My ds12 is 2e - I don't know that it's decision making that fatigues him, but definitely can see that he spends so much energy during the day at school that he's exhausted far beyond what my nt kids are at the end of each school day. In his case, part of the exhaustion is the mental effort it takes to get through the academic challenges he has (written expression, expressive language), and another large part of it is boredom and frustration due to the pace of most of his classes - so definitely a combo of his challenge and his giftedness.
polarbear
