Theory of Mind (ToM) deficit is investigated by psychological and neurobiological methods using a range of social cognitive tests, including the verbal test Hinting Task. However, it remains unclear whether there is a connection between ToM results and the physiological characteristics in norm and in pathology.

We performed the comparison of Hinting Task performance in patients with schizophrenia and healthy subjects; analysis of correlations between Hinting Task performance with physiological parameters; discriminant analysis in order to classify subject groups according to predictors, including psychological and physiological parameters.

We measured Hinting Task, spectral power of the EEG mu-rhythm (SP) and heart rate (HR) at rest and during a motion imagery task in 114 right-handed subjects, 1st episode patients with schizophrenia (SCH1) n = 29, chronically ill patients with schizophrenia, duration of illness more than 5 years, (SCH2) n = 23, and healthy subjects (НС) n = 62.

Hinting Task rate: HC > SCH2 (P < 0.01), HC ≥ SCH1 (P = 0.07), SCH1 = SCH2 (P = 0.3). Only SCH1 Hinting Task score was associated with a complex of physiological parameters in the resting state [Multiple R = 0.78, F (3.25) = 13.31, P < 0.0001]. Discriminant function analysis of HC and the combined SCH group [F (7.106) = 7.078, P < 0.0000]. The samples were classified at 89% and 71%, respectively, including HR (P < 0.000001), SP in the resting state in C4 (P < 0.001), C3 (P < 0.01), SP changes in C3 (P < 0.05) and Hinting Task (P = 0.2).

Hinting Task Hinting Task is a part of classification model of norm and schizophrenia. Patients with first episode and chronically ill patients with schizophrenia do not differ in the studied parameters.

The authors have not supplied their declaration of competing interest.