Comment by kosma

There is research correlating autism and mothers taking certain medications (painkillers, antidepressants). Since autism is hereditary, there is a significant chance that these mothers are autistic too. Autistic people have a vastly high risk of depression, and often have unusual pain thresholds, requiring more painkillers. I would not be surprised of the correlation was real, but the direction of action was reversed; after all, it's plausible that autism causes the need for taking more medication.