Characterising Perceptual Rivalry in Psychiatric Disorders

CHARACTERISING PERCEPTUAL RIVALRY IN PSYCHIATRIC DISORDERS

Background

Bipolar disorder is a serious psychiatric condition that is characterised by alternations between periods of extremely depressed mood and extremely elevated mood. These mood changes are often associated with a variety of behavioural changes, including sleep disturbance, impulsiveness, and suicidal ideation. Bipolar disorder is also associated with psychotic symptoms, such as hallucinations and delusions. These symptoms and behavioural changes cause severe difficulties in day-to-day functioning for individuals with the illness. It has been estimated that 1.8% of Australians have a diagnosis of bipolar disorder (Australian Bureau of Statistics, 2007), which represents a substantial burden of illness for the community.
The hereditary nature of bipolar disorder indicates a significant role of genetics, which can influence the type of symptoms and biological abnormalities that are observed. Identification of a robust biological marker or ‘endophenotype’ for bipolar disorder remains elusive. Key criteria need to be satisfied for a marker to qualify as an endophenotype, such as high sensitivity (i.e. high association with the condition), high heritability, and high reliability. A candidate biomarker for bipolar disorder that appears to satisfy these criteria is binocular rivalry rate – a visual perception measure. In the present study, the trait’s discriminative capacity will be further assessed in a sample of bipolar disorder patients and patients with other psychiatric disorders.

Aims

The study aims to examine binocular rivalry (the rate of alternation between two dissimilar images one to each eye) in a discriminative capacity to differentiate subjects with Bipolar I, Bipolar II, Major Depressive Disorder and Schizophrenia. The project design will include one hundred and sixty suitable volunteers, (18-75 years) who will be asked to complete a 20-minute binocular rivalry rate (BRR) testing session. Clinical subjects such as those with Bipolar I, Bipolar II, Major Depressive Disorder and Schizophrenia will also be asked to complete a diagnostic interview and objective mood and psychosis state ratings.