Dear Brian,
 
  I just read an article in Questions and Answers in October and there was a question regarding Kadabra and confusion. You said that when Kadabra was confused and did damage to itself it would do 40 because of weakness to psychic, like itself. So if my Aerodactyl was confused and did damage to itself would it do 0 damage because it has resistance to its own type?
 
Matt.   

Yeppers.  The clause in confusion states the Pokemon will deal 20 damage to itself - plain and simple.  It makes no reference to not applying weakness and resistence.  This is why a Kadabra boots itself in the head for 40, and the same reason why an Aerodactyl will shrug off his own attack. 

Scott