The diagnosis of CD first appeared in the third edition of the DSM and has undergone two revisions ( ₉ ). The first set of changes occurred in the revised third edition of the DSM ( ₁₀ ) when several nonviolent anti-social behaviors were removed from the diagnostic criteria ( ₁₁ ). The second set of modifications came in the fourth edition of the DSM ( ₁₂ ) which included the addition of new criteria: bullying, staying out late at night despite parental prohibitions, a modification of the lying criteria, and a change in the time periods in which the symptoms must be evident.

The current CD diagnosis is defined as a “repetitive and persistent pattern of behavior in which the basic rights of others and major age-appropriate societal norms or rules are violated” (p. 98) ( ₁₃ ). The DSM-IV-TR currently lists four categories for the diagnosis of conduct disorder in children and adolescents: (1) aggression, (2) destruction of property, (3) lying or theft, (4) and serious violation of rules. Grouped under each of these four categories, the DSM outlines 15 specific behaviors used to diagnose CD. For example, the specific criteria listed under the aggression category include: “(1) often bullies, threatens, or intimidates others, (2) often initiates physical fights, (3) has used a weapon that can cause serious physical harm to others, (4) has been physically cruel to people, (5) has been physically cruel to animals, (6) has stolen while confronting a victim, (7) has forced someone into sexual activity.” (p. 98-99) ( ₁₃ ) CD has also been differentiated into two subtypes: adolescent onset (age 11 and after) and childhood onset (before the age of 11). Finally, to receive a diagnosis of CD, an individual needs to manifest three of the 15 specific behaviors in the past 12 months and at least one behavior in the past six months ( ₁₃ ).

The prevalence rates of CD vary widely. Currently, the DSM-IV-TR reports that prevalence rates range “from less than 1% of the population to more that 10%” (p. 97) ( ₁₃ ). Other researchers have reported CD to be one of the most common reasons for referral ( ₁₄ ), with some estimates putting the percentage of children with conduct disorder between the three to five percent range and these numbers can double in adolescence ( ₁₅ ). In a comprehensive review of seven studies of over 10,000 children (5,212 males and 5,226 females, age 5-15) diagnosed with ODD and CD, it was indicated that CD is far more common in males (2.1%) than females (0.8%). This study also reported a steady increase in the rate of CD diagnosed males, while the level of diagnosis of CD among females remained low until around age 12 ( ₁₆ ). This coincides with Moffitt and Capsi’s ( ₁₇ ) male to female ratio of 10 to 1 for children diagnosed with CD, but only 1.5 to 1 (males to females) for adolescents diagnosed with CD.

Researchers have also discovered a later onset (with a mean onset age of 13) and less linear stability in the development of anti-social behavior among females ( ₃ ) as opposed to males who appear to develop anti-social behavior in a more linear fashion, around age seven ( ₈₁₈ ). However, there is some evidence of early onset, stability, and different types of anti-social behavior among females. Côte, Zoccolillo, Tremblay, Nagin, and Vitaro ( ₁₉ ) undertook a 10 year longitudinal study of disruptive behavior among females. Results indicated that females with a medium or high level of disruptive behavior between kindergarten and the sixth grade are over 4 times more likely to receive the diagnosis of CD than females in the non-disruptive groups. Another study found males and females to exhibit equal levels of conduct problems, especially when covert behavioral problems are considered conduct problems ( ₂₀ ). Furthermore, this research brings to question if developmental issues need to be considered when assessing the prevalence of CD, as well as whether the gender difference in prevalence rates of CD in childhood and adolescence are actually different or a reflection of bias within the DSM criteria.

The DSM criterion for CD is expected to be gender neutral; however, there are considerable differences in prevalence rates between males and females. One explanation for this may be that a gender bias exists within the CD diagnosis ( ₆ ). Widiger and Sptizer ( ₂₁ ) define bias as “a systematic deviation from an expected value” and a sex bias as “a systematic deviation that is associated with the sex of the subject” (p.3). McLaughlin ( ₂₂ ) outlined three specific ways bias can influence a DSM diagnosis. The first is sampling bias (dealing with how the sample is chosen), the second is assessment bias (how clinical information is gathered), and finally criterion bias (when the criteria is more valid for one group than another is) ( ₂₂ ). It is essential to explore how the literature addresses each of these types of biases when considering the possibility of gender bias in the CD diagnosis.

