A steady decline in insanity claims by defendants in criminal cases over time juxtaposes with a concurrent increase in claims that defendants are "malingering" or "feigning" insanity or mental illness in the service of an acquittal or a reduced sentence. Neuroscientific evidence, on both sides, features prominently in these trends. And in this setting, conventional wisdom implies that state evidence introduced relating to a claim of defendant malingering may exert out-sized (negative) influence on a defendant's insanity claim.
A recent paper, An Empirical Study of Malingering in Insanity Cases Across Twelve Decades, reports results of an effort to submit this conventional wisdom to data. In the paper, Deborah Denno (Fordham) levers "all criminal cases" (N=8,335) that engage with neuroscientifc evidence, with a focus on a subset of insanity cases (N=3,108) that include malingering claims from 1900--2020. What the paper finds largely comports with conventional wisdom and emphasizes that assertions of defendant malingering are among "the strongest prosecutors can make to rebut" a defendant's insanity claims. The paper also emphasizes how malingering evidence can lead to "highly detrimental outcomes" for defendants.