This study investigates 30 lone actors in Sweden with a register-based design using a group of male lone actors and two reference groups: same-sex siblings and other male violent extremists. We compare lone actors to the reference groups along social background, criminal background, and co-offending relations (1995 –2016), and mental health (1980–2016). Our results show that lone actors are primarily born in Sweden to two Swedish-born parents. They have a high degree of criminality and co-offending, indicating that they are not completely loners in their criminal behaviour. They have higher enrolment in secondary education than the reference groups, but lower enrolment in higher education than other male violent extremists. Additionally, they suffer considerably more from mental disorders compared to the reference groups. An analysis of criminality and in- and outpatient hospitalisation over the life course indicates that lone actors may have had problems in their transition into middle age.

Aim: The current study explores heterogeneity in the aggregate age-crime curve. This is achieved by analyzing to what extent there is empirical support for the existence of pivotal typologies in developmental and life-course criminology, as well as whether there is any heterogeneity in trajectories among adult-onset offenders (first recorded for crime at age 25 or later).Methods: Data were drawn from a population-representative birth cohort of 14,608 males and females, followed prospectively in registers from age nine to 64. Trajectories of antisocial and criminal behavior were identified by means of group-based trajectory modelling.Results: A small group with a high prevalence of crime across the life course, among both males and females, was found. Furthermore, a large proportion of offenders were adult-onset offenders, and there was meaningful heterogeneity in their criminal trajectories. However, the data did not lend much support to the hypothesized phenomenon of late-blooming.Conclusion: There is meaningful heterogeneity in the aggregate age-crime curve, including trajectories that resonate fairly well with predictions derived from Moffitt's taxonomy. Nevertheless, there are firm reasons for theorizing proximate causes for the onset and continuation of crime beyond emerging adulthood.

Background: Intellectual disability (ID), schizophrenia spectrum disorder (SSD), bipolar disorder (BD), substance use disorder (SUD), and other mental disorders (OMDs) are associated with increased risks of criminality relative to sex-matched individuals without these conditions (NOIDMD). To resource psychiatric, addiction, and social services so as to provide effective treatments, further information is needed about the size of sub-groups convicted of crimes, recidivism, timing of offending, antecedents, and correlates. Stigma of persons with mental disorders could potentially be dramatically reduced if violence was prevented.Methods: A birth cohort of 14,605 persons was followed to age 64 using data from Swedish national health, criminal, and social registers.Results: Percentages of group members convicted of violence differed significantly: males NOIDMD, 7.3%, ID 29.2%, SSD 38.6%, BD 30.7%; SUD 44.0%, and OMD 19.3%; females NOIDMD 0.8%, ID 7.7%, SSD 11.2%, BD 2.4%, SD 17.0%, and OMD 2.1%. Violent recidivism was high. Most violent offenders in the diagnostic groups were also convicted of non-violent crimes. Prior to first diagnosis, convictions (violent or non-violent) had been acquired by over 90% of the male offenders and two-thirds of the female offenders. Physical victimization, adult comorbid SUD, childhood conduct problems, and adolescent substance misuse were each associated with increased risks of offending.Conclusion: Sub-groups of cohort members with ID or mental disorders were convicted of violent and non-violent crimes to age 64 suggesting the need for treatment of primary disorders and for antisocial/aggressive behavior. Many patients engaging in violence could be identified at first contact with clinical services.

Objectives: The current study analyzed the association between a final paternal conviction that occurred sometime 10 years prior to birth through age 14 and subsequent child conviction risk to age 25.Methods: We used Swedish register-based data on a two-generation dataset originating from a parental generation born in 1953. We employed a combination of population-averaged models that controlled for measured confounding together with an analysis of full siblings that ruled out unmeasured confounding shared between full siblings.Results: The results showed that boys, but not girls, who were exposed to a paternal conviction during upbringing had an increased risk of being convicted themselves, net of measured and unmeasured familial confounds. There was, however, little indication for an age-effect at the time of a final paternal conviction, and there were no significant differences in violent crime between exposure-discordant siblings.Conclusions: The results provide evidence for an effect of the exposure to a paternal conviction on child subsequent conviction risk that cannot merely be explained by familial factors shared between full siblings. These results are, however, conditional on gender and on the type of criminal outcome.