In examining assessment bias, it is important to consider who is reporting the problematic behavior. When assessing problematic behavior in children and adolescents, the referral generally comes from someone other than the patient. This is an important consideration as teachers and parents may more often focus on overt behavior which they find particularly troubling ( ₇ ) and the referral sources may be completely unaware of hidden problems.

Sampling bias may also be a contributing factor to the possibility that gender bias may exist in the CD diagnosis. Zoccollilo ( ₆ ) outlines three areas in which this may become problematic. One way a sampling bias could have emerged comes from the belief that the CD diagnosis is so rare among females that research has had a tendency to over-emphasize the study of males or combine males and females into one population. Second, many of the subjects used in the research on CD come from the criminal justice system. This is problematic due to higher rates of arrest and imprisonment of males, which has unintentionally led many researchers to study only males diagnosed with CD. Third, females may be more likely to be found outside the settings of psychiatric system and may therefore be underrepresented in a clinical population ( ₆ ).

With regard to criterion bias, Zoccollilo ( ₆ ) points out that most of the studies used to validate the criteria for the diagnosis of CD were composed primarily of males, which he argues may have led to bias in the symptomology of the CD diagnosis. Based on this and other research, Zoccolillo ( ₆ ) argues that the CD criteria or threshold for the diagnosis needs to be adjusted to more accurately reflect the behaviors of females.

One additional area worth noting is in the section on “Specific Cultural, Age, and Gender Features” for diagnosing CD in the DSM-IV-TR. In this section, it is suggested that males diagnosed with CD “frequently exhibit fighting, stealing, vandalism, and school discipline problems,” while females “exhibit lying, truancy, running away, substance abuse, and prostitution” (p. 97) ( ₁₃ ). Using these behaviors as a guide, it would be more consistent for these behaviors, for both males and females, to be used as symptoms for the diagnosis. Winstead & Sanchez ( ₂₃ ) noted that two specific behaviors outlined for females, substance abuse and prostitution, are not listed in the DSM as criteria for CD; whereas, all of the described behaviors for males are listed as criteria. Furthermore, this section lends some credence to Zoccollilo’s ( ₆ ) premise that there are differing ways in which CD can be manifested and that gender has an influence on the symptoms of CD

Bias may have also been accentuated when the undersocialized, non-aggressive subtype found in the DSM-III was replaced by more severe forms of aggressive behavior found in the DSM-III-R and DSM-IV. Some researchers believe that the more severe forms of aggression found in the later versions of the DSM are more indicative of how CD presents itself in males ( ₁₄₂₄ ), while the more non-aggressive behaviors were associated with CD in females ( ₂₅ ).

In a more recent study of the gender sensitivity of the disruptive behavioral disorders, Ohan & Johnston ( ₅ ) undertook two specific investigations to see how mothers would rate the gender appropriateness of the criteria for all three disruptive behavior disorders. Results support the idea that the current symptoms for CD are more indicative of a male pattern of anti-social behavior. Ohan & Johnston ( ₅ ) also added an additional set of more “female sensitive items for CD” (p. 369). These items were centered on emotional blackmail and cruelty, social cruelty, leaving school with members of the opposite sex, and stealing non trivial items. These “female-sensitive” items were rated by mothers to be more indicative of a female behavior, but were not considered as problematic as the current criteria for CD. In their second study, Ohan and Johnston ( ₅ ) attempted to link the “female sensitive items for CD” to the current diagnosis of CD. Results of this study were inconclusive for CD, but for both ADHD and ODD the researchers were able to find a link between the “female sensitive” items and the current ADHD and ODD constructs. Overall, these studies add an important piece to the puzzle on whether the current criterion for CD has a specific gender bias. It seems from these results that there may be a male bias in the current criterion for CD and that the inclusion of the more “female-sensitive” items may be able to alleviate some of the bias. Unfortunately, the researchers were not able to assess the degree of relatedness between the “female sensitive” CD items and the current DSM-IV symptoms for CD ( ₅ ).

