The nature of the temporal relationship between psychological factors and mood episodes is unclear. The objectives of this study were to determine if temperament and self-esteem predict the onset of mood episodes, and if prior mood episodes influence the stability of these factors over time in high-risk offspring of bipolar parents.
Offspring of a parent with bipolar disorder participating in the Flourish Prospective Offspring Study were clinically assessed repeatedly using semi-structured KSADS-PL/SADS-L format interviews, and completed repeated measures of self-esteem, and temperament. Shared frailty survival models and mixed effects regression models were used to determine if psychological factors predicted incident mood episodes, and whether these factors change over time after the incident mood episode, respectively.
Emotionality, shyness and self-esteem were not associated with the hazard of incident major depression; however, increased activity reduced the hazard of this outcome (hazard ratio [HR]: 0.51; 95% CI: 0.27, 0.98). Emotionality and shyness scores increased, while sociability, activity and self-esteem scores decreased after the incident major depressive episode (emotionality: mean change [MC]: 0.35, p = 0.0289; shyness: MC: 0.40, p = 0.0196; sociability: MC: -0.49, p = 0.0001, activity: MC: -0.32, p = 0.0001; self-esteem: MC: -0.79, p = 0.001).
Psychological measures were based on self-report and some models had low numbers limiting the numbers of covariates included as potential confounders.
Among the assessed temperamental dimensions, activity showed a protective effect for major depressive episode onset suggesting this temperamental characteristic could serve as a protective target in high risk youth. Conversely, all assessed psychological factors shifted towards increased vulnerability after the first depressive episode.