Impact of Childhood Adversity and Premorbid Personality on the Onset and Course of Major Bipolar Disorder

Abstract

Background:

Clinical studies have demonstrated the great clinical relevance of long-term depression (LTD). Our study aims to characterise long-term bipolar disorder (LTBP) in comparison with episodic (non-chronic) bipolar major depressive episodes (EBP) on the basis of data from a community sample.

Method:

The Zurich Cohort Study is a prospective study of young adults followed from age 20/21 to 40/41 with six interviews. The stratified sample consisted of two thirds high scorers and one third lower scorers on the Symptom Checklist-90 R (SCL-90-R). LTBP, which was assessed from age 27/28 to 40/41, was defined as threshold or subthreshold depressive syndrome plus hypomanic symptoms, present for more days than not over the past year, plus work or social impairment.

Results:

The cumulative incidence of LTBP was 6.3%, and of episodic BP 15.3%. The two groups did not differ in mean age of onset (13.7 vs. 13.1 years). Age of onset was significantly earlier in subjects with a positive FH of depression and was inversely correlated with the somatisation score of the SCL-90R as assessed at age 19/20. The age of onset increased with increasing levels of childhood family problems in subjects with a positive FH, but decreased in subjects without an FH of depression. Chronic BP was associated with early childhood adversity and low self-esteem and, at a trend-level, with no family history of depression.

Conclusions:

The results are surprising and counter-intuitive, a genetic disposition seeming to be correlated more with periodicity than with chronicity.