Background: Auditory verbal hallucinations (AVH), or voice-hearing, can be a prominent symptom during fluctuating mood states in bipolar disorder (BD).
Aims: The current study aimed to: (i) compare AVH-related distress in BD relative to schizophrenia (SCZ), (ii) examine correlations between phenomenology and voice beliefs across each group, and (iii) explore how voice beliefs may uniquely contribute to distress in BD and SCZ.
Method: Participants were recruited from two international sites in Australia (BD=31; SCZ=50) and the UK (BD=17). Basic demographic-clinical information was collected, and mood symptoms were assessed. To document AVH characteristics, a 4-factor model of the Psychotic Symptoms Rating Scale and the Beliefs about Voices Questionnaire-Revised were used. Statistical analyses consisted of group-wise comparisons, Pearson's correlations and multiple hierarchical regressions.
Results: It was found that AVH-related distress was not significantly higher in BD than SCZ, but those with BD made significantly more internal attributions for their voices. In the BD group, AVH-related distress was significantly positively correlated with malevolence, omnipotence and resistance, However, only resistance, alongside mania and depressive symptoms, significantly contributed to AVH-related distress in BD.
Discussion: Our findings have several clinical implications, including identification of voice resistance as a potential therapeutic target to prioritise in BD. Factoring in the influence of mood symptoms on AVH-related distress as well as adopting more acceptance-oriented therapies may also be of benefit.
Keywords: Auditory verbal hallucinations; Bipolar disorder; Hallucinations; Voice-hearing; Voices.