Researchers in the UK are hoping to isolate a recessive gene that they believe is linked with postpartum psychosis, a rare and extreme form of postnatal depression. By identifying the gene, experts hope that they can help doctors identify women likely to develop postpartum psychosis and offer effective treatment. A separate study also found that a quarter of women who experience mild euphoria after childbirth can develop late-onset postnatal depression within two months. [Guardian]