Mood disorders such as bipolar disorder (BPD) and major depressive disorder (MDD) typically emerge in childhood or adolescence. Now, researchers in Switzerland, the USA and Canada have investigated whether certain other mental health disorders precede the onset of mood disorders. They analysed data from a cohort study involving 449 children of patients with BPD (n=88), MDD (n=71), substance use disorders (n=30) and medical controls (n=60).
The children and adolescents began the study at 10 years old on average, were interviewed using the Kiddie-Schedule for Affective Disorders and Schizophrenia every 3 years, and were followed up for an average of 13 years. The researchers analysed associations between potential precursors and the subsequent onset of manic/hypomanic episodes or MDD (depressive episodes in those who did not experience mania or hypomania). They found that first manic/hypomanic episodes were predicted by earlier depressive episodes, conduct disorder or drug use disorders. These links tended to be stronger in children of parents with BPD compared to those of parents without BPD. Meanwhile, MDD onset was predicted by earlier anxiety disorders.
“Although we found children who presented with depressive episodes, conduct disorder or cannabis use disorders to be at an elevated risk of developing manic/hypomanic episodes, there were still many children with these psychopathological manifestations who did not develop manic/hypomanic episodes”, explain researchers Caroline Vandeleur and Martin Preisig. “As such, even in children of parents with bipolar disorders, the occurrence of depressive episodes, conduct disorder or cannabis use disorders would not yet justify the installation of a preventive treatment with mood stabilizers. However, these children should be closely followed by a clinician and one focus should be the avoidance of drug use”.
Overall, these findings suggest that BPD and MDD might develop via distinct pathways. Now, these findings need replication in larger cohorts of offspring. Clinical studies of treatments and preventive measures in youth with anxiety, behavioural or depressive disorders are also critical to understand what helps reduce the debilitating impact of later mood disorders.
Rudaz, D., Vandeleur, C.L., Gholan, M., Castelao, E., Strippoli, M-P. F., Marquet, P., Aubry, J-M., Merikangas, K.R. & Preisig, M. (2020), J. Child Psychol. Psychiatr. doi: 10.1111/jcpp.13307.