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Chapter 3:
The Developmental Dynamics of Youth Violence

Early- and Late-Onset Trajectories

Onset and Prevalence of Serious Violence

Cumulative Prevalence

Rates of Offending and Violent Careers

Developmental Pathway to Violence

Chronic Violent Offenders

Superpredators?

Co-Occurring Problem Behaviors

Offending and Victimization

Transition to Adulthood

Conclusions

References

Chapter 3


RATES OF OFFENDING AND VIOLENT CAREERS

Violent youths commit a remarkably high number of crimes (Tolan & Gorman-Smith, 1998). An analysis of NYS data shows that these young people (both male and female) averaged 15.6 rapes, robberies, aggravated assaults, or some combination of these crimes over a 16-year period (1976 to 1992) (Elliott, 2000b). What's more, they averaged just over six serious violent offenses each during the years in which they were active (Elliott, 2000b).10 This mean annual rate of offending is similar to rates reported in the three city surveys for males (about 5 to 9 serious violent offenses per year) (Huizinga et al., 1995) but much higher than the rates for females (2 to 4.5 per year).

It is noteworthy that the mean annual rate of individual offending appears to be essentially unchanged over the past two decades. This finding is corroborated by a study of trends among juvenile offenders processed by a county court system in Arizona (Snyder, 1998) and by an analysis of both National Crime Victimization Survey data and arrest records (Snyder & Sickmund, 2000). Finally, the Monitoring the Future survey (see Chapter 2) found no significant changes in individual offending rates for robbery or assault with injury between 1983 and 1993.11

Career length has been variously defined as the number of years of active offending, the maximum number of consecutive years, or the span between the first and last year during which a young person meets the criteria for a serious violent offender (Blumstein et al., 1986). There are relatively few estimates of violent career lengths. In the NYS, the mean career length (number of years of active violent offending) was 2.6 years. The most frequent career length was 1 year (36.8 percent of serious violent offenders). Three-quarters of these serious violent youths had careers lasting 3 years or less, and 15 percent had careers of 5 years or more (Elliott, 2000b). Based on 5 years of data, the Denver survey reports that 42 percent of serious violent youths were active for only 1 year, 22 percent for 2 years, and 31 percent for 3 or more years (Huizinga et al., 1995).

The typical violent career comprises either a single year of continuous offending or a longer period of intermittent offending. Relatively few violent careers are characterized by years of uninterrupted violence. In Denver, well over half of the careers that lasted three or more years had at least one year with no violent offending; three-quarters of those that spanned a 5-year period had an intermittent pattern of offending (Thornberry et al., 1995). Evidence that most careers lasting more than 1 year were characterized by intermittent offending also surfaced in the NYS (Elliott et al., 1986). This intermittent pattern makes it difficult to identify serious violent offenders with cross-sectional studies or with longitudinal studies that have long periods between data collection (Huizinga et al., 1995).

In sum, these studies suggest that in most cases violent careers are relatively short and are characterized by intermittent offending. During active periods, however, most careers are marked by a high rate of violent offending—up to 10 offenses per year (Elliott et al., 1986; Thornberry et al., 1995).

DEVELOPMENTAL PATHWAY TO VIOLENCE

Violent youths do not usually begin their careers with a serious violent offense. While the developmental pathway varies, depending on what types of behavior are monitored, studies generally agree that a violent career begins with relatively minor forms of antisocial or delinquent behavior. These acts later increase in frequency, seriousness, and variety, often progressing to serious violent behavior (Elliott, 1994; Loeber et al., 1998; Moffitt, 1993; Tolan & Gorman-Smith, 1998). Several complex pathways to serious violence have been proposed (Loeber, 1996; Elliott, 1994).

The NYS suggests that violence escalates over time. Most serious violent youths who engage in multiple types of violent behavior begin with aggravated assault, then add a robbery, and finally a rape. (Rape appears to be the endpoint of the progression, although there were not enough homicides in the NYS sample to include homicide in the analysis.) Robbery precedes rape in over 70 percent of cases in which both acts have been reported, and about 15 percent of serious violent offenders in the NYS reported having committed a rape (Elliott, 1994, 2000a). This sequence must be considered tentative because it is based on a single study.

When serious violence becomes part of a youth's repertoire of antisocial behavior, it does not substitute for less serious forms of violence; rather, it adds to them and escalates the overall frequency of violent acts. Thus, serious violent youths are high-frequency offenders who are involved in many less serious as well as serious offenses. These youths account for a major share of all criminal behavior, a pattern that is explored more fully in the next section.

