To achieve a normal distribution, ZNF804A expression values were log transformed, and normality of the transformed data was verified by the Anderson-Darling empirical distribution function test49,50, a powerful statistic to detect departure from normality even in a relatively small (N≤100) sample. Samples (N=7, 3 SCH and 4 CON) with values greater than ±2SD from the group mean were omitted from further analyses, reducing the totals to 32 SCH and 30 CON. Mean expression levels in SCH and CON groups were compared using Welch’s corrected unpaired t-test. The potential confounding effects of diagnosis, age, gender, pH, post-mortem interval, refrigerator interval, smoking and drug abuse in the analysis of ZNF804A expression were assessed by analysis of variance (ANOVA).
