Possibly. It may depend on the wirehead.
Heroin addicts sometimes engage in crime - but at other times, they are "on the nod" - and their danger level varies accordingly.
It seems quite possible to imagine a class of machine that loses motivation to do anything - once it has "adjusted" itself.
make that a large class of all possible optimizers.
Link: aleph.se/andart/archives/2011/02/why_we_should_fear_the_paperclipper.html