Symptom dimensions refer to groups of psychopathological symptoms that commonly co-occur within psychosis individuals, with evidence indicating that these dimensions are associated with distinct pathophysiological markers. It is suggested that psychopathology of psychosis may be best conceptualized as an extreme value on a continuum rather than a discrete symptom that may either be present or absent. There is strong evidence for a continuous distribution of psychosis-like symptoms in the general population, ranging from self-reported attenuated or infrequent psychotic experiences to full-blown psychotic symptoms.
According to Strik and Dierks, psychotic symptoms represent disturbances in higher-order brain functions such as symbolic thinking, language, planning, empathy or complex emotional reactions. Based on the assumption that the psychopathology of psychosis is related to a functional imbalance of higher-order brain systems, it is suggested that psychotic symptoms can be grouped according to their respective underlying dysfunction of three distinct, anatomically and functionally segregated brain circuitries.
In detail, these are the brain’s language, limbic and motor systems with their well described cortico-basal ganglia and cortico-cortical circuitries. These symptom domains are of high relevance given their presumed role in the communication breakdown during psychotic episodes, and have been related to aberrant structural and functional findings in the respective brain systems.
In order to assess clinical symptoms of psychosis and categorize specific subgroups with behavioral alterations in the three dimensions of language, affectivity, and motor behavior, the Bern Psychopathology Scale (BPS) was developed.