Recurrent acute and transient psychotic disorder: A pilot study

• 65% of recurrences in acute and transient psychotic disorder (ATPD) occur in the first two years.
• Stress-related ATPD tends to be stress-related in subsequent episodes.
• A late age at onset and a relapse within two years are related to greater episode frequency.

Acute and transient psychotic disorder (ATPD) is associated with recurrent episodes of illness in 35–45% of cases. However, the course of such relapses and the factors associated with them are unclear. 20 patients with an ICD-10 diagnosis of ATPD (F23.x) who had experienced at least two episodes of illness, and who had been followed up for at least one year, were interviewed and their case records were reviewed. Information pertaining to relapses, their frequency, and the factors associated with them were collected and analyzed. The mean episode frequency was 0.7 episodes per year. Relapse within two years of the first episode (p = 0.001) and a later age at onset (p = 0.016) were significantly associated with a higher frequency of episodes. Relapse rates were 30% after a second episode and 50% after a third; mean inter-episode intervals decreased with the number of episodes, but not significantly. Patients with a stress-related onset of ATPD tended to have further stress-related relapses. Diagnostic subtypes of ATPD tended to remain stable over time. Though acute and transient psychotic disorder is a recurrent condition, recurrences do not increase significantly over time, and there is no clear evidence for a shortening of the inter-episode period. A later onset of ATPD may be associated with greater illness severity. These results are preliminary and require replication in larger prospective samples.