From this review, it appears there are number of ways in which bias, specifically gender bias, has impacted the CD diagnosis. From the sampling and criterion bias outlined by Zoccolillo ( ₆ ), to the possible criterion bias pointed out by Winstead & Sanchez ( ₂₃ ), there seems to be a pattern of using symptomology that is less indicative of disruptive behavior in females. While this research does not indicate that significant changes are needed in the DSM, it does point to the idea that mental health professionals need to have a firm grasp on the different ways disruptive behavior can manifest, especially among females. The next section of this review will outline some the current research on other ways that disruptive behaviors and specifically aggression can manifest.

Aggression has generally been defined as “intent to harm” ( ₂₆₂₇ ) and has been found to be one of the best predictors of future antisocial behavior ( ₂₈₂₉₃₀ ). Unfortunately, there have been some limitations in the study of aggression with much of the past research on aggression focusing on the more overt forms of aggression, such as physical and verbal aggression ( ₂₆₃₁₃₂ ). Not unexpectedly, some researchers, including Ohan & Johnston ( ₅ ), have suggested “the terms ‘physical violence’ and ‘aggression’ are often considered synonymous” (p.360). Additionally, this singular focus on physical aggression has inadvertently led to the study of aggression in males, who engage in physical aggression far more often than their female counterparts ( ₃₃₃₄ ). While it is true that females do engage in physical aggression, a much larger group of females have been shown to engage in less physical and more socially manipulative forms of aggression ( ₃₅ ). Fortunately, researchers have begun to reverse the trend of primarily studying more overt aggression and have begun studying the subtypes of aggression where the aggressor may be less obvious and uses the social milieu to attack ( ₂₉₃₆ ). Furthermore, much of this research has found females to use these less obvious forms of aggression more often than males in both childhood and adolescence, but upon entering adulthood, these gender differences have been shown to diminish.

Research on these less obvious forms of aggression began in the early 1970’s, but it was not until Lagerspetz, Björkqvist, & Peltonen’s ( ₃₇ ) article that an extensive research agenda was undertaken. Currently three differing forms of non-physical aggression have been identified in the literature. The first, indirect aggression, was defined “as a kind of social manipulation: the aggressor manipulates others in order to attack the victims, or, by other means, makes use of the social structure in order to harm the target person, without being personally involved in the attack” (p. 52) ( ₃₈ ). The second, relational aggression, was first used in the Crick and Grotpeter ( ₃₉ ) study of aggression in 8 to 12 year olds. Relational aggression was defined as “harming others through purposeful manipulation and damage of peer relationship” (p. 711) ( ₃₉ ). Finally, a third subtype of aggression is social aggression. Social aggression was first identified in the Cairns, et al. ( ₃₅ ) study of children in grades four to seven and more extensively investigated in Galen and Underwood’s ( ₄₀ ) article on aggression. In that article, social aggression was defined as “behavior which is directed toward damaging another’s self-esteem, social status, or both, and may take such direct forms as verbal rejection, negative facial expressions or body movements, or more indirect forms such as slanderous rumors or social exclusion” (p. 589) ( ₄₀ ).

From these definitions, it becomes clear that relational, social, and indirect aggression all use the social milieu to harm another person; however, there are some subtle differences. For example, social aggression encompasses the use of negative body language and facial expressions (mean looks and gestures), whereas relational aggression does not ( ₄₁ ). Furthermore, indirect aggression is entirely covert (as the intended target is completely unaware of the attacker), while relational aggression will employ some face to face attacks, such as threats to end the friendship if one does not do as they are asked. While these differences may seem insignificant, they have generated controversy in the literature and have led to the multiple avenues of research ( ₄₂ ). However, despite the controversy, there is enough overlap between the constructs that many researchers believe that indirect, relational, and social aggression are generally describing the same construct ( ₂₆₄₁ ).

