This study complements the existing research examining mental health problems in young children. It is only the fourth study [3
] to examine rates of parent-reported DSM disorders in non-specialty clinic referred preschoolers using a comprehensive diagnostic interview, and includes a larger number of children than all studies except Lavigne et al. [3
We found that a substantial number of children (27.4%) met standard PAPA/DSM-IV criteria within the past 3 months. ODD, specific phobia, and SAD were the most prevalent disorders; depression, selective mutism, and panic disorder were the least prevalent. Although it is difficult to compare rates of disorders across studies with varying methods, the rates of specific disorders in this study were consistent with, although at the higher end of the range of, previous studies with samples of non-specialty clinic referred preschoolers (see ) [3
]. However, we assessed a greater number of emotional disorders than other studies, hence it is not surprising that higher rates were observed for any emotional disorder and any diagnosis. The rate of ADHD (2.0%) was consistent with, although at the lower end of the range of, previous studies (2.0-12.8%). It is possible that the inclusion of older preschool-aged children in other samples accounts for this difference as symptoms of ADHD may be easier to recognize as children are required to function in a greater number of, and more demanding, contexts.
It is noteworthy that ODD, specific phobia, and SAD had the highest rates, as some degree of fear and oppositional behavior are normative during the preschool period. Following Egger et al. [39
], we attempted to address this issue by counting ODD and SAD symptoms for the diagnosis only if they fell in the top 10% of the distribution on frequency of occurrence. However, the 10% cutoff is admittedly arbitrary. When we applied a 5% cutoff, the rate of ODD dropped substantially, going from 9.4% to 4.1%. In contrast, the change in the rate of SAD was much smaller, decreasing from 5.4% to 4.6%. Hence, the effect of changing cutoffs varies for different disorders. Further work is needed to establish empirically-based cutoffs.
Similar to older youth and adults, there was considerable overlap between disorders: 9.2% of children met criteria for two or more diagnoses. This falls at the high end of the range in other studies (5.4-8.0% [3
]. As noted above, this likely reflects the greater number of disorders assessed in this study. We examined the associations between the four major classes of disorders at both the diagnostic and the symptom dimension level. In both sets of analyses, there was significant comorbidity/covariation between depression, anxiety, and ODD, and between ODD and ADHD. However, ADHD was associated with depression only in the dimensional analysis, and was not associated with anxiety at either the diagnostic or dimensional level. The magnitudes of the associations decreased somewhat after controlling for comorbidity with other disorders, but the pattern remained similar.
Consistent with other studies of preschoolers, there was considerable overlap between emotional and behavior disorders [7
]. We are aware of only one similar study that reported rates of comorbidity among specific disorders [3
]. They also found the highest degree of comorbidity between ODD and ADHD. Unlike our study, they found an association between ADHD and depression diagnoses; however, they assessed very few internalizing disorders, so other patterns of comorbidity cannot be compared. Consistent with studies of older children [54
] the magnitudes of the associations between disorders in this study were the largest between ADHD and ODD, then depression and anxiety, and then depression and ODD. The association was the lowest between ADHD and anxiety. In addition, the magnitude of the relation between depression and anxiety was very similar to that between depression and ODD, which has been found in older children as well [54
]. The association found between depression and anxiety suggests that this comorbidity that is identified regularly in adults [e.g., 55
] is evident as early as the preschool period.
The finding that ODD was comorbid with all of the other major groups of disorders examined in the study (with the exception of anxiety disorders when controlling for other diagnoses) is consistent with previous research with preschool-aged children [8
], and with longitudinal studies finding that oppositionality is an antecedent of virtually all forms of psychopathology in preschoolers [11
] and adolescents and adults [56
]. These findings might be explained by recent research in older children indicating that ODD includes several distinct components that have more specific associations with other disorders both cross-sectionally [58
] and longitudinally [59
]. Thus, ODD appears to include an irritability dimension that is associated with some emotional disorders, a headstrong dimension that is associated with ADHD, and a hurtful dimension that is associated with both ADHD and conduct disorder [59
PAPA diagnoses and symptom scores were associated with psychosocial functioning on the CGAS and Vineland Socialization scale, as well as with mental health treatment. Overall, ODD and ADHD had the largest associations with each functioning measure. These results are consistent with previous findings that 5-year-olds with externalizing psychopathology were more likely to be rated as impaired than children with internalizing psychopathology [40
]. Also consistent with studies of preschoolers [39
], older youth [54
], and adults [55
], children with multiple disorders exhibited poorer psychosocial functioning on the CGAS than children with a single disorder.
With a few exceptions, diagnoses were not associated with demographic variables. Studies with older children [e.g., 61
] and those using checklist measures in preschoolers [10
] suggest that demographic variables such as minority status, male sex, and lower socioeconomic status are associated with emotional and behavioral problems in children, but few preschool researchers have examined these correlates in relation to specific disorders. Researchers have reported that preschool-aged boys are more likely to be diagnosed with ADHD than girls [3
]. In the present study, more boys (n
= 8/11) met criteria for ADHD than girls (n
= 3/11), but this difference was not statistically significant, X2
= 541) = 1.53, p
= .22. Other demographic correlates such as race and age do not appear to be associated with diagnoses in preschoolers [3
], but the research is fairly limited.
