Insanity, Law, and the Pedophilic Brain Tumor

Given the subject of last month’s Journal Club meeting and the current poll, I wanted to take a moment to talk about issues of volition, cognitive impairment and impulse control in law, especially as they relate to sex offenses, and the way neuroscience research is beginning to impact these relationships. I am going to consider the following as a general question, rather than analyzing the details of the particular case:[1]

If a man is discovered to have committed sex crimes against children due to uncontrollable pedophilic urges, and those urges were proven to be caused by a brain tumor, is he guilty of his crimes?

As I write this, votes on the blog have “not guilty” beating “guilty” by 32 to 25. Honestly, the number of “not guilty” votes surprised me a bit, as there really isn’t a question about whether or not he committed the crimes. As I thought about it, I realized that perhaps for some the question of guilt isn’t whether he did it, but whether or not he should be held responsible, and then, if responsible, whether he should be punished. How we answer those questions depends on, one, our understanding of what it means to be responsible under the law, especially where neurological impairment is involved, two, what the purpose of punishment is, and three, the unique position of sex offenders, particularly pedophilic ones, within the United States. 
For most of us reading this poll, I am willing to bet that the question of this man’s responsibility comes down to a sense that he is probably legally insane. Insanity in the law is distinct from insanity in a psychiatric sense, in as much as legislators and judges are not held to psychiatric standards when creating law.[2] “Legal insanity” may refer to a declaration of: incompetence, not guilty by reason of mental disease or defect, or a danger to self and others. The first standard is used to determine whether someone can participate in legal proceedings, the second can be offered as a criminal defense, and the third is used as a standard for involuntary or civil commitment (sometimes called a psych hold or “sectioning”.) A declaration of incompetence or a civil commitment would apply if the tumor, or its removal, caused significant cognitive impairments beyond the uncontrollable urges. In either case, he might never be convicted of the crimes in question, and therefore would never be declared “guilty,” but would be subject to lifetime monitoring and/or institutionalization to prevent re-offending. Whether he would be eligible to plead not guilty by reason of insanity is more complicated. The definition of insanity in this portion of the law may mean cognitive, emotional, or behavioral impairment, depending not only on the type of offense and the context under which it was committed, but also the jurisdiction, the admissibility of scientific evidence, and the timeline of discovery.[3] (This fact alone sometimes makes mental health professionals, behavioral biologists and neuroscientists want to tear their collective hair out.)