4. Sample size rationale The estimated sample sizes allow testing effects of medium size between individuals with schizophrenia and healthy controls with a power of 0.8, based on one-sided two-sample t-test power calculation with Cohen's d = 0.5, α = 0.05. They allow measuring medium correlations within groups with a power of 0.7, based on approximate correlation-power calculation with r = 0.3, α = 0.05.