In January, an excellent review of postpartum psychosis by Perry et al. was published in Brain Sciences, in which the authors describe clinical symptoms, risk factors, and potential underlying causes of the illness. This post will highlight key points of the review, which included 105 publications. Please find the citation at the end of this post.
Postpartum psychosis is a severe psychiatric illness requiring emergency medical attention, occurring in about one delivery out of every thousand. Currently, there are no uniform diagnostic criteria for postpartum psychosis; however, patients with postpartum mood episodes featuring psychotic symptoms, such as delusional thinking, hallucinations, and disorganized behavior are commonly diagnosed with postpartum psychosis. The authors additionally consider postpartum mania without psychotic symptoms to fall under the diagnostic umbrella of postpartum psychosis.
· Postpartum psychosis typically begins suddenly and shortly after delivery, usually within one to two weeks. Mood symptoms are often prominent, with new mothers mostly experiencing either mania or mixed (e.g., both manic and depressive) symptoms, though some experience only depressed mood. Classically, in patients who experience depressed mood without manic symptoms, psychotic symptoms must also be present to qualify for a diagnosis of postpartum psychosis.
· Over 70% of women with postpartum psychosis experience psychotic symptoms. Delusions of persecution and ideas of reference are particularly common.
· Visual hallucinations may be seen more often in postpartum psychosis than other psychotic illnesses.
· Delusions, when present, often have to do with the infant. Depending on the specific delusion, protective or abusive behavior toward the infant may result.
· Infanticide is relatively rare, occurring in an estimated 1-4.5% of cases.
· The postpartum period is a time of exceptionally high psychiatric risk, with one study finding the risk of psychiatric hospitalization twenty-two times higher in the first month postpartum versus during pregnancy. The relative risk for first-time mothers was even greater at thirty-five times over the risk during pregnancy.
· 40% to 50% of women with postpartum psychosis have no history of psychiatric illness.
· While postpartum psychosis is relatively rare in the general population as described, there is a very strong association between bipolar disorder and postpartum psychosis. Nearly 20% of women with pre-existing bipolar illness go on to develop symptoms of postpartum psychosis after delivery.
· Mothers who have experienced postpartum psychosis are at high risk of future illness, with roughly half experiencing perinatal affective illness in future pregnancies. The risk of developing severe mood or psychotic symptoms is particularly high in mothers with bipolar I disorder.
Potential causes of postpartum psychosis
· The only obstetric predictor of postpartum psychosis which has been clearly associated with postpartum psychosis is primiparity, or first-time birth.
· No psychological or social predictors have been reliably associated with postpartum psychosis.
· Postpartum hormonal shifts may play a role in the development of postpartum psychosis. During pregnancy, there are high levels of estrogen and progesterone, hormones which act both in the brain, impacting behavior, and in the uterus and placenta, maintaining the pregnancy. Levels of these hormones plummet postpartum, likely impacting dopaminergic and serotonergic systems in the brain and causing psychotic and mood symptoms. Indeed, other times of hormonal shifts, such as pre-menstruation and perimenopause represent times of psychiatric vulnerability.
· Postpartum shifts in immune system function may contribute to postpartum psychosis. Circulating levels of cytokines, substances released by cells to modulate the body’s immune system, are elevated during active bipolar illness, particularly manic phases, which commonly occur in postpartum psychosis. Additionally, symptoms of many autoimmune conditions acutely worsen postpartum, mirroring the timing of onset of postpartum psychosis. Finally, other illnesses which may present with psychotic symptoms, such as anti-N-methyl-D-aspartate receptor encephalitis, are the result of immunopathology, suggesting there may be other yet unclear mechanisms by which postpartum psychosis may be triggered.
· Sleep deprivation may be both a risk factor and a symptom of postpartum psychosis, and it seems to be a particular risk in women who have previously experienced sleep deprivation-triggered mania. While more research is needed, patients with postpartum psychosis have been found to experience longer labors and deliver in nighttime hours more frequently than their healthy counterparts.
· Genetic risk factors for postpartum psychosis are under investigation. Multiple associations between personal history of bipolar disorder and family history of postpartum psychosis have been made, with one study identifying areas of risk on chromosomes 8 and 16. Additionally, variation in the serotonin transporter gene has been associated with increased risk of postpartum psychosis in women with preexisting bipolar disorder.
The above risk factors and triggers likely act in concert to confer risk for postpartum psychosis – that is, a genetically at-risk mother may experience shifts in hormones, inflammatory cytokines, and neurotransmitters, collectively precipitating postpartum psychosis. How and how much they contribute to such risk will require further research.
The relative rarity of postpartum psychosis complicates efforts to clearly define its diagnostic features, describe its associated risk factors, and elucidate its underlying causes, as these require study of large numbers of patients.
Answers to these questions form the basis of sound patient education and accurate diagnosis, on which life-saving treatment may be sought and based, underscoring the importance of research efforts to these ends.
Richard Seeber II, MD
Perry A, Gordon-Smith K, Jones L, Jones I. Phenomenology, Epidemiology and Aetiology of Postpartum Psychosis: A Review. Brain Sci. 2021 Jan 4;11(1):47. doi: 10.3390/brainsci11010047. PMID: 33406713; PMCID: PMC7824357.