Thursday, 17 November 2011

We Need to Talk About Kevin, Genetics of Postnatal Depression and Puerperal Psychosis

Throughout the film We Need to Talk About Kevin there is the question of whether the mother, Eva, was in anyway 'at fault' for the atrocities performed by her son Kevin, or whether Kevin was just born evil. This, of course, can direct us to the sometimes over-used and possibly unhelpful Nature/Nurture divide. Leaving debates of this divide aside, though, there is a strong suggestion that Eva suffered from some sort of postnatal depression, and it is from this perspective that I will discuss my research. Within the department of ‘Psychological Medicine and Neurology’ at Cardiff University we are interested in identifying genes that cause susceptibility to a range of psychiatric disorders. My area of research interest is mood disorders, including bipolar disorder, major depressive disorder and postpartum psychosis.

It is important to point out that these psychiatric disorders are known as ‘complex disorders’, by which I mean that there is not a single causal gene, rather it is interplay of many genes and environmental factors together: nature and nurture together if you like. By identifying susceptibility genes we hope to understand the biology of these disorders which would ultimately provide better treatment, (although this may take years from the identification of genes to treatment) and aid in risk assessment for individuals.

Mood symptoms frequently occur during pregnancy and postpartum periods (after birth), known as postnatal depression or the more severe psychotic form, puerperal psychosis or postpartum psychosis. These are serious mood disorders and do differ from the baby blues, which are often mild, transient and present within the first few days after delivery.

Why do we think that genes are involved in mood disorders? Twin and family studies suggest that there is a genetic contribution to mood disorders including postnatal depression and puerperal psychosis. It is known that women with a family history of such disorders are at a higher risk of experiencing such episodes themselves than women without a family history.

Postnatal depression occurs following around 10% of deliveries. It is known that women with a history of depression and those who experience depression or anxiety during pregnancy are at a greater risk of developing postnatal depression. Puerperal psychosis is more complex, with a wide range of symptoms that can rapidly change. It represents some of the most severe episodes of illness seen in psychiatry and in tragic cases can lead to suicide or, very rarely, harm of the baby. Approximately, 1 in 1000 women after giving birth develop puerperal psychosis, which rises considerably for those women with a history of bipolar disorder. For women with a history of bipolar disorder 50% go on to develop a mood disorder postpartum.

Further episodes of illness are common for women who have suffered a mood disorder after giving birth. It is important to point out that this in not just after having another child, but non-postpartum episodes can also occur. For example, research has suggested that 63% of women who experience puerperal psychosis suffer a subsequent affective mood episode outside of childbirth, whilst approximately 57% experience a relapse after a subsequent pregnancy. Informing women of such statistics allows them to make important decisions regarding having additional children.

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