Microsocial analysis of dyadic interactions with toddlers and mothers with borderline personality disorder

Borderline personality disorder (BPD) is known for disruptions in mother-child interaction, but possible underlying patterns of micro-behavior are barely understood. This is the first study examining behavioral dyadic synchrony—the coordinated and reciprocal adaptation of behavior—and regulation on a micro-level and relating it to macro-behavior in mothers with BPD and their toddlers. Twenty-five mothers with BPD and 29 healthy mothers participated with their 18- to 36-month-old toddlers in a frustration-inducing paradigm. Mother and toddler behavior was continuously micro-coded for gaze, affect, and vocalization. Synchrony, operationalized as the simultaneous engagement in social gaze and positive affect, and (co-)regulative behaviors and their contingencies were analyzed and associated with borderline symptom severity, the overall quality of interaction, and child internalizing and externalizing behavioral problems. Dyads with mothers with BPD showed significantly less synchrony compared to dyads with healthy mothers. Low synchrony was associated with high BPD symptom severity and low overall interaction quality. Dyads with BPD used the same amount of regulative behaviors as dyads with healthy mothers. Though both groups equally responded to children’s negative emotionality, mothers with BPD were less effective in drawing the dyad back into synchrony. For dyads with BPD, regulative behaviors were negatively associated with child externalizing behaviors. BPD symptomology may reduce the effectiveness of mothers’ attempts to attune to their child’s needs. An emphasis on synchrony and regulative behaviors may be an important therapeutic target for parenting programs in mothers with BPD. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00737-023-01346-9.