CHRONIC VIOLENT OFFENDERS

A minority of serious violent youths are responsible for the overwhelming majority of serious violent crime, a finding supported by numerous self-report and arrest studies (Tolan & Gorman-Smith, 1998; Tracy & Kempf-Leonard, 1996). In the city surveys, chronic offenders, though representing less than 20 percent of all serious violent offenders, accounted for 75 to 80 percent of self-reported violent crimes (Huizinga et al., 1995). NYS data yield similar findings: Chronic offenders (youths with three or more violent offenses) accounted for 76 percent of all felony assaults and 89 percent of all robberies reported by offenders in 1980 (Elliott et al., 1989).

Chronic violent youths may also account for a disproportionate share of all youth crime. The NYS reveals that in 1980 these serious violent offenders accounted for 79 percent of all felony theft, 66 percent of all illegal services (primarily drug selling), and 50 percent of all self-reported crime (Elliott et al., 1989). In the Philadelphia Birth Cohort Study, 15 percent of youthful offenders accounted for 74 percent of all official crime (Tracy & Kempf-Leonard, 1996).

As noted earlier, youths whose violence begins before puberty are more likely to become chronic violent offenders (Loeber et al., 1998). In the Rochester survey, 39 percent of children who initiated violent behavior by age 9 eventually became chronic offenders, 30 percent of those who initiated violence between the ages of 10 and 12 became chronic offenders, and 23 percent of those who initiated violence after age 13 became chronic violent offenders. In Denver, 62 percent of those initiating violence by age 9 and 48 percent of those initiating violence between 10 and 12 became chronic violent offenders. Looking at this another way, 55 percent of all chronic violent offenders in Denver came from the early-onset trajectory (Thornberry et al., 1995). While the late-onset trajectory involves a substantially larger group of youths, fewer than half of all chronic offenders come from this group.

Although most chronic violent offenders in the three city surveys (62 to 77 percent) eventually had contact with the police for some offense (though not necessarily a violent offense), one-quarter to one-third were never arrested (Huizinga et al., 1995). Among those who were arrested for some offense, the first contact came well after they had begun their violent careers. Interventions by the justice system occur too late to prevent such youths from escalating from less serious offenses to serious violence. Fortunately, it appears that at least half of chronic violent offenders can be identified as being at risk in childhood.

Research has found a powerful relationship between membership in a gang and chronic involvement in serious violence (see review in Thornberry, 1998). As noted earlier (see Chapter 2), gang members, a relatively small proportion of the adolescent population, commit the majority of serious youth violence (see Spergel, 1990, and Thornberry, 1998, for reviews).

SUPERPREDATORS?

Between 1983 and 1993, adolescents were committing homicide at dramatically higher rates than in previous years (see Chapter 2). Did those youths represent a new breed of frequent, vicious, remorseless killers? Did the character of violent youths change during that time—and is it still different today (Bennett et al., 1996)? The answer seems to be no, for several reasons.

First, the increase in homicides was similar across all age groups (see Chapter 2). This suggests that it resulted from a relatively sudden change in the environment that affected all youths rather than from a gradual change in the socialization process, which would have led to progressively more vicious youths with each succeeding age group. Second, the increase in homicides was highly specific to certain youths—namely, African American males (Zimring, 1998); moreover, it did not take place among females (see Chapter 2). Third, during the violence epidemic, there was a decline in family members killed by youths (Cook & Laub, 1998).

Fourth, a new breed of superpredators should have resulted in more burglaries, auto thefts, and larcenies, but no such increases occurred (Cook & Laub, 1998). It should also have resulted in more homicides involving knives and other weapons, but this did not occur (Zimring, 1998). Fifth, there was no evidence that individual rates of serious violent crime changed during the epidemic. More youths were involved, but the average number of offenses committed by each did not change. Finally, there may be anecdotal evidence that today's youths show less remorse for their violence, but this has not been substantiated by research.

In sum, the epidemic of violence from 1983 to 1993 does not seem to have resulted from a basic change in the offending rates and viciousness of young offenders. Rather, it resulted primarily from a relatively sudden change in the social environment—the introduction of guns into violent exchanges among youths. The violence epidemic was, in essence, the result of a change in the presence and type of weapon used, which increased the lethality of violent incidents (Wintemute, 2000).

CO-OCCURRING PROBLEM BEHAVIORS

Serious violence is accompanied by a wide range of other problem behaviors, including property crimes, substance use, gun ownership, dropping out of school, early sexual activity, and reckless driving. The co-occurrence of these problem behaviors has been borne out by numerous national and local studies (see reviews in Elliott, 1993; Huizinga & Jakob-Chen, 1998; Tolan & Gorman-Smith, 1998).

