Test-performance after cognitive training in persons at risk mental state of schizophrenia and patients with schizophrenia

This exploratory study aims to examine the differential effects of a computer-based cognitive training in 'prodromal' patients (mean age 27.20 years, S.D. 5.31 years) compared with patients with full-blown schizophrenia (mean age 30.13 years, S.D. 7.77 years). Ten patients at risk for schizophrenia and 16 patients suffering from schizophrenia underwent a computerized cognitive training program (Cogpack). Cognitive functioning before and after a total of 10 training sessions was assessed by different tests controlling for memory, attention, and logical thinking. Prodromal patients turned out to be able to significantly improve their long-term memory functions and their attention after cognitive training with the Cogpack software package whereas in the group of patients with schizophrenia no improvement occurred (e.g. continuous performance test, identical pairs-subtest 'shapes': improvement from 0.73 to 0.88 in persons at risk of schizophrenia vs. no improvement in patients with schizophrenia (0.55 to 0.53). Cognitive training using Cogpack is helpful for the improvement of cognitive functioning in persons at risk of schizophrenia. Thus, the application of cognitive training should be provided as early as possible in the prodromal phases of schizophrenia in order to use the full rehabilitative potential of the patients. These results should be confirmed by further investigations including larger sample sizes

Reduction of auditory event-related P300 amplitude in subjects with at-risk mental state for schizophrenia

Neurophysiological methods allow the examination of cognitive-cortical functioning in patients with schizophrenia in its prodromal states. As revealed by previous studies, event-related potential components such as auditory evoked P300 associated with cognitive processes, such as attention and orientation, are known to be reduced in amplitude in acute and chronic as well as in medicated and unmedicated patients. It is, however, unclear whether a P300 amplitude reduction occurs before the schizophrenic psychosis is fully manifested. We studied patients in the prodromal phase of the schizophrenic disorder (i.e. subjects with an at-risk mental state showing attenuated psychotic symptoms or brief limited intermittent symptoms) as well as first-episode patients and chronic patients with schizophrenia and compared these groups to healthy subjects. The event-related P300 was recorded during an auditory oddball paradigm. Groups differed significantly from each other in the P300 amplitude at Pz (F(3/149)=2.532, p=0.02). Post-hoc tests revealed significantly lower P300 amplitudes of non-medicated prodromal (p=.03), first-episode (p=.01) and chronic patients (p=.001) compared to the healthy controls. The study revealed that there are neurophysiological changes as the reduction in P300 amplitudes begins early in schizophrenia at the prodromal phase, i.e. before a manifestation of full-blown psychosis, and that these changes seem to have a progressive course from prodromal to chronic state of schizophrenia as assumed in this cross-sectional study

Ventral striatal activation during reward processing in subjects with ultra-high risk for schizophrenia

Background: Early dysfunction of the brain reward system in schizophrenia might be already recognized in the prodromal phase of this illness. We used functional magnetic resonance imaging to assess the blood oxygen level-dependent response in the ventral striatum (VS) of subjects with ultra-high risk for psychosis during the presentation of reward-indicating and loss-indicating stimuli. Methods: Thirteen prodromal patients (mean age: 25.5 ± 4.6 years) and 13 age-matched healthy volunteers participated in an incentive monetary delay task, in which visual cues predicted that a rapid response to a subsequent target stimulus will gain money, avoid losing money or have no consequence. Results: Compared with the neutral condition, anticipation of reward loss-avoidance elicited significant activation of the VS in both healthy subjects and subjects with ultra-high risk for psychosis, but there was only a statistical tendency for less activation during loss-avoidance anticipation in prodromal compared to healthy subjects. Discussion: This study provides a first weak hint, as revealed by functional magnetic resonance imaging, for impaired activation of a central area of the mesolimbic dopaminergic brain reward system, the VS, already in subjects with ultra-high risk for psychosis, which is in line with results of patients with full-blown schizophrenic psychosis. This pilot study has, however, strong limitations, and its results need to be replicated first before they can be used e.g. for early recognition of patients in the schizophrenic prodrome