Table 2. Clinical features and lifetime comorbidity in childhood- and adolescent-onset bipolar disorder

Childhood-onset

Adolescent-onset

   

n = 20

n = 23

c2

P

Age, mean (SD)

12.95 (3.4)

16.6 (1.3)

–4.73

0.0001

Age at onset, mean (SD)

9.85 (2.50)

14.39 (1.10)

–7.92

0.0001

Clinical global impression, mean (SD)

4.68 (0.759)

5 (0.80)

–1.31

ns

Bipolar disorder

       

Type I, n (%)

8 (40.0)

16 (69.6)

 

Type II, n (%)

12 (60.0)

7 (30.4)

3.79

0.051

Lifetime comorbidity, n (%)

       

Obsessive–compulsive disorder

8 (40.0)

11 (47.8)

0.27

ns

Social phobia

8 (40.0)

9 (39.1)

0.003

ns

Panic disorder or agoraphobia

4 (20.0)

7 (30.4)

0.61

ns

Separation anxiety disorder

3 (15.0)

4 (17.4)

0.04

ns

Generalized anxiety disorder

4 (20.0)

4 (17.4)

0.048

ns

Attention-deficit hyperactivity disorder or conduct disorder

10 (50.0)

2 (8.7)

9.07

0.003

Comorbid anxiety disorders, mean (SD)

1.3 (1.4)

1.5 (1.0)

–0.61

ns

Comorbid disorders, mean (SD)

2.1 (1.87)

1.61 (1.12)

0.95

ns

Pharmacologic hypomania, n (%)

7 (35.0)

5 (21.74)

0.93

ns

Index episode, n (%)

       

Depressive

11 (55.0)

7 (30.4)

 

(Hypo)mania

3 (15.0)

11 (47.8)

 

Mixed

6 (30.0)

5 (21.7)

5.37

ns (0.07)