Associations between subjective well-being and subcortical brain volumes

Area of Science:

• Neuroscience
• Behavioral Genetics
• Psychology

Background:

• Individual differences in subjective well-being (SWB) are influenced by complex biological and environmental factors.
• Subcortical brain volumes are potential neural correlates of psychological traits, including SWB.

Purpose of the Study:

• To investigate the association between SWB and subcortical brain volumes.
• To explore potential causal pathways and genetic/environmental contributions to SWB-brain associations.
• To examine the relationship using a large dataset of twins and siblings.

Main Methods:

• Neuroimaging and genetic analyses were performed on 724 twins and siblings.
• Mendelian Randomization (MR) was used to probe for causal pathways.
• Twin modeling and linkage disequilibrium (LD) score regression were employed to estimate genetic and environmental influences.

Main Results:

• SWB was associated with hippocampal volumes, but not with volumes of the basal ganglia, thalamus, amygdala, or nucleus accumbens.
• The SWB-hippocampus relationship was nonlinear, with lower SWB linked to smaller hippocampal volumes.
• MR, twin modeling, and LD-score regression found no significant genetic correlations or causal pathways.

Conclusions:

• Low SWB is associated with smaller hippocampal volume, suggesting a neural correlate.
• Genetic factors are not significantly important in the observed SWB-hippocampus relationship.
• Environmental factors, potentially stress and stress hormones, may mediate the association between SWB and hippocampal volume.