Family conflict and somatic symptoms over 10 years: a growth mixture model analysis

While family conflict and somatic symptoms are mutually associated, few longitudinal studies have examined multiple (heterogeneous) trajectory subgroups for family conflict and somatic symptoms and their covariation over time. The aim of this study was to identify heterogeneous trajectory subgroups for family conflict and somatic symptoms and their joint trajectories.

A representative sample of 424 community participants completed surveys at baseline and 1-, 4-, and 10-year follow-ups. Family conflict and somatic symptoms were assessed at each wave. Covariates (age, gender, marital status, education, and medical conditions) were assessed at baseline. Growth mixture modeling (GMM) was used to identify heterogeneous trajectory subgroups for family conflict and somatic symptoms. A parallel process GMM was used to examine joint trajectory subgroup membership between family conflict and somatic symptoms.

There were three trajectory subgroups for family conflict: stable low; worsening; and improving, and three somewhat similar trajectory subgroups for somatic symptoms: stable low; stable moderate; and improving. Family conflict and somatic symptom trajectory subgroup memberships were jointly associated. Individuals who had stable low family conflict were most likely to follow a stable low somatic symptom trajectory. Individuals who improved in family conflict were most likely to continue to have stable low somatic symptoms or improve in somatic symptoms. Moreover, individuals who had stable moderate somatic symptoms were most likely to show worsening family conflict.

This study demonstrates heterogeneous family conflict and somatic symptom trajectories and indicates that these trajectories covary over time.