“Little is known about the factors that influence persistence of subthreshold expression of bipolar psychopathology,” explain Marieke Wichers (Maastricht University, The Netherlands) and team.
They add: “Insights into the causes of persistence would facilitate the identification of subjects at risk in an early stage of the development of psychopathology and make early intervention possible.”
The researchers therefore assessed data from the Early Developmental Stages of Psychopathology study (EDSP) on 705 young people from Munich, Germany, who were aged 14-17 years at baseline.
The participants were interviewed at baseline and at regular intervals over an average followup period of 8.3 years using the Munich-Composite International Diagnostic Interview (DIA-X/M-CIDI), an updated version of the World Health Organization’s CIDI version 1.2.
Mood symptoms were assessed using 28 items of the DIA-X/M-CIDI depression and dysthymia section and 11 items of the DIA-X/M-CIDI mania section.
In total, 46 participants had mania symptoms at baseline and follow-up, and of the participants without mania symptoms at baseline, 79 developed such symptoms over followup.
Analysis revealed that the onset of mania symptoms over followup was significantly associated with cannabis use (use of the drug on at least five occasions), at an odds ratio (OR) 4.26, and novelty seeking, at an OR of 3.47.
However, none of the risk factors assessed, including family history of (hypo)mania, attention-deficit hyperactivity disorder (ADHD), and experience of trauma, were significantly associated with persistence of mania symptoms. Novelty seeking predicted only transient mania symptoms.
Regarding depression symptoms, 107 participants had such symptoms at baseline and followup, and of those without depression symptoms at baseline 82 developed such symptoms over followup.
Onset of depression symptoms was associated with a family history of depression, while persistence of such symptoms was associated with ADHD and harm avoidance. Of note, a family history of depression and trauma predicted a transitory course of such symptoms.
Wichers and team conclude in the journal Acta Psychiatrica Scandinavica: “Different risk factors may operate during onset and persistence of subthreshold mania and depression.
“The differential associations found for mania and depression dimensions suggest partly different underlying mechanisms.”