Clinical Data Acquisition

Clinical data were acquired at the Psychiatric Clinic at the Haukeland University Hospital in Bergen, Norway. The study was approved by the Regional Committee for Medical Research Ethics in Western Norway (REK Vest) (REK # 2010/3387) and conducted according to the Declaration of Helsinki. Severity of AVH was assessed with the P3 item of the Positive and Negative Syndrome Scale [PANSS, (24)]. All PANSS raters were trained and certified, and satisfactory inter-rater reliability was documented. Although the PANSS P3 item does not explicitly differentiate between different sensory modalities of hallucinations, auditory hallucinations are by far the most common type of hallucination in psychotic patients (25), typically in the form of hearing voices (26). Furthermore, AVH are also the main focus during the PANSS P3 interview (27). Therefore, the PANSS P3 is a good indicator of AVH.