Predictors of short-term course in Mexican first-episode psychosis patients

Background and objectives: The identification of prognostic factors in patients with schizophrenia and related psychotic disorders should enhance our understanding of the aetiology of these disorders and improve their treatment. The first years following an initial episode of psychosis are a «critical period» for biological and psychosocial influences that affect future outcome. Both, short-term outcome and baseline predictors, have been defined by different measures, making the comparison among studies difficult. Studies of the predictive value of baseline demographic and clinical characteristics in the Mexican population are still limited. Hence, the present study aims to: 1. replicate the prognostic value of selected patient characteristics previously related to the short-term course of psychosis in Mexican first-episode psychosis patients, and 2. retrospectively assess their prognostic value in the prediction of diagnosis, presence of psychotic residual symptoms, and number of psychotic episodes at least three-years later. Methods: Information on baseline predictor variables (sociodemographic, premorbid phase, context of the first episode, dimensions of psychopathology) and clinical outcome (diagnosis, residual symptomatology, psychotic episodes) was obtained from the clinical records of 51 patients with a short-term course of psychosis and whose available follow-up period was at least three years long (mean=5.8, SD=2.1). Results: Poor premorbid adjustment and hospitalization at first psychotic episode were significant predictors of a schizophrenia diagnosis. Lower educational level and an insidious type of onset significantly predicted the presence of residual symptoms. Hospitalization at first psychotic episode and higher scores on the psychotic dimension at onset significantly predicted subsequent psychotic episodes. Discussion: Low educational level increased the risk of residual symptoms, possibly because it hinders treatment continuity. Poor premorbid adjustment was related to a schizophrenia diagnosis at the follow-up assessment, supporting previous findings of their high ratings for premorbid impairment, including social withdrawal and dysfunctional peer relationship. Insidious onset was predictive of persistent residual symptoms; an association possibly mediated by the duration of untreated psychosis (DUP). Being hospitalized at first episode was a significant prognostic factor for schizophrenia diagnosis and multiple psychotic episodes; the severity and nature of symptoms at first episode that require hospitalization might account for these associations. Replicating previous findings, multiple-episode patients scored significantly higher than the single-episode patients on the psychoticism dimension. Most baseline factors did not predict diagnosis. This seems congruent with a dimensional view of psychosis suggesting that even though schizophrenic and non-schizophrenic psychoses are classified as separate families of disorders, they exist along a continuum of psychosis that crosses diagnostic boundaries, sharing aetiological and risk factors. Currently, both the amelioration of severe psychotic symptoms and the improvement of psychosocial functioning and quality of life are feasible aims. Symptom exacerbation and hospitalizations might cause cumulative deterioration and impair the patient's social reintegration. Thus, relapse prevention is an important objective in treatment. The identification of reliable predictors of illness course has significant implications for treatment and service planning. Conclusions: The predictive value of several factors was replicated in this sample of patients with psychotic illnesses, although predictors seem to relate differently to the three short-term course measures. Comprehensively mapping the development and outcome of the first episode of psychosis requires the use of standardized measurement tools and the longitudinal assessment of multiple outcome measures.