Table 2.
Results from Exploratory Regression Analyses Predicting Within-Pair Differences in Neuropsychological Performance Between MD Probands and their Unaffected Cotwins
| Digit Symbol Substitution | Letter-Number Sequencing | Block Design | Verbal Paired Associates – Immediate | Verbal Paired Associates – Delayed | Vocabulary | |
|---|---|---|---|---|---|---|
| N Pairs | 25 | 38 | 26 | 40 | 38 | 40 |
| Pair Difference M | 1.44 | 0.05 | −0.04 | −0.08 | −0.13 | 2.48 |
| (SD) | 9.98 | 1.80 | 7.49 | 8.21 | 3.16 | 7.19 |
|
| ||||||
| Parameter Estimates (SE)
| ||||||
| Intercept | 2.8 (16.2) | 3.5 (2.1) | −7.7 (11.6) | −0.7 (9.0) | 1.5 (3.8) | 5.0 (8.7) |
| Age | −0.06 (0.3) | −0.07 (0.04) | −0.02 (0.2) | −0.06 (0.2) | −0.02 (0.07) | 0.01 (0.2) |
| Sex | −0.3 (4.5) | −0.7 (0.7) | −2.4 (3.2) | −4.5 (2.8) | −0.7 (1.1) | 4.9 (2.7) |
| Mode-Diff a | -- | −0.01 (0.6) | -- | 3.7 (2.4) | 0.9 (1.1) | −1.8 (2.3) |
| Early Onset | −10.7 (5.9) | −0.5 (0.8) | −4.2 (4.0) | −1.8 (3.3) | −0.1 (1.4) | 4.6 (3.2) |
| WorstSev | 0.2 (1.4) | 0.1 (0.2) | 1.7 (1.0) | 0.9 (0.7) | −0.1 (0.3) | −1.0 (0.6) |
| Mother MD | 5.3 (5.3) | −1.5 (0.7) | −4.3 (3.6) | −4.2 (2.8) | −1.1 (1.2) | −1.6 (2.7) |
| Father MD | 2.2 (7.7) | −0.5 (0.8) | 0.4 (5.2) | 8.8 (3.5) | 3.5 (1.4) | 1.0 (3.3) |
| Model R2 (%) | 20.8 | 26.2 | 26.2 | 32.8 | 28.1 | 19.2 |
Sex coded as Male=1. Mode= 1 if telephone assessment; Worst severity = # symptoms during worst episode. Early Onset=first episode before 18. Negative coefficients are in direction of worse performance by the Proband.
a
not applicable for BD and DSS; all twins with data were tested in person