Table 2.

Details of variables and tests

Domain	Explanatory variables of interesta (predictors)	Analysis performed	N (subjects with available data)
Demographics	Age, sex, handedness	Linear regression	482
Impulsive behavior	Alcohol consumption, current smoking, Body Mass Index (BMI)	Linear regression	477
Self-paced tasks	Verbal fluency, semantic fluency	Linear regression	486
Mood	CES-D	Partial correlation	485
Motor performance and sleep	CANTAB RTI (MT, RT), Pegboard (left, right, both, assembly), PSQI_11c	Linear regression	270

Legend: CES-D = Centre for Epidemiological Studies Depression Scale; CANTAB RTI = Cambridge Neuropsychological Test Automated Battery Reaction Time (CANTAB eclipse 5.0; Cambridge Cognition Ltd. http://www.camcog.com) touchscreen version (RT = mean simple reaction time for correct responses, MT = movement time for correct responses); Pegboard = Purdue pegboard task; PSQI = Pittsburgh Sleep Quality Index

^aVolume of BG structures was included as covariate in all (ROI and voxel-wise) analyses