Idiopathic autism has been on the rise in recent years and is thought to be caused by a mixture of genetic risk factors as well as some as yet unknown environmental factors. Research suggests a link between antidepressant use by pregnant women and the development of autism. Further, some unmetabolized psychoactive pharmaceuticals (UPPs) have made their way into drinking water from sources at the surface posing a potential environmental risk of exposure. To study the potential link between UPPs and autism, Drs. Michael Thomas and Rebecca Klaper exposed fathead minnows to a mixture of three psychoactive pharmaceuticals at doses similar to the highest levels found in the environment:
1. fluoxetine (i.e. Prozac) – antidepressant
2. venlafaxine (i.e. Effexor) – antidepressant
3. carbamazepine (i.e. Carbatrol, Epitol, Equetro, Tegretol) – anticonvulsant used to treat seizures
They then analyzed gene expression levels between animals exposed to either individual or combined pharmaceuticals and compared the results with genes involved in ten different human neurological disorders. What they found was that genes associated with idiopathic autism were enriched. These results suggest that environmental sources of UPPs induce gene expression patterns in minnows that are similar to autism in humans. Further work is needed to determine if idiopathic autism in humans may be attributed to similar enviromental contaminants.
Thomas MA, Klaper RD (2012) Psychoactive Pharmaceuticals Induce Fish Gene Expression Profiles Associated with Human Idiopathic Autism. PLoS ONE 7(6): e32917. doi:10.1371/journal.pone.0032917