Longitudinal data have been collected since 1991 in twins/their family members registered in the NTR. In 1993 and 1997, depression was measured with the BDI (Beck et al. 1974). Anxious depression (comparable to psychological distress) was measured with the (young) Adult Self Report (Achenbach and Rescorla 2003) in 1991, 1995, 1997, 2000, 2002 and 2009. BDI data comprised the 1997 dataset complemented with 1993 data, and the psychological distress dataset used the 2009 dataset complemented with data from the other time-points. The number of unrelated individuals (>18 years) with genotype and phenotype data was 2 685 (psychological distress) and 1 383 (depression). Mean age was 45.1 (SD 14.9) and 37.5 years (SD 12.3). Genome-wide genotyping was performed in a selection of subjects as part of six projects, including around 40% of the sample who participated in one of two Major Depressive Disorder GWAS studies (Sullivan et al. 2009; Wray et al. 2010). Affymetrix 6.0, Affymetrix Perlegen 5.0, Illumina 370, Illumina 660 and Illumina Omni Express 1M platforms were used. Following exclusions based on standard QC (see Psychiatric Genetics Network 2009),
