Mood disorders appear to be much more common among the relatives of autistic children than among the relatives of other children. A survey article about this appeared in 2004. Here is a bit of the data:
In North Carolina, between 1988 and 1990, we studied 40 autistic individuals (20 attributable to known neurological disease and 20 idiopathic). Family histories, using the family history method, without knowledge of the neurological status, showed a low incidence of major mood disorder in the neurological patients (only two had family members with major depression, none with bipolar disorder). In the idiopathic autistic patients, by contrast, major depression was found in 14 and bipolar disorder in 8 of twenty families.
Between 1995 and 2002, we acquired another series of patients included in our study of fluoxetine treatment for young autistic spectrum children. We determined family history data as before and sought information about family members with special intellectual abilities or attainments, inspired by observing such individuals in many of the families. The abilities most often were scientific, mathematical, or computational but included others (e.g., professor of philosophy, professional musician). Analysis revealed a strong correlation among three groups: autistic probands responding to fluoxetine, family members with major mood disorder (especially bipolar disorder), and family members with special intellectual abilities. In this study, history of major mood disorder (in first- and second-degree parental relatives) was assessed in 151 families. One hundred and eleven families (74%) had a history of major depression (in 102) and/or bipolar disorder (in 52).
In other words, mood disorders were more common among the relatives of autistic children who responded to fluoxetine (Prozac) than among the relatives of autistic children who did not respond to fluoxetine. I have wondered why autism seems to be increasing. This linkage suggests it may have something to do with the long-term increase in depression.
Thanks to A Room of One’s Own.
Always happy to be of assistance. I find the research fascinating because, of course, there is a history of mood disorders and autism in our own family.
I can’t help but think that associative mating is part of what is going on with the rise in autism. In the old days “nerdy” girls and boys didn’t find each other to mate, but as this becomes more prevalent, we see a rise in autism.
The assortative mating explanation of the rise in autism has been proposed by Simon Baron-Cohen, an autism expert. It predicts that something else — whatever you get when you put two non-autism genes together — should also be increasing.
There’s a very famous ethnic Chinese math prodigy, out of three children in his family, he is a math genius, one brother is extremely bright, the third is autistic, apparently. Autism may be price that has to be paid to produce certain types of genius. I’d put most of the smartest people I’ve known somewhere on the “autistic spectrum”.
God evidence exists for the theory that vitamin D deficiency is responsible for autism. Since vitamin D deficiency is also linked to depression, the correlation described above makes sense. https://mangans.blogspot.com/2007/10/asthma-diabetes-autism-and-vitamin-d.html
What about the idea that autism and mood disorders might be increasing because they are related to problems in the birth process, and deaths from these problems have dropped dramatically. Over the twentieth century there was a drop in infant mortality from about 100 per 1000 live births in the beginning of the century to about 7 per 1000 in 2000. Some research has shown autism being linked to using antibiotics and not breastfeeding. People with autism may have benefited more from improvements in antibiotics and formula. I think this makes a lot of logical sense, but has the problem of being counter-intuitive. Greater health leading to more people with disorders!
One of my 2 year old students has recently been diagnosed as having the Autism Syndrome Disorder. The parents of the child mentioned that Bipolar Disorder has been diagnosed in the case of several of this child’s relatives. It is also very interesting that these relatives have very high IQs and the child is quite bright, inspite of his autistic tendencies.
My previous comment contained an error:
Autism Syndrome Disorder. The correct term is Autism Spectrum Disorder.