IQ testing while on meds in Atkins MR death penalty cases: Pruitt v Indiana (2005, 2007) court decision

A new twist in Atkins MR death penalty issues...courtesy of Kevin Foley (thanks again).  Pruitt v Indiana (2005) and again in 2009 (now posted in the Court Decisions blog sidebar).  Below I paraphrase some of the questions raised by this case.  What do readers think? 

In 2005, the Indiana Supreme Court upheld the trial courts original death penalty decision.  The interesting twist is that a defense expert testified "that he believed Pruitt was under the influence of the antipsychotic medication Trilifon at the time he took the test and the medication superficially increased his ability, resulting in an over-estimation in that test by three to six points. Pruitt argues that the testimony of Dr. Golden and the medical literature both support this conclusion." (p.11). Pruitt obtained a WAIS full scale IQ 76. In 2009 the court again reaffirmed the death penalty sentence.

Of interest is a relatively recent (2007) AMA journal study (Archives of General Psychiatry), by the Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE) research group, re: the efficacy of antipsychotic medications.  The study examined the cognitive benefits of different medications including perphenazine (Trilafon). The battery of mental tests did not include a full IQ test, but instead a "neurocognitve" composite comprised of  measures of processing speed, reasoning, working memory, verbal memory, and vigilance.  The subjects (n=149) on perphenazine showed a statistically significant .25 standard deviation (SD) improvement (after two months) in their composite score.  A .25 SD z-score improvement translates to an IQ score change (when on a scale of Mean = 100; SD = 15) of 3.75 (roughly 3-4 IQ points).  After 18 months, n=52 of the subjects were again assessed and the SD change from baseline (prior to initiation of medication) was approximately .50 (.49).  On a standard IQ test, this would convert to an increase in IQ scores of approximately 7-8 points (7.5).

So...was the defense experts claim of an inflated IQ score (due to meds) appropriate...and thus Pruitt should have been ruled to be a person with MR/ID?  Or, should one argue that "you can't have your cake and eat it too" ---- that is, claim you cannot be tested when grossly psychotic (and thus not competent to be executed) and then turn around and discount improved cognitive testing when on medication?

Other related questions to ponder:

• If a person is functionally retarded (poor cognitive "performance" in the real world) at the time of the crime (due to psychosis), and later, when properly medicated post-crime and tested, obtain IQ scores suggesting higher non-MR cognitive functioning, what should be the decision regarding MR as per Atkins cases?

• If the defense expert's arguements had swayed the court, would this open the proverbial "slippery slope?" What about all the other medications used in prisons to address prisoner needs and/or behavior (e.g., stimulants for ADHD; meds to help with sleep; etc.).

• Of course, this type of case raises the whole complex set of issues of dual diagnosis and which is the primary/secondary diagnostic condition.

Of course, there are all other kinds of "it depends" issues (standard error of measurement, etc.).  Lets put them all aside and pretend they don't exist or have been accounted for.

Thoughts?  Reactions?  Comments? 

Have you taken your meds today?

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