I should probably give you a few more details so that you get a better understanding of the situation. My nephew had quite a difficult birth - long labour, cord round his neck, forceps and needed resuscitation at birth. He was quite a demanding baby - never slept for long, wanted to breastfeed almost every hour and always quite clingy towards my sister. As a toddler, he was a late talker, although an early walker and out of nappies day and night at age 2 and a half. My sister had her dd when he was 22 months.
He has always found it difficult to get along with other children, used to hit out at toddler groups and continued to when he started playschool. Has never been very good in group situations, but on a one-to-one is great. He is now at his 3rd school, the first move was because my sister moved to a different area. At the 2nd school, he continued to have problems and the teachers really could not handle him, which was a shame as it was an excellent school. Now, he is in a private school. Academically, he is brilliant, reads and writes very well for his age, although sometimes he is too clever for his own good, if you know what I mean, and will answer teachers back with almost adult-like reasoning and confidence. He has never really had many friends, my sister says he seems quite awkward in the company of other children, and that they seem scared of him.
I know that I am being long-winded about this, but I just wanted to set the scene a bit. In a nutshell, his problems are: he has quite a temper on him, very competitive and doesn't have much patience with those who can't match him, can be aggressive towards other children sometimes for no apparent reason, can be disrespectful to teachers and other adults, usually in the form of answering back or arguing with them.
As I said before, there really doesn't seem to be any obvious reason for his behaviour. My sister and her dh have made a real effort with him, and tried many different approaches, but really to no avail, so you can see how she is beginning to despair. We all know that at 6, he is still quite young, and most teachers say that he will grow out of it, but anyone who has been in this situation knows that it doesn't really help you in the meantime. I really feel for my sister, and I know to an extent how she feels, as I had problems (although different ones to my nephews) with my eldest ds at playschool, though now he is in full-time school, he is doing great. I really don't know what I can suggest for my sister to try which is why I turned to Mumsnet. I don't think that I found a miracle cure for my ds that I can pass on to her, rather that I was lucky to find the right school for my ds where he is settled and happy. It is really frustrating as we know that he can have a sweet, loving and vulnerable side, but can't understand why he persistently does things that he knows are wrong. So you see, my sister is worried that she may be missing something which is obvious to an expert, but would prefer to find the help by herself at this stage. The school he is at now have not mentioned an educational psychologist, but the school he was at before did. Really, my sister has thought about him seeing one as she, dh and the rest of the family have tried everything else but nothing seems to be working.
Thanks for your comments so far. I have just written this as it's come into my head and as I remember what my sister has told me, so I hope it makes some sense. Any further comments/ideas very welcome.