Abstracts From the ISTS Satellite Meeting June 20, 2016, Brisbane

Abstract

Background: Binocular rivalry is a visual phenomenon in which simultaneous presentation of different stimuli, one to each eye, results in perceptual alternations or rivalry between the two images. Slow binocular rivalry rate (BRR) has been proposed as a potential endophenotype for the heritable psychiatric condition, bipolar I disorder (BD), because BRR is slower in BD than controls and is under substantial genetic influence (h2 = 0.52) (Ngo et al., Acta Neuropsychiatr, Vol. 23, 2011, pp. 37-42). The BRR trait also shows high sensitivity (~80%) and test-retest reliability (r = 0.70), but its relation to medication and state requires clarification, as does its specificity given recent reports of anomalous BRR in depression, anxiety disorders, and attention deficit hyperactivity disorder (ADHD). Aim(s): To examine in a large twin sample, the relationship between subjects' BRR and their psychiatric profile measures. Method(s): BRR was recorded and analyzed as per Miller et al. (PNAS, Vol. 107, 2010, pp. 2664-8) in 14-yearold twins (N = 1,143) participating in the Brisbane Longitudinal Twin Study (Wright & Martin, Aust J Psychol, Vol. 56, 2004, pp. 65-78). In subsamples with BRR, there were also the following data: (1) the SPHERE (Somatic and Psychological HEalth REport), a 34-item self-rated screening tool for anxiety-depression and chronic fatigue (N = 954; aged 14-14.6); (2) the SWAN (Strengths and Weaknesses of ADHD symptoms and Normal behavior) (N = 867), a DSM-V criteria-based 18-item rating scale for inattention, hyperactivity, and impulsivity symptoms completed by mothers of the twins; and (3) diagnoses of lifetime major depressive disorder (MDD; N = 439, 14% cases) and social anxiety disorder (SAD; N = 439, 17% cases) based on the Composite International Diagnostic Interview (aged 18-29, mean=23). Result(s): No association was found between subjects' BRR and their (1) anxiety-depression ratings (r = -0.07, p = .11; RG = -0.20, p = .11), (2) ADHD symptoms (r = -0.07, p = .09; RG = -0.18, p = .10), (3) MDD diagnosis (ORMDD = 1.20; p = .84), and (4) SAD diagnosis (ORSAD = 0.23; p = .09). Conclusion(s): The findings lend support to the BRR trait as a potential endophenotype for BD by suggesting high specificity to BD and no relationship to anxiety- depression, however further work is required on these endophenotype issues with much larger datasets. We will also present preliminary results on the genetic correlation between BRR and psychiatric disorders (based on LD score regression analyses with Psychiatric Genomics Consortium datasets), and plans for large-scale studies of the trait using an online binocular rivalry testing platform.