This study builds on other recent studies suggesting that the DSM-IV criteria can be applied to young children [e.g., 3
]. However, a number of issues require further consideration. First, as noted above, many symptoms are similar to normative behaviors, and there is currently no consensus about how to make this distinction [8
]. For example, the rate of ODD in this study was higher than in studies of school-age children [61
]. In addition, there is evidence that many young children “outgrow” their fears with age [63
]. Thus, some of the children in our sample who qualified for diagnoses of ODD, specific phobia, and SAD may be exhibiting transient problems that, despite being associated with impairment, could arguably be considered to fall at the high end of the normative range for this age. If so, it may suggest that current diagnostic criteria require modification for preschoolers. Longitudinal studies are needed to determine whether DSM-IV diagnoses in early childhood remain stable through subsequent developmental periods, remit completely, or persist at a subthreshold level, possibly conferring risk for later escalation to full-threshold disorders.
Second, the concept of psychosocial functioning can be problematic in preschoolers. Three-year-olds have relatively few activities and relationships in which to exhibit poor functioning. Moreover, parents vary in their tolerance of, and response to, problem behavior, which can influence both the reporting and level of psychosocial functioning.
Finally, many internalizing disorder symptoms reflect subjective states (e.g., sadness, worry). As many preschoolers cannot articulate these feelings, assessments must rely on adults’ inferences.
4.1 Strengths and Limitations
This study has several significant strengths. This is one of very few studies to examine rates of DSM-IV disorders in a large community sample of preschoolers. In addition, we used a comprehensive, interviewer-based diagnostic interview that was specifically designed to assess emotional and behavioral disorders in preschool-aged children.
However, this study has also had a number of limitations. First, our data were based on parents’ reports, and did not incorporate data from other informants or direct observations of the child. In addition, the same source was used to assess both child disorders and psychosocial functioning, hence these associations may be inflated due to shared method variance.
Second, the correspondence between PAPA diagnostic thresholds and clinical judgments of caseness are unclear. While this is a general issue in psychiatric epidemiology, it may be even greater for preschool emotional and behavioral disorders where understanding and conventions regarding diagnostic criteria and boundaries are less developed.
Third, we focused on a narrow age group within the preschool period (three-year olds). While this provides more reliable estimates of rates of disorders in this age band, further work is needed to determine whether these rates differ at ages four and five.
Fourth, interviews were conducted by telephone, which has, to our knowledge, never been done with the PAPA before. However, in epidemiological studies of adult psychopathology, telephone interviews are common, and concordance between telephone and face-to-face interviews is high [64
Fifth, we used the ECI screener for ADHD and ODD to reduce administration time for the first 60% of the sample. However, given the interviewers’ confirmation of all negative ECI screeners, the false negative rate was probably quite low. In addition, the rates for ADHD and ODD were fairly comparable for the first 60% and latter 40% of the sample, and results were similar when analyses were limited to the subsample that received the complete PAPA ADHD and ODD sections. Nonetheless, the dimensional measures of ADHD and ODD must be regarded with caution.
Sixth, given the small number of cases of major depression/dysthymia, cases of depression NOS were included in the “any depression” category.
Seventh, interrater reliability was assessed using a small (n = 21) number of interviews, and the use of audiotapes may produce high-end estimates. Eighth, many analyses were conducted, particularly with demographic variables, so it is possible that some of these results may be attributable to chance.
Ninth, the sample was not randomly ascertained, and the use of commercial mailing lists may introduce unknown biases. However, the demographic characteristics of the sample tended to mirror the community in which the study was conducted. Unfortunately, there is no economically feasible method to obtain representative samples of preschoolers in the United States. Thus, the best approach at this time may be to use a variety of recruitment procedures to triangulate on estimates of the rates of disorders in the community.
Finally, the sample was largely white and middle class, and the small number of children in racial/ethnic minority groups may limit the power to detect differences in rates of disorders and symptoms. Further work is needed to examine the rates of preschool emotional and behavioral problems in more diverse samples.
4.2 Conclusions and Implications for Research and Practice
When PAPA/DSM-IV criteria are applied to parent-reports of emotional and behavioral problems in preschoolers, rates of diagnoses and comorbidity appear to be relatively high, and symptoms are associated with poorer psychosocial functioning. These data are consistent with research on older youth. Although the meaning of these rates requires further elucidation, these findings suggest that parents, teachers, treatment providers in pediatric settings, and policy makers should be alert to the possibility that preschoolers may be experiencing clinically significant symptoms. Future research should include longitudinal studies to assess the stability of DSM disorders in young children as well as studies that incorporate multiple informants (e.g., both parents, teachers/child care providers) and measures (e.g., interviews, child observation). In addition, more normative data on preschoolers’ behaviors are needed to discern the boundary between typical and problematic levels of symptoms [5