I'm not sure if this helps or is what you are looking for - but social factors of immediate and distal relevance would be taken into account. The social context at the time of the alleged offence that may have had a precipitating influence, or that may have either encouraged or failed to discourage the deed, as well as early social experiences. The availability of weapons in the environment is also crucial (e.g. access to a firearm in the case of a child/adolescent who is experiencing conflict with peers). I testified in a case recently of a child who had no history of behaviour problems, but found a firearm in his home which he used to shoot a school bully. Poverty & social support also play a role. We had a case a few years ago of a desperately poor young woman who came with her infant child  from a neighbouring country in search of work, but found that nobody wanted to employ her because she had a child to look after (and no other social or family support). She subsequently killed her child so she could get employment & send money home to her poverty stricken family.     

"There is a close relationship between criminal responsibility and the absence of mental illness."

I am not sure what you mean here.  As far as I can see,  adjudged criminal responsibility has little if any relationship to psychiatrically recognized mental illness.  Consider the great over-representation of the mentally ill in prisons.   A third of the US population approve of executing the mentally ill on Death Row.

Criminal responsibility is a binary concept. One is or is not criminally responsible. In the English and Australian common law tradition, responsibility is determined according to the McNaghton Rules, or legislative variation thereof. But other factors, such as less debilitating mental impairments and even poverty are relevant on sentencing if they lessen moral culpability. The hard line on responsibility promotes autonomy because it is assumed that all actors have moral agency. 

Our prisons too, are full of mentally impaired offenders.

In Canada, criminal responsibility is defined by the person's capacity to understand what they were doing was (morally or legally) wrong and to be in control of their actions. The legal defense is to refute criminal responsibility on account of mental disorder, resulting in the status of Not Criminally Responsible on account of Mental Disorder (NCRMD).

Note that it's not simply a question of whether someone has a mental disorder or not. The defense requires that the mental disorder affected the person's criminal responsibility. As a hypothetical example, having a diagnosis of schizophrenia and repeated hospitalizations as a result is not sufficient evidence; the defense requires that symptoms account for the criminal behavior, such as a delusion that the victim of an assault was trying to control one's mind, and thus the act was one of self-defense.

We recently published a series of open-access articles on our large-scale study of persons found NCRMD in Canada -- the National Trajectory Project -- in the March 2015 issue of the Canadian Journal of Psychiatry. You can find the link below. 

Thank you all for your answers!

Anthony, my claim is based on the thousands of years when mental illness has formed the basis for non-culpability. Of course the degree of mental illness has changed and today, at least in Sweden, it has to be a severe mental illness which in praxis means psychosis and the like. That is some of the öegal part of the question.

Your answer put forward that many are those in prison that are mentally ill and that a third of the American people approve of the Death penalty of mentally retarded offenders. This is to me ethically issues: (i) is it morally defensible that mentally ill are held crminally responsible and put in prison and (ii) the Death penalty in itself (!) and when it should be carried out.

As long as prisoners get good psychiatric care it may be OK. To me the Death penalty is morally wrong in itself and when used even on persons suffering from mental retardation I get nothing but angry.

Pontus

The high prevalence of mentally disordered offenders in jails and prisons in the US is related to the psychiatric deinstitutionalization movement. Mentally ill individuals who would get into trouble for relatively "minor" offenses like possession of drugs, theft, vandalism, etc are no longer sent to hospital but instead are criminally charged.

This seems to be a broader trend, not only the US. We discuss these trends in a 2011 review article that can be requested through ResearchGate.

Jansman-Hart, E. M., Seto, M. C., Crocker, A. G., Nicholls, T. L., & Côté, G. (2011). International trends in demand for forensic mental health services. International Journal of Forensic Mental Health, 10(4), 326-336.

Thank You Michael,

I will with great interest take part of your suggestions!

The trend to hold mentally ill to a larger extent is troublesome from at least three perspectives: the tendency to focus on holding more offenders criminally responsible instead of preventive work, the potential lack of treatment of the mentally ill when in prison and risk for additional stigma of the very same Group.

To me is the question of whom to hold criminally responsible subordinated the one of how to prevent an offender from committing a crime again. The damage is already done, so to speak.

Pontus

In some jurisdictions if a person suffers an epileptic fit and loses conscious awareness in the post ictal state. Criminal responsibility in that state is not acceptable. Criminal responsibility is also exempted in self defence situations.  Assuming the trial outcome establishes self defence.  The suicide pact is another way to elude criminal responsibility.

One factor that is relevant to the legal question of criminal responsibility is cognitive capacity. For example, individuals who are very cognitively impaired as a result of developmental disability or organic conditions could be found not criminally responsible (I don't think of cognitive impairment as falling under the rubric of mental disorder or illness.) 

Hi Pontus,

I think there are a number of socio-cultural factors that affect assessments of criminal responsibility when the focus shifts from the negation of the capacity for criminal responsibility to questions dealing with the degree of criminal responsibility or questions involving issues such as provocation (e.g. provocation interpretation biases resulting from background experiences that affect social information processing, see Fontaine's writings on the subject (2009) and my book on death penalty mitigation Ashford (2013).  Fontaine's work raises cognitive capacity  considerations consistent with  Michael Seto's point, but capacity concerns germane to social influences.

In addition, impaired socialization is a factor that can affect  a defendant's capacity for moral agency.   Peter Arenella's moral agency model  of criminal responsibility takes into account  capacity and choice considerations that do not limit questions of capacity to psychiatric factors.  

Factors in socialization that contribute to moral damage that are beyond a person's control are indeed relevant to other theories of criminal responsibility associated with choice and character approaches to criminal responsibility, but often have more to do with questions of moral culpability than legal culpability and this is why they have been relegated to the mitigation of punishment.  But, there are contexts in which they are very relevant to assessments of criminal responsibility when volitional tests are included in tests of criminal responsibility