Editorial. Schizophrenia : human and animal studies

Schizophrenia is a complex disorder with relatively stable prevalence rates estimated at about 0.5-1% (Saha et al., 2005). Schizophrenia is characterized by the occurrence of various psychopathological symptoms that have been described as positive symptoms (delusions and hallucinations), negative symptoms (apathy, lack of motivation, flat affect, poverty of speech, and social withdrawal), disorganized symptoms (disorganized speech and behavior), and cognitive impairment (Moustafa et al., 2016). Traditionally, cognitive impairment was thought to be evident only in elderly deteriorated patients with schizophrenia; however, over the past 25 years, a body of evidence challenged this view and showed that cognitive dysfunction is a core feature of schizophrenia (O'Carroll, 2000; Weickert et al., 2000; Bora et al., 2010). Cognitive deficits can be moderate to severe across several domains, including attention, working memory, verbal learning and memory, and executive functions (Weickert et al., 2000; Bowie and Harvey, 2006). These deficits pre-date the onset of psychosis and further decline in cognitive functioning is observed in the course of illness in most patients (Trotta ct al., 2015). Numerous rehabilitation programs have been developed in order to alleviate the burden associated with cognitive impairment in schizophrenia since cognitive deficits respond poorly to antipsychotic treatment (Tao et al., 2015). Below we describe articles in this research topic (mostly focusing on cognitive studies in schizophrenia), dividing them into human vs. animal studies.