxin A or acupuncture

Exclusion Criteria:

1. Comorbid disorders of all ICD-10 groups o F0,

   • F1 (with exception of F1x.1),
   • F2,
   • F3 (with exception of 32.0 and F33.0),
   • F7 and disorders essentially defining the clinical picture from sections
   • F4,
   • F5,
   • F6.

2. Contraindication for treatment with botulinum toxin A according to the IMP's SmPC (e.g. myasthenia gravis, Lambert Eaton-syndrome or other impairments in neuromuscular function)