Table 4. Incidence of Psychiatric Comorbidities in the Trajectories From Attention-Deficit/Hyperactivity Disorder to Schizophreniaa.
| Comorbidities | Patients, No. (%) | Sum of follow-up duration, y | Incidence rate (per 100 person-years) |
|---|---|---|---|
| All patients (n = 4506) | |||
| No incidence of psychiatric comorbidities | 1152 (26.21) | 2180.47 | 52.83 |
| Incidence of psychiatric comorbidities | 3244 (73.79) | NA | NA |
| Depression | 2023 (46.02) | 8212.54 | 24.63 |
| Anxiety disorder | 1326 (30.16) | 5982.72 | 22.16 |
| Tic disorder | 885 (20.13) | 3242.29 | 27.30 |
| Intellectual disability | 531 (12.08) | 2420.55 | 21.94 |
| Conduct disorder | 737 (16.77) | 3042.79 | 24.22 |
| ASD | 295 (6.71) | 1253.52 | 23.53 |
| Bipolar disorder | 1090 (24.80) | 4570.68 | 23.85 |
| OCD | 238 (5.41) | 1108.09 | 21.48 |
| SUD | 55 (1.25) | 293.62 | 18.73 |
| Aged 5-9 y (n = 2583) | |||
| No incidence of psychiatric comorbidities | 707 (28.16) | 1261.81 | 56.03 |
| Incidence of psychiatric comorbidities | 1804 (71.84) | NA | NA |
| Depression | 1027 (40.90) | 4213.79 | 24.37 |
| Anxiety disorder | 646 (25.73) | 2876.00 | 22.46 |
| Tic disorder | 676 (26.92) | 2487.79 | 27.17 |
| Intellectual disability | 313 (12.47) | 1480.25 | 21.15 |
| Conduct disorder | 465 (18.52) | 2025.13 | 22.96 |
| ASD | 201 (8.00) | 835.35 | 24.06 |
| Bipolar disorder | 552 (21.98) | 2398.58 | 23.01 |
| OCD | 103 (4.10) | 533.12 | 19.32 |
| SUD | 12 (0.48) | 69.00 | 17.39 |
| Aged 10-14 y (n = 1380) | |||
| No incidence of psychiatric comorbidities | 308 (22.76) | 711.49 | 43.29 |
| Incidence of psychiatric comorbidities | 1045 (77.24) | NA | NA |
| Depression | 726 (53.66) | 3007.07 | 24.14 |
| Anxiety disorder | 489 (36.14) | 2366.80 | 20.66 |
| Tic disorder | 191 (14.12) | 680.84 | 28.05 |
| Intellectual disability | 176 (13.01) | 759.94 | 23.16 |
| Conduct disorder | 238 (17.59) | 889.56 | 26.75 |
| ASD | 83 (6.13) | 339.11 | 24.48 |
| Bipolar disorder | 407 (30.08) | 1677.16 | 24.27 |
| OCD | 85 (6.28) | 384.39 | 22.11 |
| SUD | 27 (2.00) | 150.96 | 17.89 |
| Aged 15-19 y (n = 543) | |||
| No incidence of psychiatric comorbidities | 137 (25.75) | 207.17 | 66.13 |
| Incidence of psychiatric comorbidities | 395 (74.25) | NA | NA |
| Depression | 286 (53.76) | 996.77 | 28.69 |
| Anxiety disorder | 198 (37.22) | 742.31 | 26.67 |
| Tic disorder | 27 (5.08) | 76.44 | 35.32 |
| Intellectual disability | 47 (8.83) | 181.54 | 25.89 |
| Conduct disorder | 40 (7.52) | 129.92 | 30.79 |
| ASD | 19 (3.57) | 81.39 | 23.34 |
| Bipolar disorder | 140 (26.32) | 497.35 | 28.15 |
| OCD | 51 (9.59) | 190.90 | 26.72 |
| SUD | 16 (3.01) | 73.65 | 21.72 |
Abbreviations: ASD, autism spectrum disorder; NA, not applicable; OCD, obsessive-compulsive disorder; SUD, substance use disorder.
a
This analysis is conducted only in patients who received a schizophrenia diagnosis without psychiatric comorbidity at baseline.