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Mats Christoffer CarlssonDirector of graduate studies

About me

I received my PhD in 2014 and have been a senior lecturer in criminology since 2018. In the meantime, I worked as a researcher at the Institute for Futures Studies, in a study on organized crime, violent extremism, and criminal networks. Since 2022, I have been an associate professor in criminology.

Teaching

Together with Emeli Lönnqvist, I am course coordinator for Introduction to Criminology at the undergraduate level, on campus, and also responsible for the same e-learning course. I also teach at the advanced level, primarily the course Controversies in Criminology. Since the autumn semester of 2025, I am been Director of Studies for advanced level studies.

Research

My research has broadly focused on the role of crime in individuals' lives over time: why do people start committing crimes? Why do they stop? What do these processes look like? I have mainly explored these questions using qualitative methods, but I have also participated in several research projects that involve both the use of quantitative data and statistical methods of analysis.

Research projects

Juvenile crime in Sweden

Juvenile delinquency is one of the central problem areas both in criminological research and in Swedish public debate. Several of Sweden experts on juvenile delinquency are involved in this book project, which has been ongoing since 2001.

Cover photo: Den svenska ungdomsbrottsligheten

Publications

A selection from Stockholm University publication database

  • Lone threats: a register-based study of Swedish lone actors

    2024. Amir Rostami (et al.). International Journal of Comparative and Applied Criminal Justice 48 (1), 75-94

    Article

    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.

    Read more about Lone threats

  • Offending trajectories from childhood to retirement age: Findings from the Stockholm birth cohort study

    2024. Fredrik Sivertsson (et al.). Journal of criminal justice 91

    Article

    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.

    Read more about Offending trajectories from childhood to retirement age

  • The burden for clinical services of persons with an intellectual disability or mental disorder convicted of criminal offences: A birth cohort study of 14,605 persons followed to age 64

    2024. Sheilagh Hodgins (et al.). Nordic Journal of Psychiatry 78 (5), 411-420

    Article

    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.

    Read more about The burden for clinical services of persons with an intellectual disability or mental disorder convicted of criminal offences

  • Is There a Long-Term Criminogenic Effect of the Exposure to a Paternal Conviction During Upbringing? An Analysis of Full Siblings Using Swedish Register Data

    2023. Fredrik Sivertsson, Christoffer Carlsson, Andreas Hoherz. Journal of quantitative criminology 39 (1), 53-73

    Article

    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.

    Read more about Is There a Long-Term Criminogenic Effect of the Exposure to a Paternal Conviction During Upbringing? An Analysis of Full Siblings Using Swedish Register Data

  • Age, Gender, and Crime in a Stockholm Birth Cohort to Age 64

    2021. Christoffer Carlsson, Fredrik Sivertsson. Journal of developmental and life course criminology 7 (3), 359-384

    Article

    We study the criminal histories of 14,608 males and females in a full Stockholm birth cohort born in 1953 to age 64. Using an update of The Stockholm Birth Cohort Study data, we explore the amount of crimes recorded in the cohort before and after the advent of adulthood. We break down the age/crime curve into separate parameters, including onset, duration, and termination. Throughout, we utilize the large number of females (49%; n = 7 161) in the cohort, and compare long-term patterns of male and female criminal careers. Next, we focus on adulthood, and explore the existence and parameters of the adult-onset offender and its contribution to the overall volume of crime in the cohort. While crime peaks in adolescence, the main bulk of crimes in the cohort occurred after the dawning of adulthood. Nearly half of all male, and more than two-thirds of all female, crimes in the cohort occurred after age 25. In the case of violence, the majority of offences - around two-thirds for both genders - took place in adulthood. Around 23% of all males and 38% of all females with a criminal record in the cohort were first recorded for a criminal offence in adulthood. While a majority were convicted only once, a proportion of adult-onset offenders had a considerable risk of recidivism and repeated recidivism. These results suggest that quite a substantial proportion of the population initiate crime in adulthood, and that these offenders account for a nonnegligible proportion of adult crime.

    Read more about Age, Gender, and Crime in a Stockholm Birth Cohort to Age 64

  • A Life-Course Analysis of Engagement in Violent Extremist Groups

    2020. Christoffer Carlsson (et al.). British Journal of Criminology 60 (1), 74-92

    Article

    In this exploratory study, individuals’ processes of engagement in violent extremist groups are analysed by drawing from criminological life-course theory and narrative-based understandings of crime. Based on interviews with individuals who have participated in violent extremism, it is suggested that the process of engagement consists of three steps: (1) a weakening of informal social controls, followed by (2) an interaction with individuals in proximity to the group and (3) a stage of meaning-making in relation to the group and one’s identity, resulting in an individual’s willingness and capacity to engaging in the group’s activities, including violence. In future theorizing about processes of engagement in violent extremism, the meanings of age, and the life-course stages of late adolescence and emerging adulthood in particular, should be given analytic attention.

