Background Cognitive deficits are core symptoms of schizophrenia that occur from the early stages of the disorder. There is reliable evidence that cognitive deficits are associated with outcomes in schizophrenia; thus, early treatment could be particularly important. Studies with different neuromodulation techniques involving subjects with schizophrenia suggest that application of transcranial direct current stimulation (tDCS) with inhibitory stimulation over the left temporo-parietal cortex and excitatory stimulation over the left dorsolateral prefrontal cortex could ameliorate positive, negative, and cognitive symptoms. The aim of the present study protocol is to evaluate the efficacy of tDCS in the treatment of cognitive symptomatology in the early stages of psychosis. Methods/design Seventy patients in the early stages of psychosis will be randomly allocated to receive 20 min of active 2-mA tDCS or sham stimulation once a day for 10 consecutive weekdays. The anode will be placed over the left dorsolateral prefrontal cortex and the cathode over the left temporo-parietal cortex. Neuropsychological and psychiatric assessments will be performed at baseline and at 1 and 3 months following the end of the intervention (sustained effect). Discussion The development and utilization of potentially effective neuroenhancement tools such as the non-invasive brain stimulation technique tDCS for the treatment and rehabilitation of cognitive impairment in the early stages of schizophrenia may contribute to improving outcomes of the disorder and eventually provide a further understanding of the nature of the complex and dynamic neural processes underlying those abnormalities. Trial registration ClinicalTrials.gov, NCT03071484 . Registered on 7 March 2017. Electronic supplementary material The online version of this article (10.1186/s13063-019-3288-5) contains supplementary material, which is available to authorized users.

BackgroundAlthough cognitive deficits have consistently been characterized as core features of schizophrenia, they have not been incorporated into definitions of remission. Furthermore, just a few studies have examined the relationship between cognitive deficits and symptomatic remission. The main aim of the present study is to evaluate the executive functioning of nonremitted schizophrenia patients.Methods72 remitted and 42 nonremitted schizophrenia patients, and 119 healthy controls were examined. Subjects were tested with a comprehensive battery of cognitive tests, including a measure to assess the general components of executive functioning and individual tasks to tap the three specific executive dimensions assessed in the present study, namely updating, shifting and inhibition.ResultsSchizophrenia subjects performed poorly on general executive functioning and shifting tasks in comparison to healthy controls. Remitted subjects performed better than nonremitted on inhibition and updating tasks. Whereas being a male and showing decreases in updating increase the chances of being in the nonremitted schizophrenia subjects group, increases in shifting and updating enhance the odds of being in the healthy control group.ConclusionThe present findings suggest that executive function deficits are present in chronic schizophrenic patients. In addition, specific executive processes might be associated to symptom remission. Future studies examining prospectively first-episode, drug naive patients diagnosed with schizophrenia may be especially elucidative.

Introduction: The accumulation of robust evidence culminated in the establishment of the cognitive deficits as a core symptom of Schizophrenia (SCZ). To date, there has been reliable evidence that cognitive deficits are associated with poor symptomatic outcomes in SCZ. Nevertheless, they have not been incorporated in definitions of remission and a systematic understanding of how cognition contributes to remission is still lacking. Although the standardized remission in SCZ criteria proposed in 2005 has encouraged studies to understand the role of cognitive function in symptomatic remission from SCZ, most investigations were cross-sectional and have studied samples of chronically ill patients. The purpose of the present study was to bring together the efforts of recent follow-up studies in early in earlier stages of the disease to fill the gap in the literature on understanding how cognitive impairment is related to remission.

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