Will Neuroscience and Law Collide?

On July 20, 2012, James Holmes, a recent neuroscience graduate student at the University of Colorado, opened fire inside a movie theater in Aurora, killing 12 people and injuring more than 70 others. Holmes had been diagnosed with schizophrenia, and was clearly psychotic. At his trial, however, the prosecuting attorney argued that the shooting was meticulous and premeditated, using as proof the fact that Holmes had booby-trapped his apartment. Eleven of the 12 jurors voted for the death penalty, arguing that he had acted rationally. Holmes successfully entered a plea of not guilty by reason of insanity, however, and was sentenced to 12 consecutive life sentences plus 3,318 years without parole.

The case illustrates some of the most difficult issues that have emerged in modern bioethics: Are people with mental illness competent to stand trial? Is it acceptable to administer anti-psychotic drugs to them without their consent, so that they may become more competent to do so? Is it ethical to withhold drug treatments so that they can participate in scientific research that might help researchers to gain a better understanding of their condition?

Steven Hyman

Cases such as this also illustrate how neuroscience and the law may be at odds with each other, said Steven Hyman, director of the Stanley Center for Psychiatric Research at the Broad Institute, a member of the Dana Alliance for Brain Initiatives and a member of the board of directors of the Dana Foundation.

“The most important thing here is the disjunction between the way we understand our decision-making and action as human beings versus the way we understand it in the laboratory,” said Hyman in his Max Cowan Special Lecture, which he delivered at the 10^th FENS Forum of Neuroscience in Copenhagen earlier this month. “Advances in neurotechnology and advances in our understanding of the brain as the organ of cognition, emotion, behavior, and the self raise important issues about morality and policy.”

Hyman noted the genetic and gray matter deficits implicated in schizophrenia, as well as the disturbances in thought processes these people have. For example, most of us experience a sense of agency, the sense that we are in control of, and responsible for, our actions. This sense arises largely as a result of neural processes that occur unconsciously. Agency is diminished when we are coerced into doing something, and is also reduced in schizophrenia, such that patients will misattribute their thoughts and actions to external forces. This partly explains the auditory and visual hallucinations that people with schizophrenia commonly experience–they are unable to distinguish between sensory stimuli that occur in the outside world from those that are generated internally.

“Psychotic symptoms wax and wane, but these things are private and invisible,” said Hyman. “Holmes may have planned his crime meticulously, but we don’t know whether he was being commanded by voices at the time, or if it was the result of a more rational process, and so it’s up to us to show that his rationality and volition were impaired.”

Similarly, one could argue that drug addicts are not always fully responsible for their actions. Addictive drugs hijack the brain circuitry involved in reward and motivation, and this leads to significant changes in social behavior. Initial exposure to an addictive substance increases dopamine concentrations in a brain structure called the nucleus accumbens–often referred to as the brain’s “reward center,” producing pleasurable effects. But continued exposure can lead to a maladaptive learning process that exaggerates its rewarding effects. Thus, there can be a gradual transition from voluntary to compulsive drug use, which leads to persistent and inappropriate actions that are often harmful to the addict. Some researchers now refer to addiction as “a disease of free will.” [See: How Should Society Treat Addiction?]

“Drug-seeking behaviors are consolidated into highly automatized habits that are independent of long-term goals and very like obsessive-compulsive disorder,” said Hyman. “Conscious volitional control is clearly subsumed by drug-taking behaviors that are exceedingly difficult to resist. What seems to be happening is that cognitive control is weakened in some way by chronic drug use, and this is something that warrants further investigation.”

Like patients with schizophrenia, however, drug addicts often paint a confusing picture to others around them. “They can engage in perfectly normal conversations with family members and physicians,” Hyman continued. “They look just like us and they sound rational, and therefore we attribute to them the same decisional control that we might have, but they don’t have that.”

Despite these advances in our understanding of how psychosis and addiction diminish free will, the way in which such individuals are treated within a criminal justice system is not likely to change anytime soon.

“This still isn’t ready for prime time, and courts of law are still not convinced,” Hyman concluded. “We have to find ways to make visible and salient the notion that these individuals have lost control of their actions because a whole set of neural processes has been undercut.”