Deficits in social functioning are a defining, very burdening feature of schizophrenia precluding patients from participating in a satisfying life. Traditional drug and psychosocial therapy and available specific treatment strategies that directly target single key determinants of functional outcome like neurocognition, social cognition, and social behavioral skills have produced only moderate effects leaving an urgent need for further optimization. The present trial aims to more efficaciously improve functional outcome by integrating social behavioral and social cognitive treatment strategies. Six months of "Integrated Social Cognitive and Behavioral Skills Therapy (ISST)" will be compared with "Neurocognitive Remediation Therapy (NCRT)" as active control condition in a randomized multicenter clinical trial using a two group pre-post design with 2x90 patients in the remitted early phase of schizophrenia. Beyond "all-cause-discontinuation" as common primary outcome of all clinical trials of the ESPRIT-consortium, measures of functional outcome and subjective quality of life, patient experience as well as neurocognitive, social-cognitive and social behavioral measures will be assessed at baseline (V0), after completion of treatment (V6), and after 6 months follow-up (V12). ISST is expected to reduce the one-year discontinuation rate by 20% compared with NCRT, and to be superior in functional outcome measures by an effect size of at least d=0.42.