According to a major study published in Nature Human Behavior, people diagnosed with a psychiatric disorder are more likely to marry someone with the same or a similar condition.
Researchers analysed data from over five million couples across Taiwan, 571,534 couples in Denmark and 707,263 couples in Sweden to investigate whether psychiatric disorders are commonly shared between spouses. They focused on nine major disorders: depression, anxiety, substance use disorder, bipolar disorder, anorexia nervosa, autism, obsessive-compulsive disorder, schizophrenia and post-traumatic stress disorder.
The findings showed that spouses were more likely to share the same or similar psychiatric conditions than to have different ones. “The main result is that the pattern holds across countries, cultures and generations,” noted one of the study’s co-authors. This pattern has significant implications for future generations. Since both genetic factors and the mental health environment provided by parents influence psychiatric outcomes, children with two affected parents are at an increased risk. In fact, those with parents who share the same diagnosis often face double the risk compared to children with only one affected parent. This can lead to earlier onset, more severe symptoms or the presence of multiple mental health conditions.
One explanation for these findings is assortative mating—the tendency for individuals to choose partners with similar traits and life experiences, including mental health histories. Other contributing factors may include shared environments, similar attachment styles and social identity dynamics that foster connection and mutual understanding.
“These results highlight how non-random mating influences the prevalence, inheritance and co-occurrence of psychiatric conditions,” the study concluded.