problem with smearing

My son had a problem with smearing feces for about five months the summer that he turned two.  When put down for naptime, he would deficate and smear it on anything within reach of his arm.  I finally resorted to putting him exclusively in one-pieces outfits until I was sure that the habit had been forgotten.

Now, at six, he has a problem with smearing whatever he can get his hands on when he is left alone for a period of time.  One day he was supposed to be having afternoon rest time.  Instead, he went and got the toothpaste and smeared it all over the furniture, walls, mirror, etc..  Several incidents have involved lotion (his little brother has eczema and needs lotion at easy access locations).  Once it was the diaper ointment.  These days, it occurs mostly when he is supposed to be asleep at night.

This seems to be a much bigger problem in the fall months.  It is at this time of year that I began to really worry about the possibility of ADD.  He can't seem to focus on anything.  He also has sleep problems year-round, but again, they seem to be worse this time of year.  I don't know if it is related or not.  My doctor doesn't seem to take any of this seriously, but I am completely at a loss as to what to do!

Please tell me if you have ever seen this problem before.  Do you have any idea what might be going on?  What kind of help should I seek.  My son comes from a happy two-parent home with minimal stresses.  Chemical imbalances do run in my family, however.

Please help!