Is the Aurora, Colorado shooter James Holmes faking mental illness?

Obviously shooting a movie theater full of strangers is depraved and not normal.  But legal insanity means (generally) being unable to tell wrong from right.  The burden is on the accused shooter to do so if he uses insanity as a defense.  As a neurology graduate student, the shooter is familiar with the clinical standards for insanity.  Which raises the question on whether his recent behavior is being done intentionally to help an insanity defense.  His body language seems feigned.

He stayed silent throughout the appearance at Arapahoe County Court and at times appeared as if he was under heavy medication.But a jail employee has claimed that the 12-minute catatonic appearance was an act, not the result of any drugs.'We don’t just hand out meds,' the Arapahoe County Detention Center worker told the New York Daily News. 'It just doesn’t work like that. If he was acting sleepy, he was faking it.

There is also being able to reasonably assist defense counsel.  If the shooter is found mentally unable to do so, the court may delay the trial until he is well enough to assist (and could even force him to treatment and to take medication to gain lucidity).  

Update:  Shooter sent University psychiatrist details of this attack in advance?    Unfortunately it appears it was not opened or delivered (the police just found it).