    Read more about A Life-Course Analysis of Engagement in Violent Extremist Groups

  • Continuity, Change, and Contradictions: Risk and Agency in Criminal Careers to Age 59

    2015. Fredrik Sivertsson, Christoffer Carlsson. Criminal justice and behavior 42 (4), 382-411

    Article

    This study's point of departure is the current debate over the ability to make prospective long-term predictions of criminal offending based on childhood risk factors. We begin by constructing groups based on cumulative childhood risk and measure their subsequent criminal career outcomes. The results show clear differences in adult offending but also considerable heterogeneity, suggesting that the relationship between risk factors and individuals' subsequent offending or non-offending is complex and in need of closer study. We therefore identify individuals in the low-and high-risk groups who did not develop the criminal careers that could be expected from their risk scores and, using deviant case analysis, qualitatively analyze their life histories. Together, these cases inform us of the importance of the dynamics of risk, human agency, and the life course, as well as the historical influences under which their lives unfolded-features of social life that could in no way be predicted prospectively.

    Read more about Continuity, Change, and Contradictions

  • Continuities and Changes in Criminal Careers

    2014. Christoffer Carlsson.

    Thesis (Doc)

    The best predictor of future criminal behavior is past criminal behavior. At the same time, the vast majority of people who engage in crime are teenagers and stop offending with age. Explaining these empirical findings has been the main task of life-course criminology, and contributing to an understanding of how and why offenders continue their criminal careers once they have started, and how and why they stop, is also the purpose of this dissertation.

    To do this, the dissertation studies a number of facets of the criminal career: the importance of childhood risk factors (Paper I), the notions of turning points (Paper II) and intermittency (Paper III), and the connection between masculinities and criminal careers (Paper IV). In contrast to much life-course criminological research, the dissertation mainly relies on qualitative life history interviews, collected as part of The Stockholm Life Course Project.

    The findings suggest a need for increased sensitivity to offenders’ lives, and their complexity. Whereas continuity and change can be understood within a frame of age-graded social control, this perspective needs to be extended and developed further, in mainly three ways. First, the concept and phenomenon of human agency needs closer study. Second, lived experiences of various forms of social stratification (e.g. gender, ethnicity, and so on) must be integrated into understandings of continuity and change in crime, seeing as phenomena such as social control may be contingent on these in important ways. Third, this dissertation highlights the need to go beyond the transition to adulthood and explore the later stages of criminal careers.

    In closing, the dissertation suggests that we move toward a focus on the contingencies of criminal careers and the factors, events, and processes that help shape them. If we understand those contingencies in more detail, possible implications for policy and practice also emerge.

    Read more about Continuities and Changes in Criminal Careers

  • Masculinities, Persistence, and Desistance

    2013. Christoffer Carlsson. Criminology (Beverly Hills) 51 (3), 661-693

    Article

    In life-course criminology, when gender has been the focus of study, it has predominantly been treated as a variable. Studies that explore the gendered nature of criminal careers through the lived experiences of offenders are rare, even though these studies can make important contributions to our understanding of crime and the life course. Analyzing qualitative data, this article uses life-history narratives of a small sample of male juvenile delinquents (N = 25), born in 1969–1974, to explore the possible link among masculinities, persistence, and desistance from crime. The findings of the study suggest that processes of persistence and desistance are imbued with age-specific norms of what it means to “be a man” and successfully do masculinity in different stages of life. Analyzing these gender-specific practices gives a deepened understanding of processes that underlie the offenders’ lives as they go through stages of continuity and change in crime. The findings of the study further suggest a complex intersection between gendered biographies and gendered structures, with fruitful contributions to life-course criminology. The implications of these findings are discussed.

    Read more about Masculinities, Persistence, and Desistance

  • Processes of Intermittency in Criminal Careers: Notes From a Swedish Study on Life Courses and Crime

    2013. Christoffer Carlsson. International journal of offender therapy and comparative criminology 57 (8), 913-938

    Article

    This article explores the concept of “intermittency” and uses qualitative lifehistory narratives with male offenders from The Stockholm Life Course Projectto distinguish between two qualitatively different forms of intermittent offending.Findings suggest that one form of intermittency can be characterized by “breaks”and “pauses” in offending, where the offender for a period of time “holds up” butwithout attempting to commit to any long-term change in trajectory. The secondform can best be understood as incomplete or aborted attempts at desistance, whereattempts to change are present but not realized. Perceived or experienced failure toenter conventional roles and engage in conventional practices is highly relevant tounderstand these attempts. The intermittent zigzag patterns of offending observed inquantitative studies of criminal careers can thus actually entail qualitatively differentlife course processes of continuity and change. Implications for policy and futureresearch are highlighted.

    Read more about Processes of Intermittency in Criminal Careers

  • Using 'Turning Points' to Understand Processes of Change In Offending: Notes from a Swedish Study on Life Courses and Crime

    2012. Christoffer Carlsson. British Journal of Criminology 52 (1), 1-16

    Article

    Processes of within-individual change in offending and desistance from crime can be very complex, often involving multiple, context-specific processes. But even in a generous reading of much research on turning points, while this is theoretically stated or inferred, it is less often shown or illustrated in empirical cases. I explore processes of change in offending with the help of the concept of ‘turning points’, through life story interviews conducted in the Stockholm Project, trying to make use of the possibilities inherent in qualitative inquiry. I show how life course processes and the turning points that emerge within them are often interdependent on each other, emerging in very context-specific circumstances, and need to be studied and understood and such. Future research areas are suggested.

    Read more about Using 'Turning Points' to Understand Processes of Change In Offending

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