Escalation in the severity of conduct problems and delinquency: The clinical relevance of developmental pathways
It is not new that some parents fear that one or more of their children at some point in their life would escalate from a fierce temper to committing violence. Judge the following quote referring to the early life (in about 1749) of a later famous scientist and author:
‘You’, said my mother to me [when I was five to six years old], ‘have naturally a violent temper: if you grow up to be a man without learning to govern it, it be impossible for you then to command yourself; and there no knowing what crime you may in a fit of passion commit, and how miserable you may in consequence of it become. You are but a very young child, yet I think you can understand me. Instead of speaking to you as I do at this moment, I might punish you severely; but I think it better to treat you like a reasonable creature. My wish is to teach to command your temper; nobody can do that for you, so well as you can do it for yourself.’
This recollection was written by Richard Lovell Edgeworth (1744-1817) of Edgeworthstown, Co. Longford, Ireland, an enlightened landowner, brilliant educator, and inventor. The quote comes from the American edition of Edgeworth’s memoirs (Memoirs of Richard Lovell Edgeworth, Esq. begun by himself and concluded by his daughter Maria Edgeworth. Boston: Wells and Lilly, 1821, pp. 11-12) and then related how he managed to subsequently restrain his temper and lead a very prosocial and productive life.
The quote illustrates how different juvenile behaviors such a volatile temper may precede and develop in the commission violence. Scientists have had different points of view on to best study such development from childhood into adulthood. Some scientists have focused on the fact that individuals differ in the extent and severity of their problem behaviors (usually referred to as the individual differences approach) and that these individual differences are relatively speaking static and stable over time (e.g., Gottfredson and Hirschi, 1990).
Several other scientists have posed that it is important to study developmental sequences between different problem behaviors (e.g., Kandel, 2002). A developmental sequence is defined as the orderly behavioral development of two mutually exclusive behaviors that occurs at a rate that is better than chance. Yet a third group of scientists have emphasized the need to study certain categories of individuals from a developmental point of view. The common threat here is that individuals differ in their development trajectories of antisocial behavior over time. Thus, the emphasis is on the identification of different developments by different categories of individuals and this may lead to loss of information about individual differences relevant in clinical settings. Often these studies refer to the documentation of different development trajectories of problem behaviors in that some show a high stable trajectory, others a decreasing trajectory, while a third group of individuals show a low stable trajectory of an antisocial behavior (for a review see e.g., Piquero, 2008).
Stable individual differences, developmental sequences and trajectories can produce a lot of specific information about juveniles’ development of antisocial behavior, but such information is not always sufficiently useable in clinical work with juveniles showing antisocial and/or delinquent behavior. First, the three concepts tend not to focus on within individual change with development, which is most relevant to clinicians. Second, trajectory studies rarely address the fact that often the development of one problem behavior may be followed by the development of several other problem behaviors, leading to diversification of antisocial problem, and increased severity of antisocial problem behaviors over time. This often is referred to as heterotypic development in that differ types of behaviors unfold with development from childhood into adulthood, and that each of these different behaviors tend to have a certain stability over time. Studying diversification and escalation is important because such study can help us to understand better how different categories of problem behaviors ‘fit together’ in a cumulative model over several years of development into the initiation of serious antisocial behaviors such as violence, including homicide, and serious property offenses.
One of the main points in this paper is to show that young people who commit acts of violence or serious theft rarely do so de novo. Instead, many criminologists, child psychologists and psychiatrists agree that the majority of youth who commit acts of violence or serious theft have practiced less serious forms of conduct problems or delinquency earlier in life (e.g., Elliott, 1994; Elliott & Menard, 1996; Loeber et al., 1992; Loeber et al., 1993; Le Blanc, 2002; Rutter, Giller & Hagel, 1998; Warr, 2002).
In risk factor research on juvenile delinquency and juvenile problem behaviors it is commonly accepted to use a cumulative risk factor model as a foundation for what was named equifinality and multifinality decades ago (e.g., Cichetti & Rogosch, 1996). Equifinality means that young people with different risk factors and circumstances become delinquent compared to multifinality where seemingly the same risk factors lead to different outcomes. Since this is a well-known concept for researchers as well as for clinicians, it is import to relate this to developmental pathways in this paper, although we are not reviewing risk factors. Many clinicians work from the notion of equifinality and multifinality, and we will argue that this complex interaction pattern leading to a certain outcome is best studied through developmental pathways (in contrast to developmental sequences or trajectories).
