2E issues have definitely affected our son's IQ scores with either so much scatter the test isn't valid or with depressed scores that mask his Giftedness. But as master of none says, it really isn't a simple yes or no - there are so many factors that can affect the outcome.
As to treating without a diagnosis - what our psychiatrist has done is write a letter to include in his file that states that he is under observation and continued testing with no present diagnosis possible but with factors leaning towards the following - and then a list of possible diagnoses and a list of behaviors which need accommodations in the school setting. This has allowed us to get a better support system and environment in place without first slapping a label on him that may or may not be correct.
Good luck - it is a tough journey with no easy answers.