The overlap is greatest between serious violence and other forms of crime. In the three city surveys, 82 to 92 percent of chronic violent youths were involved in property crimes, 71 to 82 percent in public disorder crimes, and 26 to 45 percent in selling drugs (Huizinga et al., 1995). Very similar rates were found in the NYS (Elliott et al., 1989). Rates of co-occurrence were much higher among serious violent youths than among less violent youths.

Substance use and abuse are a central feature of a violent lifestyle (Dembo et al., 1991; Elliott, 1994; Elliott et al., 1989; Esbensen & Huizinga, 1991; Fagan, 1993; Johnson et al., 1991). In the Denver survey, for example, about 58 percent of serious violent offenders were alcohol users and 34 percent were marijuana users. The prevalence and frequency of use were much lower in youths who were not seriously violent (Huizinga & Jakob-Chen, 1998). The NYS indicates that 94 percent of serious violent youths in 1980 were using alcohol, 85 percent were using marijuana, and 55 percent were using several illicit drugs. Over half (55 percent) were abusing drugs—that is, they reported health or relationship problems, or both, associated with their drug use (Elliott et al., 1989).

Similar findings regarding the overlap of substance use and serious violence hold for the Rochester study (Thornberry et al., 1995). Moreover, chronic violent youths in Rochester and violent youths in the NYS had higher rates of dropping out of school, gun ownership and use, teenage sexual activity and parenthood, tobacco use, driving under the influence of alcohol or drugs, and gang membership than nonserious offenders or nonoffenders (Elliott, 1993; Thornberry et al., 1995).

In sum, these studies show that a sizable proportion of serious violent youths have co-occurring problem behaviors—and at rates significantly higher than those of their less violent counterparts. However, by no means all serious violent youths or even all chronic violent youths have co-occurring problems. Moreover, not all youths with problem behaviors are seriously violent. The fact that serious violence and problem behaviors tend to occur together does not necessarily mean that one causes the other (see Chapter 4) (Elliott, 1993; Reiss & Roth, 1993).

Violence and Mental Health
The relationship between violence and mental health has been studied more intensively in adults than in young people. An earlier U.S. Surgeon General's report on mental health, after weighing the evidence, emphasized that the contribution of mental disorders to overall violence in the United States is very small. In fact, public fear is out of proportion to the actual risk of violence, which contributes to the stigmatizing of people with severe mental disorders (Link et al., 1999). Even though the risk of violence is low overall, it is greatest for adults with serious mental disorders who also abuse substances (Steadman et al., 1998; Swanson, 1994).

Although violence is relatively widespread among adolescents, few studies have been undertaken on the co-occurrence of violence and mental health problems or disorders among U.S. adolescents. Such population-based studies are important because they avoid the bias inherent in surveying hospitalized patients or convicted offenders.

Both the NYS and the Denver survey examine the co-occurrence of serious violence and mental health problems. In the NYS, 28 percent of serious offenders age 11 to 17 were classified as having mental health problems, compared to 13 to 14 percent of nonserious delinquent youths and 9 percent of nonoffenders. Youths were classified as having mental health problems on the basis of their responses to questions about emotional problems, social isolation, and feelings of loneliness (Elliott et al., 1989). (The questions were not designed to arrive at a diagnosis of a mental disorder.) Serious violent offenders were more likely than either nonserious offenders or nonoffenders to report having these types of mental health problems.

In the Denver study, serious violent youths were found to have higher rates of psychological problems, based on parents' responses to the Child Behavior Checklist (Achenbach & Edelbrock, 1983). These problems included externalizing and internalizing behavior, depression, uncommunicativeness, obsessive-compulsive behavior, hyperactivity, social withdrawal, and aggressiveness. The rates at which most of these problems occurred in serious offenders were no different from the rates at which they occurred in nonviolent delinquent youths; however, rates in nondelinquent youths were lower. Thus, delinquent youths in general were more likely to have psychological problems than nondelinquent youths (Huizinga & Jakob-Chen, 1998).

Two problems were linked directly to violent behavior—externalizing symptoms and aggressive behavior. Approximately half of all serious violent offenders display these problems, although the link with externalizing behaviors is statistically significant only for boys. In addition, parents of violent offenders report seeking help for mental health problems more often than parents of nondelinquent or nonviolent delinquent youths. These parents did not go to mental health professionals or school counselors; rather, they sought the advice of friends, relatives, and spiritual leaders (ministers, rabbis, or priests). A similar finding is reported in the Pittsburgh study (Stouthamer-Loeber & Thomas, 1992).

The Denver study found no differences between the self-esteem of serious violent offenders and nonviolent offenders or nonoffenders (Huizinga & Jakob-Chen, 1998). In general, there is little evidence that low self-esteem causes violence or that violent offenders have low self-esteem. On the contrary, the evidence is more consistent with the position that high self-esteem and threats to high esteem lead to violence (Baumeister et al., 1996). This has important implications for treatment and intervention programs and the use of esteem-building activities in these programs.

