Our 9 year old LFA did that back when he was 4 and 5, and treating for yeast did help, I think. He went GFCF and we gave him probiotics, especially sacchromyces boulardi (sp?). Also ground flax seed in his GFCF waffles.
He hasn't done the hysterical laughter too much lately, about once very month or two, and he usually only wakes up in the night for a few hours once a week or so, more if he's having a gut flare up. He can now tolerate casein, so we just have him GF, although he refuses milk and only eats small amounts of cheese, but we put powdered milk in his GF pizza dough.