The role attributed to mental disorders ultimately depends on the guiding aims of penal law. Justice may be understood as the establishment of guilt or as some form of equalling out wrongs, whereas modern penal systems serve several, partly conflicting, goals. If retribution is the goal, reduced accountability due to mental disorder must be considered as humans have unequal chances of refraining from crime (Rhee & Waldman, 2002). If the goal instead is crime prevention (through treatment, incapacitation, deterrence, or combinations thereof), sanctions have to be devised in relation to the risk of criminal recidivism and their scientifically documented, preventive effect.
Factors that would be considered mitigating in the context of retribution (such as youth, poor social integration, impulsivity, deficits in other mental faculties) may instead call for harsher preventive measures, such as long-term incarceration or intensive societal surveillance.
Every attempt at implementing a purposeful societal approach to criminal offenders would thus require a clearly stated aim, or combination of aims, for the penal law. If the legislator wants the system to fulfil several aims, it has to be clearly stated what these aims are and what their relative priorities should be when conflicts ensue. No system could fully serve each and every aim.
The lawyer’s perspective is focused on the procedures of the judicial process. In the individual case, the causal role of a mental disorder behind a crime has to be determined, and the normal requirements of justice, such as equality, predictability, and transparency, have to be upheld. Lawyers must know what expertise to ask for and exactly what type of knowledge the different experts can provide. They must also be familiar with the grounds for questioning expert opinions and seek a second view, or with how to challenge a testimony presented in the courtroom.
At the end of the day, it is also lawyers who will have to evaluate the causal relation between the psychiatric problems diagnosed and the crime committed. “Beyond any reasonable doubt”, the normal standard of certainty in law, has to be accommodated to the lesser precision of the clinical judgment of psychiatrists.
This blog post is partly excerpted from the paper "Mental disorder is a cause of crime" I co-authored with Susanna Radovic, Christer Svennerlind, Pontus Höglund and Filip Radovic in 2009.