Samylkin, D.V.

Background. The consideration of event occurrence probability is a foundational element in the formation of expectations and predictions, thereby playing a pivotal role in the regulation of actions and behaviour.

Objective. The aim is to identify abnormalities in the processing of probabilistically organized stimuli and their psychophysiological markers in individuals with personality disorders.

Study Participants. The study engaged 42 participants, 21 men diagnosed with a personality disorder (Mage = 30.95, SD = 7.4) and 21 men serving as a control group (Mage = 32.26, SD = 7.06).

Methods. Participants completed the Central Cue Posner Paradigm with varying probabilities (50% and 80%) of coincidence between the target and the cue stimuli. Event-related potentials were recorded during the experiment.

Results. The differences between the groups were observed in the variations in their response patterns, which manifested as fronto-central activation in the 240–320 ms span after the target stimulus. In the control group, the amplitude in response to the invalid stimulus was higher only under the condition of an 80% probability of stimulus matching; under the condition of a 50% probability, no differences in amplitude between valid and invalid stimuli were observed. In the personality disorders group, the response to invalid stimuli exhibited a higher amplitude, irrespective of the probability of the stimuli.

Conclusions. Individuals diagnosed with personality disorders are characterized by impaired processing of probabilistically organized stimuli. This impairment manifests as a reduced use of information on the probability of an event occurring and may reflect a diminished influence of the context on information processing and increased reactivity to deviations from expectations.