In the study, participants from Taiwan, Denmark, and Sweden were divided into age cohorts from the 1930s to the 1990s. Researchers assessed the spouses' prevalence of one of nine mental disorders: schizophrenia, bipolar disorder, depression, anxiety disorder, attention deficit hyperactivity disorder, autism, obsessive-compulsive disorder, anorexia nervosa, and substance use disorder.
It turned out that people with a mental disorder were more likely to marry a partner with the same disorder than those without, Nature reports . The overwhelming majority of spouses had the same diagnosis, but in some cases, people had different diagnoses from the aforementioned list.
"The key finding is that this pattern persists across countries, cultures, and generations. Even changes in mental health care over the past 50 years have not reversed this trend," said study co-author Chun Chieh Fan.
Notably, only obsessive-compulsive disorder, bipolar disorder, and anorexia nervosa showed differences across countries. For example, couples in Taiwan were more likely to suffer from OCD than couples in Northern European countries.
Additionally, for most disorders, the likelihood of partners having the same diagnosis increased slightly with each decade, particularly for those with substance use disorders.
According to Jan Fullerton, a psychiatric geneticist at the University of New South Wales in Sydney, social and environmental stressors may contribute to a new diagnosis in a previously healthy partner, especially if they previously had milder, undiagnosed symptoms. Clearly, scientists need to conduct further research to understand the reasons for this trend. The findings could potentially improve prevention of mental disorders.
In another study, researchers previously found that one spouse's happiness reduces the other's stress levels. It turns out that one person's positive emotions help the other cope with stress without any additional effort.
