We have totally struggled with ds1's behaviour/difficulties since he was about two years old.
I tried to seek help via the GP, but was always just fobbed off. The school referred him to CAMHS when he was in Reception Year because he was so awful. School were given a support worker and ds1 eventually learned how to behave in school, but we continued to struggle at home.
When he was nine I had him assessed privately and was told he did have adhd, but was coping well, so only parenting strategies were recommended.
Saw CAMHS again last year after a second attempt to get help from them and they said that he doesn't have adhd, was showing some signs of aspergers, but didn't want to assess him for aspergers 
He is now 12 and continues to struggle with social relationships and life in general. His intellect and school attainment is very good and he's bright.
Some of the things he does are:
Talk non stop about his favourite subject, history
Doesn't seem to understand that we can't cope with endless talking
Soils himself if he goes into the bath - has to have showers
Makes silly noises
Talks extremely loudly
Sings to himself and has to make a noise all the time
Needs to stick to an expected routine
Struggles if this routine is deviated from
Asks questions all the time about how long things are going to take and what time it will happen
Is obsessed with buses, esp. the bus that he gets to school each day
Is very immature in his general behaviour, but quite mature about his school subjects, religion, politics etc.
Terrified of new social situations and just doesn't 'fit in'
I have read about the characteristics of aspergers and much of his behaviour fits. He can make eye contact with me, but struggles with people that he doesn't know. He does have some empathy with others, but this is mostly superficial.
His adhd symptoms appear to be either diminishing or are becoming more manageable, but the other problems persist and I'm worried that he does have aspergers.
We receive absolutely no help/support and I'm worried about ds1 because he came home from school on Friday to say that his friendships at his new school are breaking down and only two people in his tutor group are speaking to him now. I think he may have upset some people because he's a real wind up merchant and is generally irritating and 'difficult'.
How can we get CAMHS to take us seriously? They just fob us off and say it's a parenting issue, but our parenting has been assessed and it's been deemed fine and also ds2 is completely normal and doing well.
ds1 is just 'odd', but how can we get them to see it?