Every time you turn around there is another study contradicting the last on antidepressant use and autism risk.  An answer on why there are differences across different studies may be found in a new analysis published by University of Washington and SSM Dean Medical Group in Wisconsin this week.  They showed that autism severity (not risk) is increased only with both a likely gene disruption AND following antidepressant exposure in pregnancy together.  This suggests a double hit model similar to other complex neuropsychiatric disorders like depression.  It also suggests that findings from other chemicals, like PBDE’s, may be dependent on gene / environment interactions too.  After all, a new systematic review showed PBDE’s during pregnancy are bad for the IQ of the child.  This provides insight on ASD risk and subtype given the multitude of possible genetic / environmental combinations out there.