A small study made a big name for itself in the media last week when headlines declared that individuals who receive BOTOX injections may also experience weakened emotions.

The full report behind the headlines is available in the June issue of Emotion, a bi-monthly journal affiliated with the American Psychological Association (APA).

Researchers designed this study to investigate a century-old theory called FFH, or facial feedback hypothesis, which theorizes that facial expressions influence emotional experience. In other words, forcing a facial expression will cause an individual to feel the corresponding emotion and vice versa. However, much of the existing evidence to support this hypothesis is based on poorly designed studies.

Since the popular cosmetic injectable BOTOX is a neurotoxin that paralyzes the muscle at the injection site, its administration would inhibit the ability to make certain facial expressions and, theoretically, reduce the associated emotion, which is what researchers hoped to prove.

Sixty-eight women electing to have cosmetic injections - either BOTOX or Restylane – took part in the study. Restylane was utilized as the control in the study, given its similar application style (injection) and non-paralysis effect (cosmetic fillers do not effect muscle movement).

Each participant was shown a set of videos 8 days prior to and 2-3 weeks following their procedure – allowing time for the BOTOX injections to take full effect. The videos, which differed between pre- and post-procedure, were categorized as positive, negative or mildly positive. Each set contained one positive, one negative and two mildly positive videos.

Upon review, the BOTOX group showed no difference in self-reported emotional experience pre- and post-injection when analyzed alone. However, when compared to the Restylane group, researchers noticed a statistically significant difference. Relative to the Restylane group, the BOTOX group showed diminished emotional experience in response to the mildly positive videos but not to the positive or negative video clips.

These findings suggest that facial feedback may play more of a role with regard to mild emotions versus stronger, more intense feelings. The researchers noted that the study results implied “that there are circumstances in which facial feedback contributes to, but is not the sole determiner of, emotional experience”.

The Bottom Line

While this may not raise enough concern to recommend discontinuing the use of BOTOX, the study results certainly yield a few interesting implications.

The unique ability of BOTOX to isolate facial muscle groups will undoubtedly be combined with neuro-imaging technology to lend to future research investigating the facial feedback hypothesis.

Also, this study raises interesting questions regarding the use of BOTOX as a treatment for mood disorders like depression and anxiety.