The VAGUS measures the core dimensions of clinical insight into psychosis, including general illness awareness, symptom attribution, awareness of need for treatment, and awareness of negative consequences attributable to the illness. The VAGUS was designed to assess clinical insight in schizophrenia spectrum disorders, namely schizophrenia and schizoaffective disorder. The scale, however, can be used to assess clinical insight in any psychotic disorder, e.g. mood disorders with psychotic features, such as bipolar disorder or depression.
The VAGUS is the first insight into psychosis scale with both self-report and clinician-rated versions. It is easy to administer. The 10-item self-report (VAGUS-SR) and 5-item clinician-rated (VAGUS-CR) can be completed in less than 5 minutes. Both the VAGUS-SR and VAGUS-CR show good internal consistency, reliability and validity. Using a 10-point Likert scale for each item, the VAGUS has the capacity to detect small, temporally sensitive changes in insight, which is essential for intervention studies with neurostimulation or other rapidly acting interventions.