The key question is what type of model(s) best fit the fact that not all juveniles displaying minor problem escalate to the most serious behaviors (e.g., Loeber & Le Blanc, 1990; White, Jackson & Loeber, 2009). Traditionally, researchers have investigated the orderly (rather than random) development between different forms of problem behaviors such as oppositional behavior, conduct problems, delinquency, and adult crime (collectively called externalizing problems) trying to find the models that best explain the fact that not all juveniles with certain problem behaviors escalate to the most serious behaviors (e.g., Le Blanc & Loeber, 1998; Loeber & Le Blanc, 1990). For example, the onset of violence is usually preceded by a history of escalation in the severity of aggression, which often, but not always, starts in childhood (Loeber, 1988; Loeber et al., 1993; Moffitt, 1993), but many youth with the earlier problem behavior do not escalate to violence. This is the reason why this paper focuses on developmental pathways to serious antisocial outcomes. We define developmental pathways as the sequence of unfolding of a variety antisocial behaviors over time leading to the manifestation of serious antisocial acts. Ideally, developmental pathways allow us to map individuals’ escalation from minor to very serious antisocial acts, while taking into account that individuals differ in their escalation processes and the extent that they display only minor antisocial problems, escalate to moderately serious acts, or escalate to serious antisocial outcomes.
Why is knowledge of developmental pathways important for clinicians?
As discussed, there is an ongoing debate among scientists on the merits of the study of developmental sequences, developmental trajectories and developmental pathways, and what and when it is appropriate to focus on. What is less clear for clinicians is what the differences are and why these differences are relevant for clinicians’ in their day to day work with patients and clients. We argue that information conveyed by developmental pathways, in contrast to developmental sequences and trajectories, often is closer to the complex reality which clinicians face about the presentation and evolution of the antisocial problems presented by their clients/patients. It is very rare that a patient have a clean cut problem, that developed as a consequence of a single previous event or characteristic (as in a developmental sequence), or following a developmental pattern based on average findings of a group of people (as in developmental trajectories). It is likely that the reason for a patient’s help seeking or referral to a mental health specialist is only one component in a complex daily life. For the clinician this poses challenges in terms of weaving together the different parts of information, and here, knowledge about developmental pathways can help determine what types of behaviors are commonly interconnected and in what temporal order. What distinguishes pathways from other developmental methods (developmental sequences and trajectories) is the clear focus on individuals and their differences to escalate from minor to more serious problem behaviors. Pathways can therefore be seen (as compared to sequences and trajectories) as a developmental window based on dynamic rather than static processes.
With the above discussion in mind we will address in this paper the following clinically relevant questions:
- What is a comprehensive and clinically relevant escalation model from minor problem behaviors to serious property crime, violence and homicide, and do research findings support best support a single or multiple pathways?
- What are the limitations and benefits of developmental pathways in clinical work?
Several researchers have proposed that the development towards delinquency can be explained by one single pathway (e.g., Elliott, 1994; Gottfredson & Hirschi, 1987; Osgood et al., 1988). Other researchers have questioned this and have hypothesized that there several different pathways leading to serious antisocial outcomes.
The question of whether there are single or multiple pathways to serious outcomes is important, since research on delinquency careers show that, by adulthood, offending outcomes of active offenders are far from uniform. For example, when using trajectory analyses a distinct category of violent chronic offenders emerges, who often engage in a variety of other types of offenses (Loeber & Farrington, 1998). Another example of a distinct category of specialized offenders are property offenders with an onset in adolescence, who have little or no history of violent offenses. Finally a third group of offenders consists of repeat property offenders (without violence) but a much later onset in adulthood (Loeber & Farrington, 2012). Thus, some youth mostly engage in property crime, others in violence, and a third group in both. In addition, some youth develop conduct problems but do not become property offenders, violent offenders or both, but a proportion of those with early conduct problems develop into delinquent offenders. In other words, individuals’ life course of conduct problems and delinquency varies on several basic parameters – oppositional behavior, conduct problems and delinquency - and these individuals differ in terms of the severity of the conduct problems and delinquency they display during development. This is one reason why Loeber and colleagues (Loeber et al., 1993) proposed that there is no single pathway to individuals’ escalation to a serious antisocial outcome, that instead, there are several pathways.
