between emergency caesarean sections (C-sections), excess bleeding, uterine rupture, and stillbirth (amongst other complications) and the subsequent development of PPP; however, several of the reviewed studies were contradictory and thus no consensus can confirm the relationship between problems related to pregnancy and PPP. Lifestyle and psychological factors, such as previous trauma or single parenthood, have likewise been inconclusive as factors contributing to PPP, though reports from several of the patients who suffered from PPP suggest a perception that social and pregnancy-related challenges were the cause of their episodes. Pathophysiology Currently, the pathophysiology of PPP is not well understood and remains an open field of ongoing research. The leading theories under investigation involve areas of genetics, hormones, immunology, and sleep disturbance processes. Genetics The majority of research devoted to genetic understanding of PPP has evaluated patients who have known bipolar disorder, therefore findings uncovering variation in serotonin transporter genes and signaling or changes at specific chromosomes (e.g., 16p13 or METTL13) are not necessarily precise to PPP generally. Hormones Despite significant hormone changes that occur around pregnancy and childbirth, there is little evidence supporting hormonal causes behind PPP. Changes in corticotropin-releasing hormone (CRH) and adrenocorticotropic hormone (ACTH), as well as rapid changes in estrogen and progesterone, are known effects associated with delivering a child, and they are present in both those affected and unaffected by PPP; therefore, the relationship between hormonal change and the onset of psychosis is not well-supported, though some researchers continue to explore potential differences in sensitivity to rapid hormone change as it relates to postpartum disorders such as postpartum depression. Estrogen has known impacts on various neurotransmitters (e.g., glutamate, GABA, serotonin and dopamine), including the increase of dopamine synthesis along with its receptors. The predominant theories surrounding psychosis include dysfunction in serotonin and/or dopamine systems, thus strong interest was placed in the association between estrogen changes and PPP onset; however, investigations of estrogen concentrations, dopamine receptor sensitivity, and trials of estrogen replacement following birth currently do not lend support for this theory. Immune System Alteration The theory between immune system changes and associated PPP onset has been largely spurred by higher than average occurrences of PPP in individuals also experiencing immunologic complications, such as anti-N-methyl-D-aspartate (NMDA) receptor encephalitis and autoimmune thyroid disorders, as well as the onset of PPP occurring at the same time the body is experiencing higher immune responses (a natural process associated with the period