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About forensic psychiatric research

Our focus is on forensic psychiatry in the broadest sense: identifying and assessing psychiatric, psychological and neurobiological factors that impair the ability of people to adapt their behaviour to comply with the laws in force and thereby refrain from committing crimes. It can be said that forensic psychiatry complements sociological criminology, which analogously studies social factors that have a similar effect on people. Forensic psychiatry now works almost exclusively with violent crime and personal crime (defined as antisocial aggression), not with property crime, economic crime, drug-related crime or other types of crime. Our main research question can be formulated as follows: Why do some people demonstrate more aggressive antisocial behaviour than others? The basic scientific assumption in forensic psychiatry is that people who demonstrate such behaviour have an impaired ability to adapt their behaviour to the expectations that govern interaction with other people or society at large, and that this impairment is reflected in their behaviour. The extent to which such actions are instead the result of free will, that someone chooses to behave badly, renders the explanatory models of forensic psychiatry meaningless.

The behavioural difference among people with respect to aggressive antisocial behaviour is our dependent variable; in other words, it is the factor we are attempting to explain, where more incidents of expressed antisocial aggression and more serious consequences form a quantitative measure. The temporal aspects are important; behavioural patterns can be perceived either in a here-and-now perspective or in a life perspective. An important hypothesis in research in this field is that aggressive antisocial behaviour with onset during childhood is a more serious problem than late-onset aggression of this type. Past behaviour is always the strongest indicator of future behaviour. A clinical term for this type of behaviour disorder is antisocial personality disorder, as defined by the onset of aggressive antisocial behaviour, known as conduct disorder, before age 15. People with this problem comprise one to two percent of the population and account for over half of all violent crimes, especially those that are serious or directed against a partner. In recent years, we have come to understand that these individuals comprise a large portion of all adult psychiatry patients, often having other diagnoses that complicate the prior behaviour disorder, ranging from schizophrenia and various psychoses to mood disorders, anxiety and substance abuse/dependence.

After thus defining the dependent variable, the next step is to define those factors that may explain the differences among people in antisocial aggressive behaviours (known as explanatory factors, or synonymously as independent variables, background factors, risk factors or vulnerability factors). Our research group works with various explanatory factors obtained from clinical assessments of behaviour and experiences, psychological tests of mental abilities, descriptions of social circumstances, neurobiological variables derived from testing of blood and cerebrospinal fluid, brain imaging techniques and molecular genetics.

Because this is an empirical science, we assume that both the dependent variable and the various explanatory factors are subject to quantitative assessment. Our work must begin with methodological considerations to determine what human aspects we are quantifying, what they can tell us, what they cannot tell us, and what sources of error may affect quantification. Knowledge is rooted in epistemological frameworks in which the scientific method imposes limits on the interpretations of the obtained results. We study aspects of reality. If we are aware of the limitations of a quantitative approach to human behaviour, what remains is essentially mathematics. Correlations between interpersonal variability in antisocial aggression and the various explanatory factors can be calculated (using group comparisons or correlative measurements), as can their explanatory value, which is to say, the portion of variation in antisocial aggression that is statistically attributable to a particular explanatory factor or to a certain combination of such factors. In an ideal scientific model, psychiatric and psychological factors should obviously be considered side by side with social and biological factors, where the respective importance of the various factors is empirically determined.

Once statistical correlations have been established, the next step is to determine whether the explanatory factors are also causal factors for the behaviour (INUS conditions: Insufficient, Non-redundant parts of Unnecessary but Sufficient Causes). A causal factor underlying a behaviour does not have to be a sufficient or a necessary cause, but it must be non-redundant and together with other factors sufficient to cause the behaviour. On the group level, when we refer to antisocial aggression in society, we must ascertain whether a statistical explanatory factor is also an INUS condition based on theoretical considerations of circumstances, such as whether the factor generally precedes the behaviour in time, whether there is a credible mechanistic explanation for the correlation, and whether it is believed that the behaviour would not occur in the absence of the factor. For example, alcohol intoxication can be considered to be an INUS condition underlying violent crime; in itself it is insufficient to cause the behaviour (frequent intoxication does not lead to crime), it is not a necessary condition for the behaviour (many cases of such violence are not preceded by intoxication), but there is a statistical correlation between antisocial aggression and intoxication: intoxication often precedes violence, there is an understandable link between impaired judgment and heightened aggression during intoxication, and finally there are many examples of violence during intoxication that would be difficult to envision without intoxication. Based on similar considerations, we do not assume that tattoos are a causal factor underlying antisocial aggression, regardless of any statistical correlation between prevalence of tattoos and use of violence. Quite simply, there is no credible mechanistic explanation for why tattoos would cause antisocial aggression. If a researcher should someday find a dye in tattoos that causes increased aggression in animal experiments, we would need to reconsider our conclusion. Conclusions about causal relationships based on statistical correlations will therefore always need to be reconsidered based on new findings. It is important to keep in mind that all treatment of risk factors for antisocial aggression or preventive measures to counter antisocial aggression are based on assumptions about causal relationships, because it would be pointless to treat a statistical explanatory factor that is not really a causal factor.

To this point, the forensic psychiatric model is theoretically simple – or at least, it should be so. Rather, the difficulty lies in applying scientific knowledge to an individual case in relation to a particular crime (often referred to as clinical application). Forensic psychiatric, psychological and criminological models identify causes of human behaviour, thereby capturing those human aspects that are causal (that is, in some sense conform to law). We are unable to address what behaviour may be based on anything other than causes, such as free will, choices, such as good and evil, or chance. Explanatory factors in forensic psychiatry will therefore limit our freedom of action, including our ability to achieve insight (where ‘normal’, in the statistical sense, cognitive abilities are a prerequisite for adapting behaviour to norms and laws).

We can summarize the circumstances governing our work as follows: If forensic psychiatry and other scientific disciplines succeed in identifying factors that together constitute sufficient cause for a particular action (in our case an act of antisocial aggression) or in explaining 100% of the variation in this behaviour, we can conclude that there is no reason to believe that the person in question had the capacity to freely choose the action. But in most cases, our explanatory factors can explain parts of the variation or reflect contributory but insufficient causes. In such situations, we can only explain what we are able to and describe the general meaning of the various explanatory factors that were at issue, based on what we know about antisocial aggression at the group level. Such circumstances or factors can then ‘subtract’ from the conceivable freedom a person may have to choose in a particular situation, but cannot tell us anything about that freedom, which must instead be assessed by those who might wish to consider the moral significance of an action, such as lawyers. The task of forensic psychiatry is to explain the extent to which we have been able to identify such limitations to the capacity of an individual to act freely, and society should of course demand that we account for our knowledge and conclusions as precisely as possible.

Contact Information

Henrik Anckarsäter

Centre for Ethics, Law and Mental Helth, Wallinsgatan 6, 431 41 Mölndal, Sweden

Visiting Address:
Wallinsgatan 8, Mölndal

Page Manager: Stefan Axelsson|Last update: 6/23/2014

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