Representations of developmental pathways tend to fall under the rubric of escalation models because less serious problem behaviors tend to precede more serious behaviors (Loeber & Le Blanc, 1990). Thus, developmental pathways chart how individuals escalate from innocuous to very serious problem behaviors. Because violence and more serious crime tend to occur and become more visible in late adolescence and early adulthood, we are interested in the identification of individuals who display early risk of for serious behavioral problems, years before they actually take place. In this line of work, developmental pathways are useful in helping clinicians and researchers understand which temporal sequences of several problem behaviors increase the risk of later escalation into serious criminality. By doing so, this knowledge can be incorporated in early interventions to be discussed later.
Using longitudinal data to model developmental pathways.
In this paper we jump right into a description of the steps undertaken by Loeber and his team of researchers to identify pathway towards serious antisocial outcomes. First, Loeber and Schmaling (1985) investigated the extent to which different problem behaviors were correlated with other problem behaviors. For that purpose, the authors performed a multidimensional scaling of problem behaviors based on 28 cross-sectional factor analytic studies covering over 11,000 children. The purpose of doing this was primarily to establish the extent to which certain behavior problems loaded on a single factor (meaning that they were highly correlated) while other problem behaviors loaded more on another factor. This procedure established the extent to which a single pathway model would be sufficient or whether the data would better fit a multiple pathway model. The authors found one single externalizing dimension but with two different poles, one of overt, confrontational behaviors, and the other consisting of covert, concealing behaviors. Disobedience, a feature often referred to as an important developmental milestone, was situated at an equal distance between overt and covert acts on this dimension. Frick et al. (1993) repeated the factor analysis based on a larger sample of factor analytic studies, and confirmed the presence of the overt-covert dimension of externalizing behaviors, but they also documented a destructive vs. nondestructive dimension. Since that time, the distinction between overt and covert externalizing behaviors has been accepted by many researchers (e.g., Vassallo et al., 2002).
Figure 1: Three developmental pathways in externalizing behaviors
(Loeber et al.)
On the basis of research findings described above, Loeber and colleagues (Loeber et al., 1993) formulated a parsimonious model of three pathways (Figure 1). The first pathway is called the Overt Pathway and concerns externalizing and confrontational acts. This pathway starts with minor aggression often early in childhood (e.g., bullying, annoying others), has physical fighting (physical fighting and gang fighting) as a second step, and serious violence (rape, attack, robbery) as a third step. This escalation is also related to age development factors, for example an older child is more able to commit more serious externalizing acts due to physical maturity.
The second pathway is called the Covert Pathway and concerns concealing acts. This pathway starts prior to age 15 with minor covert acts (shoplifting and frequent lying), has property damage (e.g., vandalism and fire-setting) as a second step, has moderate delinquency (e.g., fraud, pick-pocketing) as a third step, and has serious delinquency (e.g., auto theft and burglary) as a fourth step. Also here, it is important to realize that cognitive maturity plays a role in the escalation of concealing acts.
The third pathway is called the Authority Conflict Pathway. This pathway takes place prior to the age of 12, and usually starts with stubborn behavior, and has defiance/disobedience as a second step, and authority avoidance (e.g., truancy, running away from home, and staying out late at night) as a third step.
Based on analyses using longitudinal data from the Pittsburgh Youth Study (PYS), Loeber et al. (1993) showed that the development of externalizing problems in boys took place systematically rather than randomly, and best fitted the three different pathways rather than a single pathway (Loeber, Keenan & Zhang, 1997; Loeber et al., 2005).
The observed pathways are hierarchical in that those who have advanced to the most serious behavior in a given pathway usually have displayed persistent problem behavior characteristics of an earlier stage. By a process of selection, increasingly smaller groups of youth become at risk for the more serious behaviors. The three-pathway model has been subsequently replicated across two other samples in the Pittsburgh Youth Study (Loeber, Wung et al., 1993; Loeber, DeLamatre et al., 1998). The pathways model has been replicated in four other longitudinal data sets (Loeber et al., 1998; 1999; Tolan et al., 2000), and has been featured in publications of the Office of Juvenile Justice and Delinquency Prevention (Kelley et al., 1997) and the Centers for Disease Control (Dahlberg & Potter, 2001).
Are the three pathways mutually exclusive?
