“…Existing early signs studies have typically used pen and paper questionnaires (Birchwood et al, 1989; Gaebel et al, 1993; Gaebel and Riesbeck, 2007, Gaebel and Riesbeck, 2014; Gleeson et al, 2005; Gumley et al, 2015; Hirsch and Jolley, 1989; Jørgensen, 1998; Malla and Norman, 1994; Marder et al, 1991; Marder et al, 1994; Subotnik and Neuchterlein, 1988; Tait et al, 2002; Tarrier et al, 1991) or text message systems (Spaniel et al, 2018; Spaniel et al, 2007; Spaniel et al, 2008) to examine the predictive value of conventional early signs of relapse. Compared to these methods, smartphone apps have a number of advantages: apps can be accessed at the individual's convenience (Ben-Zeev et al, 2013), decreasing participant burden and increasing ecological validity (Bucci et al, 2018); apps can automatically supply surveys and securely upload responses; finally, apps are more acceptable to individuals with psychosis than text message systems (Ainsworth et al, 2013).…”