Well, there are lots of possibilities. "For most disorders, the chances of partners sharing a diagnosis increased slightly with each decade, particularly for t

Well, there are lots of possibilities. "For most disorders, the chances of partners sharing a diagnosis increased slightly with each decade, particularly for those with disorders related to substance use." "Although the study did not investigate what causes the phenomenon, Fan says three theories could help to explain it. First, people might be attracted to those who resemble them. 'Perhaps they better understand each other due to shared suffering, so they attract each other,' he says. Second, a shared environment could make partners more alike — a process known as convergence. And third, the societal stigma of having a psychiatric disorder narrows a person’s choice of spouse."