I realized that I didn't really give enough detail about Riley's situation. It's sometimes so hard to put into words. To answer your questions-
1) What does the family mental health picture look like--any bipolar, anxiety, obsessive compulsive disorder, depression, etc.
I have a history of depression and anxiety. I also have an uncle who's schizophrenic.
2) We're so used to defiance and explosiveness here that it would be good for you to clarify. When you say defiant are you saying that he doesn't obey quickly and easily or that he has tantrums that bring the household to a complete standstill for a few hours? (I just thought to ask that remembering that when my best friend described her daughter as defiant it was to her but she was a cakewalk compared to the kids we often see through here)
I guess defiance and explosiveness can vary a lot. I didn't think of it that way. Riley is defiant to the point where it seems like he enjoys getting in trouble (laughing if he gets yelled at, etc.) He also seems like he is frantically looking for something bad to do. He sometimes talks back for no apparent reason "stupid mommy" "I hate you", things like that. As far as explosiveness, it's usually when he loses at a game, or his blocks fall down, or his sister gets into his stuff. All pretty trivial things as far as I can see. He will scream, cry, hit, kick, throw himself on the floor.
3) Are you noticing any quirky or unusual interests or behaviors, especially play behaviors?
I haven't really noticed anything like that, at least at this point.
4) Are you seeing any hypersensitivities to sensory stimuli like light, sound, easily irritated by fabrics, foods, etc?
He is very picky about tags in his clothes, but I can't think of much else.
5) The potty clogging issue is the sort of issue we frequently see in children with anxiety. Do you see that in him--fears of new places, things, severe separation anxiety, etc.?
Riley has always had noticable anxieties, which isn't too surprising, because I have a history of that. He is very shy around strangers, and is nervous when we go somewhere new, even if it's something fun like storytime at the library. He cried when I dropped him off at preschool all last year (luckily he's doing better this year). It's also funny because when I remember back to him as a baby, I could never take him in a public restroom because he would freak out over the sound of the flushing toilets.
6) Any speech delays or differences (such as adult sounding speech)?
His speech has always been very advanced, almost to the point where it seems odd. I'm not sure that I would call it adult-sounding per se, but he definitely uses big words that I don't hear other 4 year olds saying.