Table 2.
Characteristics of offspring of bipolar disorder and major depressive disorder probands
| Bipolar disorder (n = 177) | Major depressive disorder (n = 502) | Analysis | ||||||
|---|---|---|---|---|---|---|---|---|
| t/Z/χ2 | df | Den.df | p-value | |||||
| Demographics | ||||||||
| Age, mean ± SD, [median, range] | 19.5 ± 10, [15.6, 10–50.9] | 19.0 ± 8.6 [16.6, 10–50.6] | 0.75 | 1 | 293 | 0.45 | ||
| Sex, male, n (%) | 81 (54.3) | 217 (50.1) | 0.77 | – | NAd | 0.44 | ||
| Race, white, n (%) | 93 (75.0) | 279 (70.1) | 0.22 | 1 | NA | 0.82 | ||
| Household income level (over $40,000/year), n (%) | 33 (26.0) | 81 (21.8) | 0.37 | 1 | NA | 0.71 | ||
| Educational level, mean ± SD, [median, range]a | 4.9 ± 1.2 [5, 1–7] | 4.8 ± 1.2 [5, 2–7] | 0.79 | 1 | NA | 0.43 | ||
| Married, n (%)b | 18 (30.5) | 60 (33.5) | 0.16 | 1 | NA | 0.87 | ||
| Clinical characteristics | ||||||||
| History of sexual abuse, n (%)c | 13 (10.7) | 48 (12.6) | 3.5 | 1 | NA | 0.06 | ||
| History of physical abuse, n (%)c | 13 (10.7) | 63 (16.5) | 6.9 | 1 | NA | < 0.01 | ||
SD = standard deviation; df = degrees of freedom.
Used proband data if offspring was under 18 years-of-age and offspring data if 18 or older. Education was rated as 7 = completed post-graduate training; 6 = completed college, received four-year academic degree; 5 = attended college, but did not receive four-year academic degree; 4 = completed high school, trade school, or other non-academic training requiring high school completion for admission; 3 = partial high school (10th or 11th grade); 2 = junior high school (7th, 8th, or 9th grade); 1 = less than 7th grade. (Mixed model did not converge; chi-squared test used.).
Used only data of offspring 18 years-of-age and older.
Likelihood ratio test based on mixed logistic regression adjusting for offspring sex.
Mixed model software in R does Z-test instead of F-test. In that case df is infinity.