These findings underscore several crucial points. ESM appear to be a common concern in outpatient psychiatric settings, consistent with emerging literature about the relatively high rate of manic symptoms in other studies. Second, ESM are associated with substantially increased rates of bipolar disorder, which is why measures assessing ESM may prove useful as screening aids.17, 36
Third, ESM are associated with other, non-bipolar diagnoses, and/or may be a marker of severe pathology rather than a specific marker of a bipolar diathesis.
In the 707 children and adolescents of the LAMS cohort, the diagnoses most frequently assigned at baseline were: ADHD (76.1%), other disruptive behavior disorders (51.1%), mood disorders (40.5%) and anxiety disorders (31.3%). Further, the entire cohort had high rates of comorbidity. Of note, the ESM+ group met criteria for more diagnoses and had poorer overall functioning than the ESM− group. Furthermore, preliminary results indicate that ESM+ youth with BPSD have lower overall functioning, more psychiatric hospitalizations, and more parents with elevated mood compared to ESM+ youth without BPSD.
Similar to the children described by Carlson & Kelly,6
many youth who were identified as experiencing ESM did not meet diagnostic criteria for BPSD. Whether or not these children with ESM will eventually develop a bipolar diagnosis, either confirming or refuting the findings of Lewinsohn et al.10
and Hazell et al.8
that no or few youth with manic symptoms will later develop BPSD, will be assessed through longitudinal assessments of this study cohort. This question is a key specific aim of the LAMS study.
As expected, there were some differences in rates of diagnoses between the ESM groups. For instance, ESM+ youth were diagnosed with more bipolar spectrum disorders than those in the ESM− group. However, only one-quarter of youth with ESM actually met diagnostic criteria for a bipolar spectrum disorder. (Interestingly, most of that quarter of ESM+ children with BPSD met diagnostic criteria for either BP-NOS (48%) or BP1 (43%), with very few meeting criteria for BP2 or cyclothymia.) ESM+ youth were, in fact, more likely to have a disruptive behavior disorder diagnosis than a bipolar diagnosis. More specifically, over half of the ESM+ group was diagnosed with a disruptive behavior disorder, primarily ODD, compared to only 36% of the ESM− group.
The ESM+ and ESM− groups did not differ significantly in the number of youth currently diagnosed with a depressive disorder, ADHD, or anxiety disorder. Despite this lack of categorical differences between groups, parents of children in the ESM+ group endorsed significantly greater depressive, ADHD, and anxiety symptoms on the CAASI-4R and SCARED compared to the ESM− group. This suggests the ESM+ group is more symptomatic across a variety of domains even if these symptoms do not (yet) translate to significantly more diagnoses within those domains.
With such diagnostic diversity found in the ESM+ group, it may be argued that the PGBI-10M cut score was set too low. However, the PGBI-10M cut score of 12 for the ESM groups was purposely set to keep sensitivity to true bipolar cases high, and also capture a large number of other cases showing similar symptoms for different diagnostic reasons. The second, heterogeneous group will be the more interesting one to follow longitudinally.
Not surprisingly, with over three-fourths of LAMS participants meeting diagnostic criteria for ADHD, stimulants were the most frequently prescribed class of current and past medication. However, with 76% of the overall sample having an ADHD diagnosis, only 39% of the LAMS cohort was currently prescribed a stimulant. Antipsychotic medications were prescribed at a relatively high rate, with nearly a quarter (22%) of all 707 LAMS participants prescribed an antipsychotic at the time of assessment. Although ESM+ and ESM− groups differed in the rates of bipolar spectrum disorders and disruptive behavior disorders, neither current nor past exposure to any medication class examined in this study differed significantly between the groups. However, when examining the ESM+ group, those children with BPSD were prescribed significantly more antipsychotics (41% vs. 17%), anticonvulsants, and mood stabilizers compared to ESM+ participants without BPSD. Finally, although approximately 30% of the participants were diagnosed with an anxiety disorder and 18% of the youth met criteria for a depressive disorder, rates of current selective serotonin reuptake inhibitor (SSRI) prescriptions were relatively low (8.9%). This modest rate may reflect the effect of the Black Box warning for SSRIs.37
A more detailed examination of community-based prescribing practices is warranted in future examinations of the LAMS study sample.
When examining the ESM+ group, the fact that the children without a bipolar disorder had a greater rate of disruptive behavior disorders (DBD) supports the possibility that there are two main paths that lead to ESM+ : (a) having a bipolar disorder, (b) having DBD and some mood symptoms without meeting diagnostic symptoms criteria for a bipolar disorder.
Limitations of this study include the fact that the sample of children was obtained only from outpatient mental health centers associated with university partners. Therefore, the sample does not include children whose parents sought care in other settings or who were currently hospitalized. The sample was focused in Ohio and Western Pennsylvania and might not reflect outpatient mental health services utilization patterns in other regions. Further, given that these were all children and families seeking care, they are not representative of the general population of children.
Although ESM may be commonly found in children and adolescents, this does not necessarily indicate that BPSD is common in youth. In fact, the children and adolescents in the ESM+ group were more likely to have an ADHD and/or disruptive behavior disorder rather than a BPSD. Screening for ESM did increase the base rate of BPSD to a quarter of the sample, however, higher than would be anticipated in a general outpatient clinic.38
In conclusion, although LAMS participants were selected based on the presence of ESM, their subsequent structured interviews revealed a diverse range of psychiatric disorders. Furthermore, while ESM were associated with higher rates of BPSD, most of these youth did not meet diagnostic criteria for BPSD. Rather, ESM+ youth more commonly had a disruptive behavior disorder. Perhaps most surprising is the fact that the ESM+ youth did not differ from ESM− in number of psychotropic medications, a finding that warrants further investigation. The data will provide the opportunity to examine medication use in youth with considerable psychiatric morbidity. Results suggest the longitudinal assessment of ESM is needed to examine which factors are associated with diagnostic evolution to a bipolar spectrum disorder in patients with ESM+, and whether such evolution even occurs. Longitudinal data are also needed to identify risk and protective factors associated with long-term outcomes in this vulnerable population.