Maladaptive mood repair, atypical respiratory sinus arrhythmia, and risk of a recurrent major depressive episode among adolescents with prior major depression.

BACKGROUND: Because depressive illness is recurrent, recurrence prevention should be a mainstay for reducing its burden on society. One way to reach this goal is to identify malleable risk factors. The ability to attenuate sadness/dysphoria (mood repair) and parasympathetic nervous system functioning, indexed as respiratory sinus arrhythmia (RSA), are impaired during depression and after it has remitted. The present study therefore tested the hypothesis that these two constructs also may mirror risk factors for a recurrent major depressive episode (MDE). METHOD: At time 1 (T1), 178 adolescents, whose last MDE had remitted, and their parents, reported on depression and mood repair; youths' RSA at rest and in response to sad mood induction also were assessed. MDE recurrence was monitored until time 2 (T2) up to 2 years later. Mood repair at T1 (modeled as a latent construct), and resting RSA and RSA response to sadness induction (RSA profile), served to predict onset of first recurrent MDE by T2. RESULTS: Consistent with expectations, maladaptive mood repair predicted recurrent MDE, above and beyond T1 depression symptoms. Further, atypical RSA profiles at T1 were associated with high levels of maladaptive mood repair, which, in turn, predicted increased risk of recurrent MDE. Thus, maladaptive mood repair mediated the effects of atypical RSA on risk of MDE recurrence. CONCLUSIONS: This study documented that a combination of behavioral and physiological risk factors predicted MDE recurrence in a previously clinically referred sample of adolescents with depression histories. Because mood repair and RSA are malleable, both could be targeted for modification to reduce the risk of recurrent depression in youths.

Association of the GABRD gene and childhood-onset mood disorders.

The chromosome 1p36 region was previously indicated as a locus for susceptibility to recurrent major depressive disorder based on a linkage study in a sample of 497 sib pairs. We investigated the gamma-aminobutyric acid A (GABA(A)) delta receptor subunit gene, GABRD, as a susceptibility gene to childhood-onset mood disorders (COMD) because of substantial evidence implicating GABAergic dysfunction in mood disorders and the position of this gene near the 1p36 linkage region. Using a sample consisting of 645 Hungarian families with a child/adolescent proband diagnosed with a mood disorder with the onset of the first episode before age 15, we found some evidence for the association of two polymorphisms located within the gene, rs2376805 and rs2376803, as well as significant evidence for biased transmission of the haplotypes of these two markers (global chi(2) test for haplotypes = 12.746, 3 df, P = 0.0052). Furthermore, significant evidence of association was only observed in male subjects (n = 438) when the results were analyzed by sex (chi(2) = 9.000 1 df, P = 0.003 for rs2376805). This was in contrast with the previous linkage findings, as LOD scores exceeding 3 were only in female-female pairs in that study. These findings point to the GABRD gene as a susceptibility gene for COMD; however, this gene may not explain the previous linkage finding.