A number of developmental theories have been proposed to explain the development of indirect, relational, and social aggression. When Crick and Grotpeter ( ₃₉ ) first investigated relational aggression they began with the premise that males and females would use the type of aggression that most damages the important social goals of their respective genders. For males, dominance is the key social goal ( ₄₃ ), therefore using physical aggression can cause significant damage to social dominance. For females, intimacy is the prominent social goal in their relationships ( ₄₃ ); consequently, relational aggression is used to undermine this intimacy. Björkqvist, Lagerspetz, & Kaukiainen ( ₃₈ ) proposed that indirect aggression developed on a different track than physical aggression, as it requires the development of verbal skills and social intelligence. In addition, these researchers asserted that indirect aggression is a more sophisticated method of attack, as the victim is unaware of the attacker ( ₃₈ ). This premise could have significant implications on whether the attacker’s behavior will come to the attention of parents and teachers and be used to formulate an accurate assessment of the individual.

As stated earlier, the current CD diagnosis is defined as a “repetitive and persistent pattern of behavior in which the basic rights of others and major age-appropriate societal norms or rules are violated” (p. 98) ( ₁₃ ). For relational aggression to be considered within the context of this definition, it is important for the research to show that relational aggression is a “persistent pattern of behavior” and “violates the social norms and right of others.” With regard to the “persistent pattern of behavior” section of the definition, research has found evidence of relational, indirect, and social aggression in preschool ( ₄₄₄₅ ), at all grade levels in elementary school and high school ( ₃₇₃₈₃₉ ), in college students ( ₄₆ ), and well into the life span ( ₄₇ ). Additionally, a number of studies have found a steady increase in the use of relational aggression as females enter adolescence ( ₄₈ ). Unfortunately, this review found only one study that examined the same individuals over a one year span. Their findings indicate that among preschool students (N=19), relational aggression is a stable behavioral pattern one year from the original measurement ( ₅₀ ).

The question then becomes whether relational aggression is problematic enough to be considered disruptive behavior and “violates the social norms and right of others.” Similar to the study of frequency and gender differences, research has demonstrated significant links between engaging in and/or being the victim of indirect, relational, or social aggression and social/psychological issues and developmental problems ( _3239495152 ). For example, among preschool students the use of relational aggression was found to predict peer rejection 18 months later ( ₅₃ ). Also, in a study of 4 [[[th]]] and 5 [[[th]]] grade students, victimization by relational aggression was linked to lower levels of peer acceptance, increased levels of peer rejection, submissive behavior, social avoidance, loneliness, emotional distress, lower levels of self-restraint, and social anxiety ( ₄₉ ). In a study among adults, victimization by indirect aggression was correlated with higher levels of depression, anxiety, and aggressiveness ( ₅₄ ). Other research has found significant links between the use of the relational aggression and psychosocial problems. In the Prinstein, Boergers, and Vernburg study ( ₅₅ ), the use of relational aggression was linked to an increase in depressive symptoms, loneliness, and lower scores on a self-worth inventory. These researchers also found that individuals who were victims of both overt and relational aggression were the most susceptible to adjustment difficulties ( ₅₅ ).

In addition, relational aggression has also been shown to be associated with other violent acts. In a study of violence of middle school and high school students, backbiting (unkind remarks) was found to be an important precursor to violence. Backbiting by the antagonist was followed by an accusation of wrongdoing by the respondent. The accusation then led to a denial of wrongdoing by the antagonist. From these initial interactions, numerous verbal attempts were used to influence the outcome and finally violence was used to resolve the conflict ( ₅₆ ). Although relational aggression was not specifically mentioned in this article, backbiting appears to fit with the overall theme of relational aggression ( ₅₆₅₇ ). Furthermore, there is a possible connection between bullying and relational aggression. Bullying has been defined as “a student is being bullied or victimized when he or she is exposed, repeatedly and over time, to negative actions on the part of one or more other students” (p. 9) ( ₅₈ ). Some specific actions of bullying include indirect methods, such as spreading rumors and intentionally excluding someone from a group ( ₅₈ ).