Inhibiting the facial expression of negative emotions via botulinum toxin A (BTX)
has been shown to mitigate symptoms of clinical depression in randomized controlled
trials. This retrospective case study sought to reproduce the beneficial effects of
BTX in a naturalistic setting for major depressive disorder and collect casuistic
data on its effect on other mental disorders. Moreover, we describe symptom development
across multiple treatment cycles with BTX, and assess the implementation of additional
injection targets in the lower face region. Participants were N = 51 adult psychiatric
outpatients mainly seeking treatment for depression. Over 50% suffered from comorbid
psychiatric conditions, predominantly generalized anxiety disorder (GAD) or borderline
personality disorder (BPD). A pre-post case series design was adapted. All participants
received BTX-injections in the glabellar region on at least one occasion. Some received
additional injections in the mouth region and over multiple treatment cycles. Treatment
response was followed up by self-rated scales at varying time intervals post treatment.
The results showed that BTX may yield favorable outcomes across multiple and comorbid
mental disorders, especially, however, for patients suffering from depression. It
potentially prevents the recurrence of clinical symptoms if applied regularly. Adding
additional regions of the face does not seem to be superior over applying it to the
glabellar region alone. The results add to the growing evidence that BTX therapy is
effective in alleviating symptoms of depression. Positive effects can be sustained
and reinstated, when applied over multiple treatment cycles. Observed symptom reduction
in other psychiatric disorders was less pronounced. Further research is needed to
understand the mechanisms by which BTX therapy reduces psychiatric symptoms.