A population-based study in New Zealand found that in young adulthood (age 21), serious violent offenders are more likely than nonoffenders to exhibit substance dependence disorders, schizophrenia-spectrum disorders,12 or both (Arseneault et al., 2000). These New Zealand findings are consistent with the studies of U.S. adults showing that the greatest risk of violence stems from the combination of serious mental disorder and substance dependence. However, about 10 percent of serious violent offenders13 in the New Zealand study exhibited schizophrenia-spectrum disorders without substance dependence or other psychiatric conditions. The researchers concluded that while the contribution of serious mental illness to violence in young adults remains small, it may be slightly higher than it is in adults. One possible reason for the difference is that the overwhelming majority of young adults with mental disorders in the New Zealand study had not been treated or hospitalized within the previous year.

Another recent community-based study found a link between personality disorders (a group of severe mental disorders) and violence. Adolescents with personality disorders,14 as determined by diagnostic interviews, were more likely than other adolescents to commit violent acts such as assault with injury and robbery (Johnson et al., 2000). For example, about 36 percent of adolescents with personality disorders versus 16 percent without the disorders committed a violent act against others15 during adolescence. The relationship between personality disorders and violence remained after taking many factors into account, including co-occurring depression, anxiety, and substance disorders. Only a few adolescents (13 percent) with personality disorders had received mental health services during the previous year (Johnston, personal communication, 2000).

Thus, there is some evidence of a relationship between serious mental disorders and violence in adolescents or young adults in the general population. Young people with serious mental disorders may be at risk of becoming violent if they also abuse substances or if they have not received treatment for their mental disorder. More research is needed to understand the relationship between serious youth violence and mental illness.

OFFENDING AND VICTIMIZATION

Violent offenders are frequently victims of violence (Esbensen & Huizinga, 1991; Lauritsen et al., 1991; Sampson & Lauritsen, 1990, 1994). Data from the NYS reveal that victimization is highest among African Americans, males, and frequent offenders (Lauritsen et al., 1991). In addition, youths who report abusing drugs and alcohol, hanging out with delinquent peers, and participating in social activities with little adult supervision are at greater risk of being victims of violence (Gottfredson, 1984; Lauritsen et al., 1991; Sampson & Lauritsen, 1990). A delinquent lifestyle greatly increases the likelihood of being a victim and appears to account for some of the disparities observed in offending and victimization by race/ethnicity and sex. The Denver survey shows that 42 percent of serious violent offenders are also victims of violence (Huizinga & Jakob-Chen, 1998), with higher rates among male offenders than female offenders.

There are many reasons for the overlap between offending and victimization. Perhaps the most common is that the offender is injured by the intended target—either during the offense or later, in retaliation. Another reason is that offenders tend to live in more violent environments or their lifestyles take them into high-risk environments. The predictive relationship between victimization and offending, as well as the relationship with early child abuse, is discussed in Chapter 4.


Footnotes
 
10  Active involvement is defined as any year during which offenders committed one or more serious violent offenses.
 
11  Calculations were done by the senior scientific editor Elliott on the basis of Monitoring the Future prevalence and frequency data on aggravated assault and robbery contained in the 1991 and 1998 Sourcebooks of Criminal Justice Statistics (Flanagan & Maguire, 1992; Maguire & Pastore, 1999). Individual offending rates are based on estimated incident rates. For this calculation, frequencies associated with categorical scores were as follows: not at all = 0; once = 1; twice = 2; 3 or 4 times = 3.5; and 5 or more times = 5. Individual offending rates for robbery in both 1983 and 1993 were 1.8. Rates for assault with injury were 2.3 and 2.6 (not significant). The mean individual offending rate can remain relatively constant despite increases in prevalence and incident rates noted in Chapter 2.
 
12  This broad category includes individuals who responded "yes, definitely" when asked if they had positive symptoms of schizophrenia (hallucinations and delusions) and for whom other plausible explanations (such as major depressive episodes or the influence of alcohol or illicit drugs) could be ruled out. The classification of diagnoses was made with the Diagnostic Interview Schedule.
 
13  Defined by two or more types of violent offenses (simple assault, aggravated assault, robbery, rape, and gang fighting) or a conviction.
 
14  The personality disorders included in this study were the same disorders (e.g., schizotypal disorder) studied by Arseneault et al. (2000).
 
15  Included threats to injure others, initiation of physical fights, mugging, robberies, or assaults resulting in injury during the past 1 to 4 years or during the individual's lifetime. The acts were reported in 1985-1986 or 1991-1993.
 


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