O9.6. SIX MONTH LONGITUDINAL FEASIBILITY STUDY USING A SMARTPHONE APP (EXPRESS) TO ASSESS EARLY SIGNS AND BASIC SYMPTOMS AS PUTATIVE PREDICTORS OF PSYCHOSIS RELAPSE

Abstract

Background: Psychosis relapses are common, have profound adverse consequences for patients, and are costly to health services. 'Early signs' have been used to predict relapse, in the hope of prevention or mitigation, with moderate sensitivity and specificity. To improve predictive power, we investigated adding 'basic symptoms' to conventional early signs and using a smartphone app to facilitate prompt identification of these. Method(s): Individuals who had experienced a relapse of psychosis within the past year (n=22) took part in a screening interview. Those with at least one basic symptom emerging prior to a previous relapse (n=19; 86%) were eligible for the longitudinal feasibility study. Consenting participants (n=18) were asked to use a smartphone app ('ExPRESS') weekly for six months to report early signs, basic symptoms and psychotic symptoms. When app responses indicated an increase in psychotic symptoms above a pre-defined threshold, the researcher conducted the PANSS positive symptoms interview over the telephone to assess whether the symptom increase was indicative of relapse (in combination with a management change, evidenced by casenote review). On completion of, or dropout from, the app-use phase, participants were invited to give their views on the acceptability of the app and study procedures in a qualitative interview. Result(s): Participants completed 65% of app assessments and 58% of telephone interviews over the 6-month follow-up period. Completion of app assessments declined as the study progressed (OR=0.89 per week follow-up; p<0.001). Percentage app completion was significantly and inversely correlated with baseline depression (rho=-0.56, p=0.015) and fear of relapse (rho=-0.58, p=0.014). App items showed high concurrent validity with researcher-rated psychotic symptoms (rho range 0.80 to 0.87, p<0.001) and basic symptoms (ICC=0.76, p<0.001) over six months. There was excellent agreement between telephone call and face-to-face assessed psychotic symptoms (ICC range 0.94 to 0.96, p<0.001). The primary relapse definition, based on telephone assessment and casenotes, compared well with a casenote-only definition but had better specificity (kappa=0.76, p=0.003). Mixed-effects models (>200 observations) provided preliminary evidence of predictive validity: early signs and basic symptoms were associated with most app-assessed psychotic symptom variables the same week and three weeks later and adding basic symptoms to early signs improved model fit in most cases. Qualitative interviews indicated that both the app and study procedures were acceptable to patients with psychosis. Discussion(s): This study demonstrates that weekly app-based monitoring is feasible, valid and acceptable over a six-month period. It also provides a novel approach to operationally defining relapse by using a combination of telephone interviews and casenotes. We suggest that remote relapse assessment is more easily integrated into participants' everyday lives, decreasing both participant and researcher burden; this is likely to increase engagement and allow more frequent and long-term monitoring.