Correlations with frontal lobe functions as evaluated by trail making test in a sample of patients with probable DSM-5 disruptive mood dysregulation disorder

Objective: Disruptive Mood Dysregulation Disorder (DMDD), a novel diagnosis listed in DSM-5, is characterized by severe, impairing, developmentally inappropriate temper outbursts out of proportion to triggers. It is thought to be related to Depressive Disorders. As a new entity, the neuropsychological characteristics of patients still have not been elucidated. Here, we aim to present correlations of frontal lobe tests with clinical features among cases with probable DMDD.

Methods: Records of 6074 patients at the study center between May 2011 and 2013 were screened for presenting complaints; 600 patients complaining of “irritability” and “temper tantrums” were identified. After eliminating patients with incomplete/missing data and those <6 year-old, 200 patients remained. Patients were evaluated at application with the Childhood Mania Rating Scale (CMRS), Parent Version of the Young Mania Rating Scale (P-YMRS), the Children’s Depression Inventory and the Screen for Anxiety and Related Disorders along with the Atilla Turgay Scale. To differentiate those with probable DMDD, patients with a P-YMRS score of <20 (below cutoff), CDI <19 (below cut-off) and those with <4 criteria endorsed as “frequent” or “very frequent” in the ODD section of AT-Parent and AT-Teacher were selected. Twenty-one (21.2%) of the patients were evaluated with Trail Making Test A and B (TMT-A and TMT-B) at baseline evaluation. Partial correlation analysis controlling for gender and age was used to determine relationships between TMT-A and B tests and CMRS, P-YMRS, AT-Parent, AT-Teacher, CGI, CDI and SCARED scores. P was set at 0.05. All comparisons were two-tailed.

Results: Twenty-one patients (66.7% male) with a mean age of 11.3 years (SD 1.6) were evaluated. Patients with baseline TMT were in higher grades (p=0.03) and tended to get higher score of WISC-R (p=0.08) when compared with those without. Otherwise, CMRS, P-YMRS, CDI, SCARED, CGI-S and AT-Parent and Teacher scores did not differ. Male and female patients did not differ in terms of their ages or psychometric tests including TMT-A and B durations and errors. Median CGI-S for the whole sample was 4.0 (Moderate) with no significant difference between genders. Other baseline psychometric evaluations did not differ according to gender. Partial correlation analysis controlling for gender and age revealed that durations to complete TMT-A and B forms correlated negatively with disorder severity (CGI-S) and subjective anxiety symptoms as reported by SCARED.

Conclusion: Patients were in their majority male, moderately impaired, and there was no statistically significant difference between genders. Partial correlation analyses revealed that those with more severe disorders completed the TMT-A form in a significantly longer time. Those with higher anxiety symptoms tended to complete the TMT-B form in a significantly longer duration. Although retrospective design precludes hypotheses about causation, it may be judged that TMT-A as a more basic test may be affected more by global disorder severity while TMT-B tapped the performance anxiety dimension better, leading to an inverse correlation with SCARED scores. Our results should be replicated with further, longitudinal studies involving larger samples.