Introduction: Pre-psychotic and early psychotic characteristics are investigated in the high-risk (HR) populations for psychosis.
There are two different approaches based either on hereditary factors (genetic high risk, G-HR) or on the clinically manifested symptoms
(clinical high risk, C-HR). Common features are an increased risk for development of psychosis and similar cognitive as well as
structural and functional brain abnormalities.
Methods: We reviewed the existing literature on longitudinal structural, and on functional imaging studies, which included G-HR and/or
C-HR individuals for psychosis, healthy controls (HC) and/or first episode of psychosis (FEP) or schizophrenia patients (SCZ).
Results: With respect to structural brain abnormalities, vulnerability to psychosis was associated with deficits in frontal, temporal, and
cingulate regions in HR, with additional insular and caudate deficits in C-HR population. Furthermore, C-HR had progressive prefrontal
deficits related to the transition to psychosis.
With respect to functional brain abnormalities, vulnerability to psychosis was associated with prefrontal, cingulate and middle temporal
abnormalities in HR, with additional parietal, superior temporal, and insular abnormalities in C-HR population. Transition-to-psychosis
related differences emphasized prefrontal, hippocampal and striatal components, more often detectable in C-HR population.
Multimodal studies directly associated psychotic symptoms displayed in altered prefrontal and hippocampal activations with striatal dopamine
and thalamic glutamate functions.
Conclusion: There is an evidence for similar structural and functional brain abnormalities within the whole HR population, with more
pronounced deficits in the C-HR population. The most consistent evidence for abnormality in the prefrontal cortex reported in structural,
functional and multimodal studies of HR population may underlie the complexity of higher cognitive functions that are impaired during
HR mental state for psychosis.