The role of imageability and frequency in language production and comprehension in first-episode and early-course psychosis

This study is an overview of language production and the comprehension of associations depending on the lexical-semantic imageability and frequency features in subjects with first-episode and early-course psychosis. Concepts with low values of lexical-semantic feature imageability, unlike those with high imageability, demand greater cognitive effort in the creation of their mental image and their activation in the semantic memory. This study included two tests, a forced-choice language comprehension test and an elicited association production test, which were constructed for the purpose of the study on the basis of an existing database of psycholinguistic lexical-semantic features (Erdeljac et al., 2018). Twelve subjects diagnosed with first-episode early-course psychosis were recruited, as well as 12 healthy subjects as a control group. It was confirmed that the target group, the subjects with first-episode and early-course psychosis, processes language differently with regards to the imageability feature in the production test. The patient group had longer reaction times on both imageability conditions in relation to the control group, but while the control group had shorter reaction times on highly imageable words, the patient group’s reaction times did not differ on account of the imageability condition. In the comprehension test, the patient group had overall longer reaction times independently of the imageability condition. Furthermore, in the comprehension test, both groups statistically more often chose associations that were of high and medium frequency, when compared to low frequency words, and the target group had longer reaction times on highand medium-frequency words than on low-frequency words. The results analysis was conducted according to current psycholinguistic theories and further validate the theory that subjects with schizophrenia have increased activation and decreased inhibition in the spreading of activation in the semantic memory during language processing.