~2.8% of the population has bipolar disorder. The odds that one partner at the start of a relationship is bipolar should be ~5.6%. 1% of the population is schizophrenic so ~2% of the population. We aren’t quite up to 7.6% of relationships just from those 2 groups because there’s overlap but it does stack.
Granted I haven’t done the research to pin down exact numbers but higher rates of divorce operates in both directions. So stable couples are healthier than average and divorced couples are worse than average.
Still something like 16-25% of the overall population has some form of diagnosable mental illness, couples have 2 people, and divorced are more likely to have various conditions. So the effect size would need to be huge for this not to be relevant.
Most studies agree that bipolar disorder is not evenly distributed across the sexes. Schizophrenia is roughly equal but occurs for men before/during peak childbearing years, and for women happens after.
I don’t think that actually impacts the statistics here the way you think it would.
Suppose 2% of the population had X. If 1% of women had X, ~3% of men would have X and therefore ~4% of couples would.
Age of onset, differences in rates of relationships, etc are all worth considering. But my point was simply it’s significant not that I had calculated some exact number. With divorced people having the possibility of remarrying simple calculations aren’t enough.
is that really a significant factor? i'd think that the number of people suffering from mental issues is a minority, and even if in their group are more divorces, those should only be a fraction of the total number of divorces.