Table 2.
Predictors of change in contamination-related obsessive-compulsive symptoms (outcome: change in OCI − R washing subscale from t1 to t3), n = 852.
| B [CI95%] | β | p | |
|---|---|---|---|
| Step 1 | Model A1 | ||
| Constant | 1.531 [−0.721, 2.341] | <0.001 | |
| Age | − 0.014 [−0.027, −0.002] | −0.081 | 0.022 |
| Gendera | −0.112[−0.434, 0.209] | −0.024 | 0.493 |
| A-levels | −0.027[−0.348, 0.295] | −0.006 | 0.870 |
| Step 2 | Model A2 | ||
| Constant | −0.003 [−0.688, 0.682] | 0.993 | |
| Age | −0.009 [−0.019, 0.002] | −0.048 | 0.096 |
| Gendera | −0.070 [−0.335, 0.196] | −0.015 | 0.606 |
| A-levelsb | −0.069[−0.334, 0.196] | −0.015 | 0.611 |
| OCI − R washing subscale (t1) | 0.515 [0.464, 0.565] | 0.565 | <0.001 |
| χ2(1) = 402.51, p < 0.001 | |||
| Step 3 | Model A3 | ||
| Constant | −0.168 [−0.864, 0.528] | 0.636 | |
| Age | −0.008 [−0.019, 0.002] | −0.047 | 0.104 |
| Gendera | −0.066 [−0.331, 0.198] | −0.014 | 0.622 |
| A-levelsb | −0.044 [−0.310, 0.221] | −0.009 | 0.742 |
| OCI-R washing subscale (t1) | 0.516 [0.465, 0.566] | 0.566 | <0.001 |
| Change in duration of handwashing (t1 − t2) | 0.157 [0.031, 0.283] | 0.069 | 0.015 |
| χ2(1) = 5.36, p = 0.021 | |||
| Step 4 | Model A4 | ||
| Constant | −0.177 [−0.877, 0.522] | 0.619 | |
| Age | −0.008 [−0.019, 0.002] | −0.047 | 0.105 |
| Gendera | −0.065 [−0.330, 0.200] | −0.014 | 0.630 |
| A-levelsb | −0.045 [−0.310, 0.220] | −0.010 | 0.739 |
| OCI-R washing subscale (t1) | 0.516 [0.466, 0.567] | 0.566 | < 0.001 |
| Change in duration of handwashing (t1 − t2) | 0.155 [0.028, 0.282] | 0.068 | 0.017 |
| Change in frequency of handwashing (t1 − t2) | 0.012 [−0.080, 0.103] | 0.007 | 0.801 |
| χ2(1) = 0.04, p = 0.842 | |||
| Step 5 | Model A5 | ||
| Constant | −0.187 [−0.884, 0.510] | 0.598 | |
| Age | −0.008 [−0.018, 0.002] | −0.046 | 0.109 |
| Gendera | −0.069 [−0.333, 0.195] | −0.015 | 0.609 |
| A-levelsb | −0.023 [−0.288, 0.241] | −0.005 | 0.863 |
| OCI-R washing subscale (t1) | 0.514 [0.463, 0.564] | 0.564 | < 0.001 |
| Change in duration of handwashing (t1 − t2) | 0.147 [−0.021, 0.274] | 0.065 | 0.023 |
| Change in frequency of handwashing (t1 − t2) | 0.003 [−0.088, 0.094] | 0.002 | 0.950 |
| Change in negative reinforcement after handwashing (t1 − t2) | 0.198 [−0.060, 0.335] | 0.080 | 0.005 |
| χ2(1) = 8.03, p = 0.005 | |||
R2 = 0.008, F = 2.216 (p = 0.085) for step 1; ∆R2 = 0.318, F = 102.140 (p < 0.001) for step 2; ∆R2 = 0.005, F = 83.390 (p < 0.001) for step 3; ∆R2 < 0.001, F = 69.425 (p < 0.001) for step 4; ∆R2 = 0.006, F = 61.137 (p < 0.001) for step 5. b, unstandardized regression coefficient; β, standardized 1 regression coefficient; χ2, Chi-Square test statistic for model comparison to the previous step via LRT; OCI-R, Obsessive-Compulsive Inventory-Revised; a1 = male, 2 = female, b0 = no A-level, 1 = A-level and above.