Table 1

Demographic and clinical characteristics

VariableEarly-onset OCD (n = 49)Late-onset OCD (n = 52)Healthy controls (n = 103)Statistical testp value
Male/female, n35/1434/1864/39χ22 = 1.270.53
Left-handed/right-handed, n3/465/477/96χ22 = 0.550.76
Drug-naïve/unmedicated, n17/3224/28χ21 = 1.370.24
Symptom dimensions, n (%)*
 Aggressive/checking17 (35)28 (54)χ21= 3.490.06
 Contamination/cleaning15 (31)19 (37)χ21 = 0.220.64
 Symmetry/ordering17 (35)10 (19)χ21 = 3.410.07
 Sexual/religious6 (12)5 (10)χ21 = 0.220.64
 Hoarding1 (2)0 (0)χ21 = 1.100.30
 Miscellaneous18 (37)15 (29)χ21 = 0.890.35
Age, yr, mean ± SD23.27 ± 5.1625 ± 4.7725.24 ± 6.86F2,201 = 1.890.15
IQ, mean ± SD110.94 ± 9.22110.18 ± 12.88113.13 ± 12.62F2,200 = 1.230.30
Total intracranial volume, L, mean ± SD1.55 ± 0.131.50 ± 0.131.49 ± 0.15F2,201 = 2.860.06
Age at onset, yr, mean ± SD13.18 ± 2.2521.35 ± 3.51t87 = −13.98< 0.001
Duration of illness, yr, mean ± SD9.98 ± 5.823.69 ± 3.24t74 = 6.65< 0.001
Y-BOCS score, mean ± SD
 Total27.47 ± 5.9526.04 ± 6.54t99 = 1.150.25
 Obsessions14.37 ± 3.2813.98 ± 2.65t99 = 0.650.52
 Compulsions13.10 ± 3.4212.06 ± 4.80t93 = 1.270.21
HAM-D score, mean ± SD11.10 ± 6.6611.67 ± 5.62t99 = −0.470.64
HAM-A score, mean ± SD10.82 ± 6.8910.62 ± 4.82t85 = 0.170.87
  • HAM-A = Hamilton Anxiety Rating Scale; HAM-D = Hamilton Depression Rating Scale; IQ = intelligence quotient; OCD = obsessive–compulsive disorder; SD = standard deviation; Y-BOCS = Yale–Brown Obsessive Compulsive Scale.

  • * As measured using the Y-BOCS symptom checklist.

  • We assessed IQ using the short form of the Wechsler Adult Intelligence Scale, which includes vocabulary, arithmetic, block design, and picture arrangement subtests.29