Language impairment in schizophrenia, its clinical and cognitive correlate

Objectives Majority of the schizophrenia patients suffer from speech disorder. Patients with schizophrenia may continue to demonstrate speech disorder even though other psychotic symptoms improve. Hence, language disorder is one of the main reasons of chronic social impairment. This study designed in a case-controlled fashion that aims to define the characteristics of language disorders in schizophrenia and to identify the underlying socio-demographic, clinical and cognitive factors. Method This study includes 65 subjects aged between 19 and 50 with similar socio-demographic characteristics among which 34 of them with schizophrenia and 31 healthy volunteers. All the subjects in both groups underwent several tests to identify the language impairment. These are: Thought and language and Language Index (TLI) addition to the scales of coherence, cohesion and story elements. The data is collected by using 8 Thematic Apperception Test (TAT) cards to produce short stories related to these cards. In order to assess general cognitive function, IQ test and neuropsychological tests also carried out. Results This study demonstrated significant impoverishment and disorganization of speech functions among schizophrenia patients compared to healthy controls. The level of impoverishment was found to be associated to the clinical features of the patient with positive and negative symptoms of the disorder. Positive symptoms such as bizarre behavior and formal thought disorder are found to be directly proportional to the level of disorganization among stories. By contrast, negative symptoms such as flattening of the affect and alogia are found to be directly proportional to the impoverishment of speech functions. The performance on neuropsychological tests in the control group was found to be negatively associated with impairment language. By contrast, no relationships were found in patients with schizophrenia other than phonological verbal fluency. The relationship between cognitive status and language skills considered to be weakened due to the pathological processes in schizophrenia. On the other hand, in healthy controls, verbal IQ was found to negatively correlated to both impoverishment and disorganization of speech functions whereas in schizophrenia patients verbal IQ was found only related to the disorganization of speech functions. Conclusions Language disorder seen in patients with schizophrenia (impoverishment, disorganization) are found to be dependent to the clinical symptoms (positive and negative), but independent to the general cognitive status of the associated schizophrenia patients