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Table 2 Bipolar disorder (BD) in children and adolescents with and without diagnostic change after 3 years of follow-up (N = 478)

From: Diagnostic stability in children and adolescents with bipolar disorder, a nationwide register-based study

 Group with unchanged BD (N = 412)Group with diagnostic change (N = 66)RR (95% CI)p value
N (%)N (%)
Sex   0.038
 Female244 (89.1%)30 (10.9%)  
 Male168 (82.4%)36 (17.6%)1.61 (1.03; 2.53) 
Family history of psychiatric disorder   0.310
 Noa (87%)a (13%)  
 Yesa (84%)a (16%)1.27 (0.80; 2.03) 
Family history of BD   0.629
 Noa (86%)a (14%)  
 Yesa (88%)a (12%)0.82 (0.37; 1.18) 
Substance abuse (total)   0.286
 No373 (86.7%)57 (13.3%)  
 Yes39 (81.3%)9 (18.8%)1.41 (0.75; 2.68) 
Substance abuse of other than alcohol and cannabis   0.001
 No397 (87.3%)58 (12.7%)  
 Yes15 (65.2%)8 (34.8%)2.73 (1.48; 5.02) 
Diagnostic setting   0.015
 Outpatient or ER259 (89.3%)31 (10.7%)  
 Inpatient153 (81.4%)35 (18.6%)1.74 (1.11; 2.73) 
Psychotic BD at index   0.055
 No340 (87.6%)48 (12.4%)  
 Yes72 (80.0%)18 (20.0%)1.62 (0.99; 2.64) 
Index BD prior to 2005   0.988
 No300 (86.2%)48 (13.8%)  
 Yes112 (86.2%)18 (13.8%)1.00 (0.61; 1.66) 
Index BD < 13 years    
 No384 (86.1%)62 (13.9%)  
 Yes> 27 (–%)1< 5 (–%)1aa
Latest psychiatric diagnosis prior to BD
 Schizophrenia or related diagnosis   < 0.0001
  No355 (90.6%)37 (9.4%)  
  Yes57 (66.3%)29 (33.7%)3.57 (2.33; 5.47) 
 Affective disorders   0.568
  No313 (86.7%)48 (13.3%)  
  Yes99 (84.6%)18 (15.4%)1.16 (0.70; 1.91) 
 Substance abuse   0.655
  No381 (86.4%)60 (13.6%)  
  Yes31 (83.8%)6 (16.2%)1.19 (0.55; 2.57) 
 Other psychiatric disorders   0.134
  No191 (88.8%)24 (11.2%)  
  Yes221 (84.0%)42 (16.0%)1.43 (0.90; 2.29) 
Information about parents (N = 473)
 Schizophrenia or related diagnosis   0.003
  Noa (88%)a (12%)  
  Yesa (72%)a (28%)2.26 (1.32; 3.90) 
 Affective disorders   0.680
  Noa (87%)a (13%)  
  Yesa (85%)a (15%)1.12 (0.66; 1.91) 
 Substance abuse   0.928
  Noa (86%)a (14%)  
  Yesa (86%)a (14%)1.03 (0.55; 1.92) 
 Other psychiatric disorders   0.438
  Noa (86%)a (14%)  
  Yesa (> 55%)a (< 45%)1.64 (0.47; 5.68) 
 Mean (SD)Mean (SD)RR (95% CI)p-value
Age at first ever BD diagnosis (N = 478)15.9 (2.1)16.0 (2.1)1.01 (0.91; 1.13)0.857
Age at first psychiatric contact (N = 478)14.4 (3.5)14.0 (4.3)0.98 (0.92; 1.04)0.465
  1. aThe exact numbers could not be reported in order to comply with the data protection rules set by Statistics Denmark in order to avoid allowing identification of individual patients in cells containing ≤ 5 patients