It's great to keep custody of kids, and be thankful for them. I imagine it can be a great motivating factor.
Where do you get that statistic? What was the context of this stat?
I found this stat alarming, as it implies that most people with mental illness can't safely raise children. It takes some really serious danger for a child to be taken away from a parent, and that stat implies most people with mental illness can't ensure a child's basic safety. That's a serious claim. So I looked into the data on this a little more myself. I could not find anything that supported that 80% of parents with a mental illness lose custody, but I'd be interested in reading more about where this stat came from.
I did find other data that was encouraging.
According to WHO (World Health Organization), 1 in 4 people are affected by a mental health condition. (
http://www.who.int/whr/2001/media_centre/press_release/en/)
I found a study showed that for parents with severe mental illness, loss of contact or custody of children correlated with active substance abuse, and not actually mental illness. (
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2790143/) It was not a very big study, but it did give some interesting findings. I found other studies that indicated the same.
There is also a difference between mental illness generally, and severe mental illness. While 25% of the population has mental illness, only 4.1% has severe mental illness. Of those people, with SEVERE mental illness, about 50% lose custody at some point, and only about 12% percent are the primary caregivers. (
http://thefederalist.com/2015/07/29/what-happens-when-mentally-ill-people-have-children/) But that's for "severe" mental illness... This is defined in a lot of different ways, but it usually implies a GAF (Global Assessment of Functioning) score that is very low and is not the majority of people with a mental illness.
Overall, when we speak of all mental illness, about 1 in 6 parents have a mental illness but the vast majority are not losing custody of those kids because of that mental illness.
Link Removed (This was an Australian study)
I found this article to be the most interesting, written by an attorney about how parents can lose custody:
http://www.huffingtonpost.com/jacqueline-harounian/how-mothers-lose-custody_b_1140298.html
Being mentally ill and refusing to get help, along with many other factors, can be a path to lose custody in a contested divorce setting, but that's different than saying that 80% of parents with a mental illness lose custody of their kids generally.