I beg to differ from the first responder. There certainly are early signs of ADHD but the problem is that they can mimic the signs of a lot of other things including just being part of the child's natural temperament. So while I was experiencing my daughter's EXTREMELY challenging toddler, threes and fours...I had no idea that these were early red flags. But now you can benefit from my hindsight!
My daughter started going through what we thought were the terrible twos early--around 18 mos. she started having EXTREME temper tantrums.
--She was extremely hard to soothe when upset.
--She would have tantrums over what seemed like the silliest things (low frustration tolerance--plays into school later on)
--She would get so out of control she would bite herself and pull out her own hair while tantrumming--I called them "rages."
--She had night terrors almost nightly, sometimes more than once starting just after she turned two until she was four. She still has them occasionally at almost 6.
--She never had stranger anxiety. She gets giddy and amped up in new situations. Jumps on people she just met, makes weird noises, doesn't listen--cannot stop or get control of herself.
--Sometimes she is hyperfocused on what she is doing and tunes out everything else. ADHD kids can focus on things they are interested in so just because she focuses on certain things does not mean anything. My daughter could NOT focus when I was trying to teach her the alphabet. She was twitching and jumping all over the place.
--At the school Xmas show, she was the only kid turning around and facing backwards, sideways, bothering kids next to her--doing anything but singing. In a spaced out kid, this might look like staring blankly off into space and not singing. And yet at home, she can belt out Tomorrow just as well as Annie herself.
I saw all of these things before she was diagnosed but since she was so young I thought it was all normal "young kid" behavior....and to an extent, some of it is. All kids misbehave, act out, have tantrums, run and jump, etc. but in young ADHD kids, it is EXTREME. If you are the parent leaving playdates crying like I was and wondering what the heck is wrong with your kid....well, it could be ADHD.
BUT, my daughter is extremely bright, social, outgoing, artistic, athletic. Her AHDH is tied into many of her strengths. In fact, on her second day of kindergarten last week, a teacher came up to me and said "I have to tell you, your daughter is EXTRAORDINARY...blah, blah, blah." I was so proud I could have popped. My daughter is either the best or the worst, but there is never a happy medium with our 6 year old ADHD spitfire.