Loeber et al.’s (1993) pathway model accommodated the fact that some youth are primarily engaging in covert acts but are not very aggressive, but that some aggressive youth also engage in theft offenses. Thus, the three-pathway model does not represent mutually exclusive pathways; instead, youth can be on a single pathways, two pathways, or in the worst case, on three pathways. The authors found that escalation in either the Overt or Covert Pathway was often preceded by escalation in the authority conflict pathway (Loeber et al., 1993). In other words, early conflict with authority figures, especially parents, often constitute a stepping stone in juveniles’ progression in the Overt and/or Covert Pathway. Also, an early age of onset of problem behavior or delinquency, compared to an onset at a later age, was more closely associated with escalation to more serious behaviors in both the Overt and Covert Pathways (Tolan, Gorman-Smith & Loeber, 2000). In addition to this, as boys who escalated to higher steps in the pathway model, tended to also continue with the earlier, less serious forms of problem behaviors (called retention of problem behaviors). Moreover, as youth escalated to serious problem behavior, the frequency of their offending tended to increase.
The pathways model was tested and evaluated in several ways. First, the backward probabilities were computed, to establish the extent to which individuals who had reached a later step in a pathway had also gone through the preceding steps. The results showed that most of those who reached a higher step in a pathway also had manifested problem behaviors characteristic of a lower step in the pathway. This applied to each of the three pathways. Second, the pathways model accounted for the majority of self-reported high-rate offenders and court-reported delinquents.
Experimenters and Persisters.
Developmental pathways to serious forms of delinquency should be studied in the context of normal development, including the fact that many youth show some externalizing problems at some time in their early life, as a part of testing boundaries and exploring their own social skills (recall the experimenters). Several of the early steps in the pathways take into account that some degree of problem behaviors are normal. To distinguish normal from abnormal development, Loeber et al. (1997) distinguished between experimenters and persisters, with experimenters displaying low frequency and low persistence of behaviors, while persisters show a pattern of persistent problem behaviors. One example is disobedience, which is at a low frequency relates to experimenters, but with a disobedience the young person might develop into a persister. Loeber et al. (1997) found that more persisters, compared to experimenters, entered a pathway at the initial and lowest step. Also, fewer persisters, compared to experimenters, initially entered a pathway at a second or later step. Thus, the identification of pathways was better when experimenters were omitted from the data, and was improved by concentrating on persisters. From a societal and clinical point of view it is much relevant to focus on persisters in treatment.
Serious violence and homicide as an extension of the violence pathway.
In the early stages of the development of the pathways model, very few of the boys in the PYS, because of their young age, had committed homicide. Although we speculated that early violence would be a stepping stone toward homicide, this hypothesis could only be tested in recent years when the homicide rate among the young males in the PYS had increased. Longitudinal analyses (Ahonen, Loeber & Pardini, 2015; Loeber et al., 2005; Loeber & Farrington, 2013) showed that 94% of the homicide offenders had been violent (e.g., engaged in aggravated assault, robbery or rape) earlier in their life (as evident from self-reports and official records of violence). Thus entering the first stage on the Overt Pathway. We therefore propose that serious violence and homicide offending among these inner-city young males is an additional, fourth step in the Overt Pathway, with other forms of preceding violence being a necessary condition for later serious violence and homicide offending.
Do the Pathway Model apply Equally Well to Girls?
Traditionally, and today, previous research reports more extensively on males rather than females. Girls have a much lower base rate of delinquent behaviors than boys, both according to self-reports and official charges (e.g., Loeber et al., 2015), which makes female delinquency more difficult to study. One crucial question is whether girls show similar pathways in externalizing behaviors as boys do, when taking the lower base rate into account? Using longitudinal data from the first five waves of the National Youth Survey (which is a US nationally representative sample), Gorman-Smith and Loeber (2005) found similar developmental patterns of externalizing and delinquent involvement among girls. There is a clear need to replicate these findings.
Some limitations and benefits of developmental pathways in clinical work
There are several limitations to the pathway models, which can be addressed in future research. One is that only a restricted number of behaviors are included in several of the pathway models. In the PYS, the reason is that the initial approach to identifying steps in the pathways depended on charting onset curves for different behaviors based on longitudinal data (Loeber et al., 1993). Those behaviors that showed similar onset curves were placed on the same step in a pathway. The onsets of several externalizing behaviors were less consistent and, for that reason they were excluded from the formulation of the pathways model. Another set of delinquent acts (gang membership, gun carrying and drug dealing) had a relatively low base rate, most likely because the participant’s young age, when the developmental model was first investigated (Loeber et al., 1993) and for that reason were not included at that time.
