Demographic characteristics
| Characteristic | Bipolar disorder and lifetime cannabis use n = 40 | Bipolar disorder and no history of cannabis use n = 31 | Healthy controls n = 63 | Test statistic | p value | Effect size |
|---|---|---|---|---|---|---|
| Age, yr | 17.49 ± 1.25 | 17.39 ± 1.91 | 16.90 ± 1.63 | F = 2.03 | 0.14 | η2 = 0.03 |
| Female | 25 (62.5) | 19 (61.3) | 34 (54.0) | χ2 = 0.89 | 0.64 | V = 0.08 |
| Socioeconomic status* | 4.20 ± 0.97 | 4.35 ± 0.80 | 4.37 ± 0.87 | H = 0.76 | 0.68 | η2 = 0.01 |
| Race or ethnicity, White | 31 (77.5) | 23 (74.2) | 32 (50.8) | χ2 = 9.35 | 0.009§¶ | V = 0.26 |
| Intact family | 22 (55.0) | 21 (67.7) | 42 (66.7) | χ2 = 1.76 | 0.42 | V = 0.12 |
| Tanner stage† | 4.48 ± 0.64 | 4.39 ± 0.67 | 4.29 ± 0.61 | H = 2.77 | 0.25 | η2 = 0.02 |
| Body mass index (adjusted), kg/m2 | 24.46 ± 4.41 | 23.57 ± 4.77 | 21.91 ± 3.69 | H = 11.11 | 0.004§ | η2 = 0.08 |
| Children’s Global Assessment Scale score | ||||||
| Most severe previous episode | 43.30 ± 8.95 | 44.73 ± 8.91 | — | U = 643.50 | 0.60 | d = 0.16 |
| Highest score in past year‡ | 67.33 ± 12.34 | 69.90 ± 10.68 | 89.48 ± 5.07 | F = 93.47 | < 0.001§¶ | η2 = 0.58 |
| Score in past month‡ | 64.18 ± 11.81 | 65.90 ± 11.28 | 89.49 ± 4.53 | F = 132.93 | < 0.001§¶ | η2 = 0.66 |
Values are reported as mean ± standard error or n (%).
↵* Based on the Hollingshead Four Factor Index.33
↵† Measured on a scale of 1 to 5.
↵‡ Homogeneity of variance violated; Welsh test reported.
↵§ Significant at p < 0.05 (adolescents with bipolar disorder and lifetime cannabis use v. healthy controls).
↵¶ Significant at p < 0.05 (adolescents with bipolar disorder and no history of cannabis use v. healthy controls).