Botulinum toxin for depression? An idea that’s raising some eyebrows

In our clinical experience, depressed patients who responded to BTA injection report a slow resurfacing of depressive symptoms 4 to 6 months after treatment, at which point they usually return for “mainte­nance treatment” (same dosing, same injec­tion configuration).

Will psychiatrists administer the treatment?
Any physician or physician extender can, when properly trained, inject BTA. The ques­tion is: Do psychiatrists want to? Administrating botulinum toxin requires more labor and preparation than prescrib­ing a drug (Table 2,³¹) and requires placing hands on patients. Depending on the type of psychiatric practice, this may be a “deal-breaker” for some providers, such as those in a psychoanalytic practice who might worry about boundaries.

As a basis for comparison, despite sev­eral indications for BTA for headache and neurologic conditions, few neurologists have added botulinum toxin to their prac­tice. Dermatologists who are comfortable seeing psychiatric patients or family practi­tioners, who are already set up for injection procedures, could become custodians of this intervention.

Which patients are candidates for the treatment?
Patients with anxious or agitated depres­sion might be ideal candidates for BTA injection. A recent study looked at predic­tors of response: Patients with a high agitation score (as measured on item 9 of the HAM-D) were more likely to respond, with a sensitivity of 100%, a specificity of 56%, and an overall precision of 78%.³² So far, no other predictors of response have been clearly identified. Higher baseline wrinkle scores do not predict better response.23 Sex and age do not have any predictive value. The treatment appears to be equally effective in males and females; because only a handful of males have been treated (n = 14), however, these patients need to be studied further.

Is botulinum toxin better as monotherapy or augmentation strategy?
So far, it appears to be equally effective as monotherapy or augmentation strategy,¹⁶ but more studies are needed.

How expensive is it?
Estimates of patient cost include the cost of the product and the professional fee for injection. As a point of reference, for cos­metic purposes, depending on practice loca­tion, dermatologists charge $11 to $20 per unit of BTA. Therefore, 1 treatment of BTA for depression (29 to 40 units) can cost a patient $319 to $800.

When treating a patient with BTA for medical indications, such as tension head­ache, insurance often reimburses the physi­cian for the BTA at cost (paid with a J code: J0585) and pay an injection fee (a procedure code) of $150 to $200. A recent analysis of cost-effectiveness estimated that BTA for depression would cost a patient $1,200 to $1,600 annually.³³ Compared with the price of branded medications (eg, $500 to $2,000 annually)³³ plus weekly psychotherapy (eg, $2,000 to $5,000 annually), BTA may be a cost-effective option for patients who do not respond to conventional treatments. Of course, for patients who tolerate and respond to generic medications or have a therapist who charges on a sliding scale, BTA is not the most cost-effective option.

What about injecting other areas of the face?
We’ve thought about it but haven’t tried it.  There are several muscles around the mouth that allow us to smile and frown. BTA injections in the depressor anguli oris, a muscle around the mouth that is largely responsible for frowning, could treat depres­sion. However, if the mechanism of action is via amygdala desensitization through the trigeminal nerve, treating mouth frown muscles might not work.

Is it safe?
BTA in the glabella has an exceptionally good safety profile.^9,31,34 Adverse reactions, which include eyelid droop, pain, bruising, and redness at the injection site, are minor and temporary.⁹ In addition, BTA has few drug–drug interactions. The biggest com­plaint for most patients is discomfort upon injection, which often is described as feeling like “an ant bite.”

In the pooled analysis of RCTs, apart from local irritation immediately after injection, temporary headache was the only relevant, and possibly treatment-related, adverse event. Headache occurred in 13.6% (n = 8) of the BTA group and 9.3% (n = 7) of the placebo group (P = .44). Compared with antidepressants such as citalopram, where approximately 38.6% of patients report a moderate or severe side-effect burden,²¹ BTA is well tolerated.

Are other studies underway?
Larger studies are being conducted,³⁵ mainly to confirm what pilot studies have shown. It would be interesting to discover other predictors of response and if different dos­ing and injection configurations could strengthen the response rate and extend the duration of effect.

Because of the cosmetic effects of BTA, further studies are needed to address the problem of blinding. In earlier studies, raters were blinded during appointments because patients wore surgical caps that covered their glabellar region.^3,10 Patients did not know their treatment intervention, but 52% to 90% of patients guessed correctly.^3,10,11 Although unblinding is a common problem in “blinded” trials in which some research­ers have reported >75% of participants and raters guessed the intervention correctly,³⁶ it is a particularly sensitive area in studies that involve a change in appearance because it is almost impossible to prevent someone from looking in a mirror.