Parental reflective functioning (PRF) refers to the capacity of caregivers to reflect upon their children’s internal mental states and intentions, which is seen as crucial for parental sensitivity, defined as the adequate behavioral response to an infant’s signals. In this study, the effect of maternal PRF on sensitivity during the mother–infant interaction was examined in a clinical sample of 50 mothers who were experiencing postpartum depression and their infants aged three to 10 months. Mother and infant were exposed to emotional distress using the still-face procedure. It was hypothesized that low levels of PRF are associated with a decrease in maternal sensitivity in response to distress. Maternal PRF was assessed using the parental reflective functioning questionnaire (PRF). The subscales measured interest and curiosity in mental states, certainty about mental states (i.e., the recognition of the opacity of mental states), and pre-mentalizing modes (i.e., non-mentalizing modes), whereas sensitivity was evaluated using the maternal behavior Q-sort (Mini-MBQS-V). The results revealed a significant overall decrease in maternal sensitivity. As expected, the higher the scores on the pre-mentalizing modes, which indicated low levels of mentalizing through the mothers’ repudiation or defense against it, the greater the decreases in sensitivity. No effects with respect to the interest and curiosity in mental states or the certainty about mental states were found. Our findings determined that the pre-mentalizing modes are predictive of sensitivity to distress in mothers with postpartum depression
