The expressions we make on our face affect the emotions we feel.

Botox, short for botulinum toxin, is just one of several brands that are available to those who wish to be injected every three to six months to reduce the appearance of wrinkles.

These injections smoothen wrinkles by paralysing the underlying muscles that cause them. In a new study, participants who received these injections reported less emotional response to video clips than their counterparts who received a different treatment that does not paralyse muscles but adds volume to facial folds and wrinkles.

An assistant professor in the department of psychology at Barnard College in New York City said that “for at least some emotions, if you take away some part of the facial expressions, you take away some of the emotional experience”. Joshua Ian Davis, a study researcher, added that “whether this is a benefit or a detriment depends on your goals”.

At a conference last year, psychologist Michael Lewis of Cardiff University presented research that showed many women who have had Botox to get rid of laughter lines can feel depressed because they are no longer able to smile properly.

Generally, we assume that our facial expressions reflect, rather than direct, our emotions. However, it is more complicated than that. “The expressions we make on our face affect the emotions we feel. We smile because we are happy, but the act of smiling itself also makes us happy,” explains Dr Lewis.

Dr Lewis’s findings are the latest to suggest that the world’s favourite anti-ageing drug could be doing more than simply freezing our facial muscles – it could be changing the way we think and feel.

It may seem unlikely that paralysing the muscles in our face could affect our brain; however, the idea that facial expressions can influence emotions is a recognised psychological phenomenon.

The facial feedback mechanism goes back as far as Charles Darwin, who had stated that: “The free expression by outward signs of an emotion intensifies it. On the other hand, the repression, as far as this is possible, of all outward signs softens our emotions... Even the simulation of an emotion tends to arouse it in our minds.” Darwin was among the first to suggest that physiological changes caused by an emotion had a direct impact on, rather than being just the consequence of, that emotion.

The injections smoothen wrinkles by paralysing the underlying muscles that cause them

This theory has had many developments and is an interesting piece of research in itself for those who are interested. However, in 1988, in an attempt to provide a clear assessment of the theory that a purely physical facial change, involving only certain facial muscles, can result in an emotion, Strack, Martin & Stepper devised a cover story that would ensure that participants adopt the desired facial posing without being able to perceive either the corresponding emotion or the researchers’ real motive.

Told they were taking part in a study to determine the difficulty for people without the use of their hands or arms to accomplish certain tasks, participants held a pen in their mouth in one of three ways. The lip position would contract the orbicularis oris muscle, resulting in a frown. The teeth position would cause the zygomaticus major or the risorius muscle, resulting in a smile. The control group would hold the pen in their non-dominant hand.

To summarise this research study, the psychologists showed that the participants who held a pen in their teeth in a position that used the same muscles as a smile found a cartoon more amusing than those who held a pen in their lips in a way that stopped them from smiling.

The resulting theory is that drugs which prevent us from being able to make a particular facial expression interfere with the messages that go back and forth between the face and the brain, resulting in a struggle to feel the things we would normally feel when making that facial expression.

Dr Lewis is not the first to suggest that Botox could have a role to play in mental health. Over the past few years, a growing number of doctors have suggested that Botox could be used as an anti-depressant.

The theory is based on the same facial feedback mechanism, but proponents argue that if you paralyse only the muscles involved in frowning and not those involved in laughing or smiling, you can prevent people from feeling sad.

In a book called The Face of Emotion – How Botox affects our Moods and Relationships, a US dermatologist, Eric Finzi, explores this idea. He says: “My theory is that by preventing the physical action of frowning, we interrupt this feedback loop and reduce the number of negative messages the brain is receiving, creating a more positive outlook.”

Many women have reported how their emotions have changed after treatment, and also other people’s reactions to what appears to them to be an emotionless face, resulting in misunderstandings at sensitive times.

Dr Lewis believes this is the crux of the problem – the fact that people choose to have the injections without considering that they could have an impact on their feelings.

Like many in the medical community, he believes more research needs to be carried out in this area.

kathryn@maltanet.net