Research has lagged far behind other areas of medicine and psychiatry. There is a dearth of knowledge and of theories. There is a much evidence of heritability, both from family studies and molecular genetics. Early onset cases occur more frequently in first time mothers, but this is not true of late postpartum or pregnancy onset. There are not many other predictors. Sleep deprivation has been suggested. Inhibition of steroid sulphatase caused behavioural abnormalities in mice. A recent hypothesis, supported by collateral studies, invokes the re-awakening of auto-immunity after its suppression during pregnancy, on the model of multiple sclerosis or autoimmune thyroiditis; a related hypothesis has proposed that abnormal immune system processes (regulatory T cell biology) and consequent changes in myelinogenesis may increase postpartum psychosis risk. Aberrant steroid hormone–dependent regulation of neuronal calcium influx via extracellular matrix proteins and membrane receptors involved in responding to the cells microenvironment might be important in conferring biological risk. Another promising lead is based on the similarity of bipolar-cycloid puerperal and menstrual psychosis; many women have had both. Late-onset puerperal psychoses, and relapses may be linked to menstruation. Since almost all reproductive onsets occur when the menstrual cycle is released from a long period of inhibition, this may be a common factor, but it can hardly explain episodes starting in the 2nd and 3rd trimesters of pregnancy. History
Between the 16th and 18th centuries about 50 brief reports were published; among them is the observation that these psychoses could recur, and that they occur both in breast-feeding and non-lactating women.
Out may refer to:

Arts, entertainment, and media
Films
Out (1957 film), a documentary short about the Hungarian Revolution of 1956
Out (1982 film), an American film directed by Eli Hollander
Out (2002 film), a Japanese film based on the novel by Natsuo Kirino and directed by Hideyuki Hirayama
Out (2013 film), a Canadian short comedy film directed by Jeremy LaLonde
Out (2017 film), a Slovak film directed by György Kristóf
Out (2020 film), an American animated film produced by Pixar

Music
Out (jazz) or outside, an approach to jazz improvisation
OUT, a band produced by Adam Walton
OUT, a 1994 album by Nav Katze
Out (In Essence), a 1991 album by Fluke

Television
Out (miniseries), a 1978 British television crime drama starring Tom Bell
"Out" (Dark Angel), a television episode

Other uses in arts, entertainment, and media
Out (magazine), an LGBT fashion, entertainment, and lifestyle magazine
Out (novel), a 1997 novel by Natsuo Kirino
OUTeverywhere, a community website for LGBT people around the world

Sports and recreation
Out (baseball), a play which retires the batter or a base runner
Out (cricket), the loss of a wicket by a batsman; also known as "dismissal"
Out (poker), an unseen card which is expected to win a hand, if drawn
Out (route), a pattern run by a receiver in American football

Sexuality
Coming out, publicly revealing ones own LGBT status
Outing, publicly revealing someone elses LGBT status

Mathematics
Out(Fn), the outer automorphism group of a free group on n generators
Outer automorphism group, a quotient Out(G) of the automorphism group

Transport
Outwood railway station, West Yorkshire, National Rail station code

Other uses
Out, a procedure word in voice radio communication

See also
Outing (disambiguation)
Outside (disambiguation)
All pages with titles containing Out
All pages with titles beginning with Out