This study aimed to investigate mother–infant interaction and infant development in women at-risk of postpartum psychosis (PP), with and without a postpartum relapse.

103 women (and their offspring) were included, 43 at-risk-of-PP because of a diagnosis of bipolar disorder, schizoaffective disorder or previous PP, and 60 with no current/previous mental illness or family history of PP. Of the at-risk women, 18 developed a psychiatric relapse within 4 weeks after delivery (AR-unwell), while 25 remained symptom-free (AR-well). Mother–infant interaction was assessed using the CARE-Index at 8 weeks' and 12 months' postpartum and infant development using the Bayley-III at 12 months' postpartum.

Women at-risk-of-PP as a group, regardless of whether they developed a psychiatric relapse within 4 weeks after delivery, had less synchronous mother–infant interactions and had infants with less optimal cognitive, language, motor and socio-emotional development than healthy controls. In particular, boys of at-risk women had the lowest scores in cognitive, language and motor development and in mother–infant interaction, while girls of the at-risk women had the lowest scores in socio-emotional development. The synchrony in the dyad predicted infant cognitive and language development. There was no evidence for a difference in mother–infant interaction nor in infant development between the AR-unwell and AR-well groups.

These results suggest that, while there is a lack of evidence that an early postpartum relapse in women at-risk-of-PP could represent a risk for the infant per se, maternal risk for PP may be associated with less optimal mother–infant interaction and infant development.

Little is known about the effects of depression before birth on the quality of the mother–infant interaction.

To understand whether depression, either in pregnancy or in lifetime before pregnancy, disrupts postnatal mother–infant interactions.

We recruited 131 pregnant women (51 healthy, 52 with major depressive disorder (MDD) in pregnancy, 28 with a history of MDD but healthy pregnancy), at 25 weeks’ gestation. MDD was confirmed with the Structured Clinical Interview for DSM-IV Disorders. Neonatal behaviour was assessed at 6 days with the Neonatal Behavioural Assessment Scale, and mother–infant interaction was assessed at 8 weeks and 12 months with the Crittenden CARE-Index.

At 8 weeks and 12 months, dyads in the depression and history-only groups displayed a reduced quality of interaction compared with healthy dyads. Specifically, at 8 weeks, 62% in the depression group and 56% in the history-only group scored in the lowest category of dyadic synchrony (suggesting therapeutic interventions are needed), compared with 37% in the healthy group (P = 0.041); 48% and 32%, respectively, scored the same at 12 months, compared with 14% in the healthy group (P = 0.003). At 6 days, neonates in the depression and history-only groups exhibited decreased social-interactive behaviour, which, together with maternal socioeconomic difficulties, was also predictive of interaction quality, whereas postnatal depression was not.

Both antenatal depression and a lifetime history of depression are associated with a decreased quality of mother–infant interaction, irrespective of postnatal depression. Clinicians should be aware of this, as pregnancy provides an opportunity for identification and intervention to support the developing relationship.

Mother and Baby Units (MBUs) are usually preferred by patients and clinicians. Current provision is limited, although expansion is in progress. To ensure successful investment in services, outcome measurement is vital.

To describe maternal outcomes, mother–infant outcomes and their relationship in one MBU.

Paired maternal Brief Psychiatric Rating Scale (BPRS) scores, Health of the Nation Outcome Scales (HoNOS) scores and Crittenden CARE-Index (CCI) mother–infant interaction data were collected at admission and discharge.

There were significant improvements in BPRS (n = 152), HoNOS (n = 141) and CCI (n = 62) scores across diagnostic groups. Maternal BPRS scores and mother–infant interaction scores were unrelated. Improvement in maternal HoNOS scores was associated with improved maternal sensitivity and reduction in maternal unresponsiveness and infant passiveness.

Positive outcomes were achieved for mothers and babies across all diagnostic groups. Reduction in maternal symptoms, as measured by BPRS, does not necessarily confer improvement in mother–infant interaction. MBU treatment should focus on both maternal symptoms and mother–infant interaction.

None.