ADHD or learned behaviors

My 4 year old son, has for the past 2 months been really out of control, hyper, throwing items, cussing. I am puzzled because he's been a really good listener, and usually gets very upset when my husband or I discipline him. Now, he laughs at us. The interesting part in this scenario is that my 10 year old has ADHD, oppositional defiant disorder, Bi-polar. I've been dealing with some pretty serious behavioral problems with the 10 year old, same behaviors, yelling, screaming, throwing items, very hyper. I'm bringing the 4 year old to be evaluated, but since this came on so sudden, do you think it is related to 10 year old brother's behavior?

[Kevin Kennedy, Ph.D.]

Dear Kathy,

It's unlikely your son's behavior reflects any neurobehavioral condition, such as ADHD. The sudden onset really doesn't support the likelihood of ADHD. His behavior in all probability reflects an adjustment disorder secondary to the family strains associated with your older son.