I think we call this cranial osteopathy in the UK - if so I took my LO when he was about 8/9 weeks. Constant screaming drove me to try anything along with starting reflux meds, cutting out dairy from my diet, colic meds etc. Although I didn't really believe in it I figured I had nothing to lose and the lactation consultant who snipped my LO's tongue tie had suggested it.
All i know is that after the first session my LO took his first day time nap in weeks and the constant screaming was loads better. It might have been coincidence as I'd changed so many things but i think it helped. The woman I saw was great, i'd been really worried I'd get someone who would try and get me to sign up to weekly treatments for the next year or something but she was up front and said she couldn't guarantee it would help, but from her initial assessment she thought there were a few areas to work on and if we didn't notice a difference after 1-2 sessions we didn't need to keep going back.
I think it may've been easier at a younger age as the skull is less fused but I'm definitely pleased i gave it a shot. my LO has been a much happier baby ever since (he's now 10 months), i think he had about 6 sessions in total ending when he was about 3 months...
HTH x