An item response theory analysis of DSM-IV conduct disorder

Abstract

Objective: We examined DSM-IV conduct disorder (CD) symptom criteria in a community sample of male and female adolescents to evaluate the extent to which DSM-IV criteria characterize the range of severity of adolescent antisocial behavior within and across sex.

Method: Interviews were conducted with 3,208 adolescents between the ages of 11 and 18 years using the Diagnostic Interview Schedule for Children. Item response theory analyses were performed to obtain severity and discrimination parameters for each of the lifetime DSM-IV CD symptom criteria. In addition, item response theory-based differential item functioning analyses were conducted to examine the extent to which the symptom criteria function similarly across sex.

Results: The DSM-IV CD symptom criteria are useful and meaningful indicators of severe adolescent antisocial behavior. A single item ("Steal without Confrontation") was a poor indicator of severe antisocial behavior. The CD symptom criteria function similarly across sex; however, three items had significantly different severity parameters.

Conclusions: The DSM-IV CD criteria are informative as categorical and continuous measures of severe adolescent antisocial behavior; however, some CD criteria display sex bias.

Figure 1

Item Characteristic Curves for Conduct Disorder items Figure 1 shows the item characteristic curves (ICCs) for each of the CD symptoms. On the x-axis, the severity of CD is scaled to have a mean of 0 and a standard deviation of 1 in males. The severity parameter for an item can be determined by identifying the point on the x-axis where the probability of endorsement (y-axis) is 50% (indicated by a dashed line). For example, the severity parameter for “Steal no Confrontation” is 0.24. The ICCs also depict the discrimination parameters of items; ICCs with steeper slopes have higher discrimination parameters.

Figure 2

Differential Item Functioning (DIF) results: Severity parameters (β) Figure 2 shows the results of tests of Differential Item Functioning (DIF) for each individual CD symptom. Each item is listed across the bottom of the figure. Squares indicate the severity parameters for each item for females, severity parameters for males are indicated by diamonds. Error bars provide the standard errors for these estimates. Items with significant DIF are identified by asterisks in the lower portion of the figure. DIF suggests that items do not indicate the same level of severity in males and females.

Figure 3

Test information curve for DSM-IV Conduct Disorder Figure 3 shows the test information curve (TIC) which displays how all Conduct Disorder criteria function together to provide information across the range of severity of the latent antisocial trait. X-axis = the latent antisocial trait expressed as z-scores. Solid line; left axis = total information aggregated across all Conduct Disorder criteria for each level of severity of the latent antisocial trait. Dotted line; right axis = standard error of estimation for each level of severity of the latent antisocial trait.