I think a number of antipsychotics can have body temperature regulation side effects. I don't recall having it with Risperdal, but we can experience some side effects on certain meds that others don't. The meds that most caused it in me were/are Seroquel and higher doses of Lamictal. When I was on them about 16 or so years ago, and even now. Hot weather did exacerbate it, as did anxiety. Nowadays maybe even perimenopause plays a part. At times it was even profuse sweating, made worse by anxiety about it. Drinking ice water/drinks helped.

Risperdal maybe caused me weight gain, but not nearly as much as some other APs. The main side effect I had on it was hyperprolactinemia, with lactation so bad that I had to put pantyliners in my bra. A more positive effect from this was breast enlargement, but as a woman who had smaller ones to start it was OK. It obviously isn't for men. Again, not everyone gets this, but it's not uncommon. Invega did the same in me. It didn't get that out of hand, though.