My DD2 (just turned 4)has had CO since being 6 weeks, she was such an unhappy baby, after the first treatment she was more settled and got a little better after each treatment.
She hadn't had any CO for 18 months because we couldn't afford and we've had horrendous problems, she's always whingy, her behaviour can be aggressive, she's very frustrated etc. To cut along story short after seeing the health visitor regularly and being brushed off, we finally got refered for eyes, speech and hearing and a padeatrician.
Also after seeing our GP's we've finally found one who would refer us to a CO (for private treatment so medical insurance would pay for it).
The CO is now helping as my DD2 has calmed down and alot of her 'minor problems' (as the nhs officals call them) seem to be related to her skull problems.
The CO has confirmed this and the speech therapist (who finally has agreed that my DD2 has got some problems which will cause her problems in school etc) has said that although CO is not recognised by medical profession it can work and if I see the results then go with it.
As an aside to this, many years ago I had a bad car accident and couldn't move my neck for 4 months (even though I was having regular physio). After one treatment with an osteopath my neck was completely moveable and I continued to have treatment until it was totally mobile going forward. This is just personal evidence that osteopathy works.