Forensic Psychology articles

Illustration by Mark Alan Stamaty.

When someone commits a horrific, inexplicable crime, we naturally wonder whether he’s mentally ill: Who but a crazy person could do such a thing? But when a killer acts crazy after his arrest, we also might wonder whether he’s preparing for his trial. That’s the speculation around Colorado shooter James Holmes, whose psychiatric treatment and bizarre behavior in court and prison make people wonder whether he’s truly insane or building a case for an insanity defense. It leads to the question: Can a criminal get away with faking insanity?

Experts have been debating that question since the creation of the insanity defense in the mid-19th century. To avoid the noose or the guillotine, criminals of the era would fake symptoms from the then-emerging field of psychology. It soon became a cat-and-mouse game: Criminals would act out their understanding of insane behaviors, and alienists (the era’s term for psychologists) would write studies on how to detect those “malingerers.” Most techniques relied on the investigators’ experience and powers of observation—looking for inconsistencies in symptoms, waiting until the suspect tired of the game, or simply catching a telltale look in his eye. As the Austrian criminologist Hans Gross wrote: “The shammer, when he thinks no one is looking, casts a swift and scrutinizing glance on the Investigating Officer to see whether or not he believes him.”

Today, less than 1 percent of felony defendants raise an insanity defense, and a tiny fraction of those succeed. Yet in a state like Colorado, where proving insanity can avert a death sentence, the temptation to appear mentally ill must be strong. And so modern forensic psychologists, just like their forebears, watch for malingering with a sharp clinical eye. They determine whether the symptoms match those of well-studied pathologies and whether the signs remain consistent over time. They also can apply a battery of tests that essentially fake-out the faker.

The first step is to do a thorough review of the suspect’s history. Mental illness doesn’t develop overnight, so it’s important to know if the person has been hospitalized or treated for similar symptoms. The investigators also review the crime-scene report. If the suspect has hidden the weapon, washed off his fingerprints, or taken other steps to elude the police, it’s a sign of clear thinking—not mental illness.