Postpartum psychosis (PP) is the most severe psychiatric disorder associated with childbirth. Previous evidence has shown gene expression alterations in immune profile in women with PP when compared with healthy postpartum women. However, no study has ever evaluated women at risk who do not develop the disorder.

We conducted an exploratory analysis of a gene expression profile that could distinguish women with PP episode (PPE) from women at risk who do not develop PP (NPPE) after delivery.

The sample was characterised by 24 women at risk of PP of which n=12 with PPE and n=12 with NPPE and 21 healthy women in the same postpartum period. Following Microarray analysis, we assessed gene expression signature across the 3 groups using ANOVA. We then studied Pathway analysis of genes differently expressed in PPE and PPE exploring canonical pathways and upstream regulators using Ingenuity Pathway Analysis software.

Following an exploratory gene expression analysis we identified 719 genes that are differently expressed across PPE and NPPE. The PPE presented upregulation of several genes involved in the inflammatory pathway and increased gene expression levels of GRIA4, AKT3, SP4 and NRG1 genes, which have been previously described in psychotic disorders. Moreover, 5 differently expressed canonical pathways were identified including ones relevant to development, mitochondrial formation and immune system.

These preliminary results reveal the presence of an immuno-neuro-endocrine dysregulation in postpartum psychosis, with an upregulation of the immune system specific to those women at risk who actually develop postpartum psychosis episodes.