Australian researchers believe that mental well-being and illnesses such as depression or anxiety are separate constructs. They came to this conclusion after testing the processing of emotions in twins.
Health is the state of physical, mental, and social well-being and not just the absence of disease or infirmity. At least, that is how the WHO sees it, which enshrined this definition so similarly in its constitution 70 years ago. The same applies to mental health. Some scientists believe that mental disorders and mental health may even be two largely separate constructs. The twin study (1) by Kylie Routledge of the Brain Dynamics Center of the University of Sydney and her colleagues now supports this hypothesis.
Although there is more and more research on mental health, it is still not quite clear what neuropsychological mechanisms are behind mental well-being. One form of neuropsychological processing that is known to be the most important for mental health is the processing of emotions. Difficulties in the processing of emotions, on the other hand, are a sign of mood disorders. Various studies, for example, have a connection between faulty processing of emotional facial expressions and diseases such as schizophrenia, depression, or attention disorder ADHD.
Normally, people intuitively recognize the mood of their counterparts by their facial expressions, because so-called basic emotions such as joy, surprise, anger, grief, disgust, or fear become noticeable in all cultures through the same facial expressions. Some areas in our brain recognize the emotional state by the facial expression, while others help us to put ourselves into the feelings of others. Scientists around Routledge tried to use facial recognition to find out how much psychological well-being, depression, and anxiety are related at the genetic level. For this, they examined 1668 twins between the ages of 18 and 62.
Twins are a popular object of study for such questions. As a rule, they grow up together in the same environment. However, they differ in terms of their genes. While monozygotic twins are genetically almost identical, the genetic make-up of dizygotic (fraternal) twins is only about 50 percent identical. Therefore, if identical twins show greater similarity in a trait than fraternal twins, it is assumed that genetic factors are responsible for this.
For this study, the twins were shown pictures of faces for two seconds, among other things. They were then asked to decide whether to read happiness, fear, anger, sadness, disgust, or neutrality in the facial expressions. The twins were also asked about their state of mind to see who showed signs of depression or anxiety or who was doing very well. Then, these responses were evaluated.
In the researchers’ study, a high degree of well-being was associated with faster reaction times in happy faces. The more depressive or anxious symptoms the subjects themselves showed, the slower they reacted to the happy facial expressions. However, the researchers only found a genetic connection between depressive and anxious symptoms. They saw that twins with anxious or depressive symptoms also identified neutral emotions less quickly. This time, however, they found no explanation at the gene level.
The scientists see their hypothesis as an indicator that psychological well-being, depression, and anxiety are largely independent from the ability to process emotions at the behavioral level, as strengthened by these results. However, they point out that they have only worked with healthy twins. Therefore, their theory should also be tested on twins who actually suffer from depression or anxiety. It would also be interesting to know if the same results would be obtained by investigating emotion processing with other methods.
- Routledge KM, Williams LM, Harris AWF, Schofield PR, Clark CR, Gatt JM. Genetic correlations between wellbeing, depression and anxiety symptoms and behavioral responses to the emotional faces task in healthy twins. Psychiatry Res. 2018 Jun;264:385-393.
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