Similarities and Differences in Associations Between Duration of Untreated Psychosis (DUP) and Demographic, Premorbid, and Symptom Severity Measures in Two Samples of First-Episode Psychosis Patients from Mexico and the United States.

Early-psychosis researchers have documented that duration of untreated psychosis (DUP) is an important predictor of outcomes in first-episode psychosis. Very few cross-national studies have been conducted, and none have been carried out involving patients from both Mexico and the U.S. We collaborated to answer three questions: (1) Are DUP estimates similar in two very different settings and samples? (2) Are demographic variables, premorbid adjustment, and symptom severity similarly related to DUP in the two different settings? (3) Does the same set of variables account for a similar proportion of variance in DUP in the two settings? Data on sociodemographic characteristics, premorbid adjustment, symptom severity, and DUP were available for 145 Mexican and 247 U.S. first-episode psychosis patients. DUP was compared, and bivariate analyses and multiple linear regressions were carried out in each sample. DUP estimates were similar (medians of 35 weeks in Mexico and 38 weeks in the U.S.). In the Mexican sample, DUP was associated with gender, employment status, premorbid social adjustment, and positive symptom severity (explaining 18% of variance). In the U.S. sample, DUP was associated with age, employment status, premorbid social adjustment, and positive symptom severity (but in the opposite direction of that observed in the Mexican sample), accounting for 25% of variance. Additional cross-national collaborations examining key facets of early-course psychotic disorders, including DUP, will clarify the extent of generalizability of findings, strengthen partnerships for more internationally relevant studies, and support the global movement to help young people struggling with first-episode psychosis and their families.