People with a mental health disorder are more likely to marry someone with a similar condition than look for a partner without one, intriguing new research has suggested. Studies have shown that married couple are likely to be diagnosed with same mental illness.
A study of nearly 15 million people across Europe and Asia found that individuals with a psychiatric disorder such as depression are more likely to look for someone with similar mental health issues than a spouse without them.
The trend, identified by US researchers, appeared to be consistent across cultures and generations—for a range of psychiatric conditions—suggesting that it is a core pillar of human relationships.
The sweeping study, published in the journal Nature Human Behaviour, looked at nine different disorders including schizophrenia, bipolar, depression, anxiety, attention-deficit hyperactivity disorder (ADHD), autism, obsessive-compulsive disorder (OCD), substance abuse and anorexia nervosa.
Drawing on data from more than 14.8million people in Taiwan, Denmark and Sweden, making it one of the largest studies of its kind, researchers found not only were people with psychiatric conditions more likely to marry someone with similar health issues, they were also more likely to share the same disorder.
Interestingly, the researchers also noted that children with two parents who suffered from the same mental health condition were more than twice as likely to develop the same disorder in later life, in comparison to those with only one affected parent.
This was particularly true of children to parents with schizophrenia, depression, bipolar disorder, and substance use disorders—conditions where genetics are thought to play a significant role.
Professor Chun Chieh Fan from the Laureate Institute for Brain Research and lead author, said: ‘The main result is that the pattern holds across countries, across cultures, and of course, generations.’
The study looked at people born in the 1930s all the way through to the 1990s.
And whilst it was observational, meaning the researchers could not definitively explain why this pattern has evolved, three main explanations emerged.
Firstly researchers suggested that people tend to be drawn to friends and romantic partners who resemble themselves—perhaps because similar life experiences fosters deeper understanding and empathy.
It has also been theorized that couples grow more similar over time, through shared environments—a phenomenon known as convergence.
Finally, researchers highlighted that the existing social stigma around mental illness may significantly narrow the dating pool for people with psychiatric disorders, subtly shaping marriage choices.
The 5 million spousal pairs from Taiwan were matched with estimates from the Danish national registry and results from the Swedish national registry suggesting that the phenomenon is not driven predominantly by culture.
Latest statistics show that the number of people seeking help for mental illness has surged by two fifths since before the pandemic, reaching almost 4 million.
An estimated 2.5 million people in England alone are thought to be living with ADHD, according to NHS analysis.
Common symptoms include restlessness, distractibility, forgetfulness, difficulty following instructions and managing time, and making impulsive decisions.
ADHD’s exact cause is unclear but is thought to involve genetic mutations that affect a person’s brain function and structure—although many experts have linked it to environmental factors such as diet.
Meanwhile, the latest figures from the Office of National Statistics (ONS) show almost a quarter of children in England now have a ‘probable mental disorder’—up from one in five in the previous year.
Last year, NHS England said it was treating 55 per cent more under-18s that before the pandemic.
Youngsters from all economic backgrounds have suffered setbacks to their emotional and social development since lockdown, researchers have found.
