This study used an actor–partner interdependence model to assess the relationship between differentiation of self
and family functioning in a sample of 118 heterosexual Spanish couples, with additional attention to family structural
correlates, including age of the children, number of children in the household, and educational level. Results showed
a significant actor effect, with greater differentiation of self levels predicting better family functioning within individuals.
Implications for mental health professionals regarding differentiation are provided.
