a question :
# since how long is your child going to the nursery ?
He joined in April last year.
That would be one year,
# Is he a single Child @ Home ?
# is he not interacting much with children's in the neighborhood ?
Well before taking him to child pshycologist.
Do take him to garden for a few days, let him mix with other children of is age. (do keep a close eye on him - coz kids do fight) :)
Mixing with other children as a behavioral trait, will help boost his confidence,
Take him to kids workshops, marathons etc, let him interact, give him some time.
and the change will be noticeable.
Okay.. do not make decisions based on someone else's suggestions; if your kid is very normal at home and is not same in school then the problem is with the environment; so check what is the reason for his behavior in school, may be he is not comfortable with the teacher or not comfortable with other kids; He is a three or four years old kid, he may not be able to share what he is going to through in the school; check how much pressure he is getting from his teacher to finish the home work or class work; Kids go through lot of stress as well and we may not observer but now a days they are going through the peer pressure as well. Ex: if a kid is doing really good in the class room, teacher may like the kid and teacher may appreciate the kid in the class room and teacher may show that kid as an example; this comparison is not all good and it should not be. Every kid is different from each other.
So I sincerely suggest you to talk to teacher and ask the teacher to give the examples like , at what time he is not responding, how is his mood while you drop your kid at school and how he feeling when you go and pick-up, what is he doing as soon as comes from school to home, and what exactly he is doing before going to school. And if possible and if your kid's school has CC TVs, please go and watch the CC TVs and monitor what he is doing during the class. Again, after all this analysis all other factors are looking kid, and if you think a visit to Dr is needed, please go ahead; Dr may ask all these questions. I would strongly suggest you to listen to your Kid's HEART, do not be stressed too much and do not pass the stress to kids. If not international school go for a small road side school, KIDs are like birds. They have lot of bright future.
In case, if you see any behavioral issues, there are very best schools and institutions to handle and cure. And my strong suggestion, keep your kids away from Phones and tablets. They need to know technology but limit the exposure; may be 60 mins in a day. And make sure your kid enjoys the sun set and sun rise.
these are just my views, I may be wrong as well; at the end please do what your heart says; and God Bless you...