The analyses of pathways in the PYS were inherently limited by the fact that the youngest boys in the study were age 6 at the beginning of the assessments. Although retrospective information from the parent was collected, this source of information often is incomplete and, therefore, prospective information from infancy needs to form the basis for future formulations of developmental pathways in externalizing behavior during the preschool period. Such work needs to take advantage of information about temperament as a precursor to externalizing behaviors (e.g., Frick & Morris, 2004; Keenan & Shaw, 2003).
Much more needs to be known about de-escalation models of change, showing the order in which individuals shed problem behaviors as they improve or desist (Loeber & Le Blanc, 1990). Pathways in externalizing problems should be seen in the context of incomplete development of social skills and competencies incompatible with externalizing problems. In addition, it is likely that developmental pathways overlap with poor impulse control, poor moral development and cognitions favorable to rule and law breaking.
Developmental pathways are much relevant in clinical everyday treatment settings for assessment, prevention, and the evaluation of interventions. Schools, juvenile justice agencies and medical and mental health providers all struggle to find the most efficient ways to provide primary, secondary and tertiary modes of intervention. Assessments of juvenile externalizing behaviors are justified when results are relevant for an appraisal of current behaviors and future risk, and knowledge of developmental pathways can be incorporated with the prediction of the future risk of escalation by specifying at least two important parameters: (a) which behaviors are linked to later progression to serious outcomes and in which combination; and (b) which populations of youth are at risk of progressing to more serious acts. Assessment instruments based on knowledge of developmental pathways can also aid in the identification of those youth whose problem behavior is temporary or intermittent (so called experimenters) compared with those whose problem behavior is likely to persist and escalate in severity (Loeber et al., 1997; Loeber, Slot & Stouthamer-Loeber, 2006).
Developmental pathways are also important for specifying targets in preventive interventions. For instance, if the presence of antisocial behavior or conduct problems (as distinguished from more general and less serious externalizing behavior) is a key predictor of the later emergence of delinquency, this would have dramatic implications for the search for reliable early indicators of high risk for later severe externalizing behavior. If severe antisocial and delinquent behavior in late childhood or adolescence was predicted not by oppositionality or defiance but by more specific early antisocial or conduct problems, or by specific types of temperament or dimensions of dysregulation, it would be much easier to identify those children who are likely to develop antisocial behavior problems and avoid making false positive predictions. This can only be done with knowledge about developmental pathways and within-individual change, as compared to trajectory analyses (categories of behaviors and individuals) or sequential analyses where only one behavior is studied at one time. Accordingly, well-targeted and specifically tailored prevention strategies could be delivered.
Developmental pathways can also help to increase the ways by which intervention success is evaluated. Typically, the success of a given intervention is evaluated in more of an all-or-nothing and immediate fashion. We argue that, instead, the change in individual propensity to escalate along a developmental pathway is a more refined and, possibly, a more developmentally informed intervention outcome. Finally, we argue that knowledge based on developmental pathways is more relevant for clinicians than knowledge based on simple developmental sequences or trajectory analyses, and can be more easily translated into therapeutic assessments and actions.
This paper highlights an escalation model documenting steps by which some youth escalate from minor antisocial problems to serious forms of delinquency, including violence. To highlight the features of such an escalation model, we contrast it with knowledge of developmental sequences and developmental trajectories, preferring a more clinically relevant escalation model of different pathways to serious antisocial outcomes. The escalation model presented consists of three pathways, one referring to escalation from minor aggression to violence (called the overt pathway), the second pathway referring to escalation from minor to major property offenses (called the covert pathway), while a third pathway represents escalation in conflict with authority figures. The pathway escalation model has been intensely researched and validated on longitudinal data for boys and girls. Implications for clinical practice are highlighted.
This work is supported by grants from the Commonwealth of Pennsylvania (SAP 4100043365) to Drs. Loeber and Burke, the National Institute of Mental Health (MH 074148) to Dr. Burke, and (MH056630 and MH056630) to Dr. Loeber, while The Swedish Research Council supported Dr. L. Ahonen’s work. The paper summarizes the key points of two chapters (Loeber & Farrington, 2003; White, Loeber & Farrington, 2008) and two papers (Loeber, White & Burke, 2012) and Loeber (2013).
Prof. Dr. R. Loeber (Ph.d), Distinguished Professor of Psychiatry, Professor of Psychology and Epidemiology University of Pittsburg, USA. Email: firstname.lastname@example.org
Mw. Lia Ahonen (Ph.D, M), Universitetslektor, School of Law, Psychology and Social Work, Örebro Universitet, Örebro, Sweden.
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