Table 1

Sample characteristics

CharacteristicControl (n = 34)ADHD (n = 34)Test statistic with effect size (group comparison)
Age, yr, mean ± SD27.62 ± 7.4330.29 ± 9.47t66 = 1.30, NS; d = 0.31
IQ, mean ± SD*118.6 ± 15.7115.7 ± 14.6t65 = −0.79, NS; d = −0.19
Years of education, mean ± SD12.88 ± 1.2112.75 ± 0.76t54 = −0.51, NS; d = −0.13
ASRS hyperactivity, mean ± SD8.7 ± 4.320.5 ± 4.9t66 = 10.60, p < 0.001; d = 2.56
ASRS inattention, mean ± SD§10.4 ± 4.324.6 ± 4.6t66 = 13.15, p < 0.001; d = 3.19
I7 impulsivity, mean ± SD4.9 ± 2.211.9 ± 2.9t66 = 10.66, p < 0.001; d = 2.72
Sex, female/male, no.18/1613/21χ2 = 1.48, NS; V = 0.15
Handedness, right/left, no.30/428/6χ2 = 0.47, NS; V = 0.08
Smoker/nonsmoker, no.10/2411/22**χ2 = 0.12, NS; V = 0.04
  • ADHD = attention-deficit/hyperactivity disorder; ASRS = Adult ADHD Self-Report Scale; I7 = Eysenck’s Impulsiveness Questionnaire; IQ = intelligence quotient; NS = not significant; SD = standard deviation.

  • * IQ was assessed based on the Mehrfachwahl-Wortschatz Intelligenztest (information missing for 1 participant).

  • Information missing for 3 participants.

  • Hyperactivity subscale of the Adult ADHD Self-Report Scale.

  • § Inattention subscale of the Adult ADHD Self-Report Scale.

  • Impulsivity subscale of Eysenck’s Impulsiveness Questionnaire I7 (data missing for 4 people with ADHD and 2 controls).

  • ** Information missing for 1 participant.