A physical examination and laboratory investigations may disclose somatic illness complicating the obstetric events, which sometimes provokes psychosis. It is important to obtain the case records of previous episodes of mental illness, and, in patients with multiple episodes, to construct a summary of the whole course of her psychiatric history in relation to her life. In the 10th edition of the International Classification of Diseases, published in 1992, the recommendation is to classify these cases by the form of the illness, without highlighting the postpartum state. There is, however, a category F53.1, entitled severe mental and behavioural disorders associated with the puerperium, which can be used when it is not possible to diagnose some variety of affective disorder or schizophrenia. The American Psychiatric Associations Diagnostic and Statistical Manual, whose 5th edition was published in May 2013, allows the use of a peripartum onset specifier in episodes of mania, hypomania or major depression if the symptoms occur during pregnancy or the first four weeks of the puerperium. The failure to recognize postpartum psychosis, and its complexity, is unhelpful to clinicians, epidemiologists, and other researchers. Onset groups
Postpartum bipolar disease belongs to the bipolar spectrum, whose disorders exist in two contrasting forms – mania and depression. They are highly heritable, and affected individuals (less than 1% of the population ) have a lifelong tendency (diathesis) to develop psychotic episodes in certain circumstances. The triggers include a number of pharmaceutical agents, surgical operations, adrenal corticosteroids, seasonal changes, menstruation and childbearing.
In addition, episodes starting after childbirth may be triggered by adrenal corticosteroids, surgical operations (such as Caesarean section) or bromocriptine as an alternative to, or in addition to, the postpartum trigger. Course of the illness
With modern treatment, a full recovery can be expected within 6–10 weeks. After recovery from the psychosis, some mothers have depression, which can last for weeks or months. About one third have a relapse, with a return of psychotic symptoms a few weeks after recovery; these relapses are not due to a failure to comply with medication, because they were often described  before pharmaceutical treatment was discovered. A minority have a series of periodic relapses related to the menstrual cycle. Complete recovery, with a resumption of normal life and a normal mother-infant relationship is the rule.Many of these mothers experience other bipolar episodes, on the average about one every six years. Although suicide is almost unknown in an acute puerperal manic or cycloid episode, depressive episodes later in life carry an increased risk, and it is wise for mothers to maintain contact with psychiatric services in the long term. In the event of a further pregnancy, the recurrence rate is high – in the largest series, about three quarters had a recurrence, but not always in the early puerperium; the recurrence could occur during pregnancy, or later in the postpartum period. This suggests a link between early onset and other onset groups.