In the past year I have cared for a larger number of women who became pregnant than is usually the case. In the last week a particularly challenging patient returned to the practice after a long absence. She was five month pregnant and expressed substantial worry that she would suffer a postpartum depression as she had after one of her previous deliveries. While she was not on any medications during the five months of this pregnancy, she wondered about starting medications several weeks or a month before her due date to forestall the development of depression. This is a strategy she had read about on the internet.
This started me thinking about the current diagnostic protocol for this disorder. DSM-5 does not recognize postpartum depression or psychosis as distinct disorders. Instead they call for the diagnosis of depression, mania, or other disorder with or without psychosis in the peripartum period. The reason for this change is simply that one half of all depressions start during pregnancy and the other half within four weeks of delivery.
The prevalence of postpartum blues in the population is about 65% and postpartum depression is 12%. Postpartum psychosis is considerably rarer with a prevalence of 0.1 to 0.2%. In women who have previously been diagnosed with schizophrenia or bipolar I disorder, postpartum psychosis occurs in about 30%. The risk of developing postpartum psychosis is affected by multiple factors. Probably the two most important are a family history of postpartum psychosis, family history of bipolar disorder, and prior episodes of postpartum psychosis or psychosis unassociated with giving birth. Other significant factors include being off a mood stabilizer, sleep deprivation, and obstetrical complications.
An acute change in the mental status of a postpartum woman requires prompt and careful evaluation both of the patient's medical condition or medical complications and of psychiatric syndromes. The clinical presentation can include disorientation, impaired concentration, agitation, restlessness, incoherent or rambling speech, delusions especially about the infant, hallucinations often commanding and often very unusual, and suicidal thinking. This is a definite psychiatric emergency and requires prompt and effective care. It should not be forgotten that the incidence of suicide in such women is 5% and of infanticide is 4%. Therefore involving the family and educating them about the illness is necessary to get them shoulder what could well be a substantial burden.