Psychopathology symptoms were measured by the Positive and Negative Syndrome Scale (PANSS) which is an extensively validated 30 item scale in which each Likert type item is rated from 1 to 7 with higher scores indicating more severe symptoms (Kay et al., 1987). We used the NIMH consensus model to construct our psychopathology symptom variables as a previous study done on CATIE data has shown that this model fit the data the best (Stefanovics et al., 2014). The NIMH consensus model uses 20 out of the 30 items in PANSS and constructs five symptom dimensions – positive, negative, disorganized, excited and depressed. Please see Table 1 for details on these variables.Table 1Variables analyzed.Table 1VariableDescriptionMeasures/testsPsycho-pathology symptomsPositiveSum of PANSS items P1, P3, P5 and G9PANSSNegativeSum of PANSS items N1, N2, N3, N4, N6, G7DisorganizedSum of PANSS items P2, N5 and G11ExcitedSum of PANSS items P4, P7, G8, G14DepressedSum of PANSS items G2, G3 AND G6Cognitive domainsNeurocognitionComposite score of standardized domain scores of:1.Working memoryComputerized test of visuo-spatial working memory2.Verbal memoryHopkins Verbal Learning Test3.VigilanceContinuous Performance Test4.Processing speed−Controlled oral word association test−Category Instance−Grooved peg boardWechsler
