Diagnostic stability of first onset severe mental illness during postpartum period- findings from a mother-baby unit.

PURPOSE: We examined the diagnostic stability of first-onset severe mental illness (SMI) during the postpartum period and the vulnerable period to develop first-onset SMI during the first six months following delivery.

METHODS

We reviewed the records of women admitted to a mother-baby unit for first-onset SMI during the first six months following delivery. Diagnostic stability was estimated through prospective and retrospective consistency measures for women with a two-year follow-up after the first-onset SMI episode.

RESULTS

A total of 120 women with first-onset SMI were identified, with 77.5 % experiencing symptom onset within the first 12 weeks following delivery. Forty-seven out of the 120 women met the follow-up criteria of two years. Relapse/ recurrence of severe mental illness was observed in 27/47 (57.4 %) patients. Among the 27 women with relapse/ recurrence, 14 (51.8 %) had a change in diagnosis. The highest rate of change in diagnosis (43.7 %) was noted among women with acute transient psychotic disorder (ATPD); among them, 25 % converted to bipolar affective disorder. Prospective consistency was highest for severe depressive episode and unspecified non-organic psychosis, while ATPD demonstrated the highest retrospective consistency.

CONCLUSION

Women with first-onset ATPD have a higher chance of recurrence and conversion to bipolar disorder. Women diagnosed with severe depressive episode, or unspecified non-organic psychosis for the first-onset episode during the postpartum period tend to maintain the same diagnosis over time. It is unlikely for other SMI to convert to psychotic disorder during follow-up. The initial 12 weeks post-delivery is a vulnerable period for first-onset SMI.