Intellectual Disability and Psychotic Disorders in Children: Association With Maternal Severe Mental Illness and Exposure to Obstetric Complications in a Whole-Population Cohort
Abstract
Objective:
Method:
Results:
Conclusions:
Method
Study Population
Outcome Variable: Intellectual Disability
Psychotic Disorders in Children
Exposure Variables
Maternal severe mental illness.
Obstetric complications.
Other covariates.
Data Analyses
Results
Sample Characteristics
Children With Intellectual Disability | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|
Total Cohort (N=464,580) | Maternal Severe Mental Illness (N=15,351) | Maternal Schizophrenia (N=1,653) | Any (N=6,217) | Genetic Basis (N=860) | ||||||
Characteristic | N | % | N | % | N | % | N | % | N | % |
Child with intellectual disability | 6,217 | 1.3 | 510 | 3.3 | 77 | 4.7 | ||||
Child with intellectual disability and information on the cause | 3,179 | 262 | 43 | |||||||
Child with intellectual disability of a genetic basis | 860 | 0.2 | 54 | 0.4 | 7 | 0.4 | ||||
Exposure to obstetric complications of critical severity | ||||||||||
During pregnancy | 125,542 | 27.0 | 5,239 | 34.1 | 541 | 32.7 | 2,380 | 38.3 | 406 | 47.2 |
During labor and delivery | 219,934 | 47.3 | 7,551 | 49.2 | 777 | 47.0 | 3,311 | 53.3 | 439 | 51.0 |
During the neonatal period | 200,665 | 43.2 | 7,720 | 50.3 | 865 | 52.3 | 3,768 | 60.6 | 636 | 74.0 |
During pregnancy, labor and delivery, or the neonatal period | 327,452 | 70.5 | 11,552 | 75.3 | 1,232 | 74.5 | 5,013 | 80.6 | 749 | 87.1 |
Sex | ||||||||||
Male | 238,381 | 51.3 | 7,962 | 51.9 | 875 | 52.9 | 3,937 | 63.3 | 486 | 56.5 |
Female | 226,199 | 48.7 | 7,389 | 48.1 | 778 | 47.1 | 2,280 | 36.7 | 374 | 43.5 |
Maternal age (years) | ||||||||||
≤19 | 25,979 | 5.6 | 1,557 | 10.1 | 198 | 12.0 | 574 | 9.2 | 36 | 4.2 |
20–34 | 389,483 | 83.8 | 12,341 | 80.4 | 1,249 | 75.6 | 4,957 | 79.7 | 663 | 77.1 |
≥35 | 49,102 | 10.6 | 1,453 | 9.5 | 206 | 12.5 | 686 | 11.0 | 161 | 18.7 |
Unknown | 16 | 0.6 | ||||||||
Maternal place of birth | ||||||||||
Outside Australia | 136,016 | 29.3 | 3,632 | 23.7 | 382 | 23.1 | 1,551 | 24.9 | 284 | 33.0 |
Australia | 327,560 | 70.5 | 11,679 | 76.1 | 1,267 | 76.6 | 4,650 | 74.8 | 576 | 67.0 |
Unknown | 1,004 | 0.2 | 40 | 0.3 | 4 | 0.2 | 16 | 0.3 | ||
Father’s age (years) | ||||||||||
≤19 | 6,553 | 1.4 | 363 | 2.4 | 45 | 2.7 | 155 | 2.5 | 10 | 1.2 |
20–54 | 435,934 | 93.8 | 13,174 | 85.8 | 1,211 | 73.3 | 5,437 | 87.5 | 813 | 94.5 |
≥55 | 1,034 | 0.2 | 43 | 0.3 | 3 | 0.2 | 27 | 0.4 | 5 | 0.6 |
Unknown | 17,795 | 3.8 | 1,577 | 10.3 | 356 | 21.5 | 532 | 8.6 | 29 | 3.4 |
Father unknown | 3,264 | 0.7 | 194 | 1.3 | 38 | 2.3 | 66 | 1.1 | 3 | 0.3 |
Father’s place of birth (if the father is known) | ||||||||||
Outside Australia | 140,099 | 30.2 | 3,741 | 24.4 | 423 | 25.6 | 1,615 | 26.0 | 285 | 33.1 |
Australia | 303,189 | 65.3 | 9,837 | 64.1 | 835 | 50.5 | 4,004 | 64.4 | 543 | 63.1 |
Unknown | 18,028 | 3.9 | 1,579 | 10.3 | 357 | 21.6 | 532 | 8.6 | 29 | 3.4 |
Birth cohort | ||||||||||
1980–1982 | 56,062 | 12.1 | 1,938 | 12.6 | 266 | 16.1 | 395 | 6.4 | 109 | 12.7 |
1983–1986 | 80,197 | 17.3 | 2,744 | 17.9 | 327 | 19.8 | 1,099 | 17.7 | 177 | 20.6 |
1987–1992 | 130,685 | 28.1 | 4,478 | 29.2 | 511 | 30.9 | 2,469 | 39.7 | 261 | 30.3 |
1993–1996 | 87,708 | 18.9 | 2,917 | 19.0 | 277 | 16.8 | 1,346 | 21.7 | 152 | 17.7 |
1997–2001 | 109,928 | 23.7 | 3,274 | 21.3 | 272 | 16.5 | 908 | 14.6 | 161 | 18.7 |
Birth order | ||||||||||
1 | 180,960 | 39.0 | 5,449 | 35.5 | 628 | 38.0 | 2,241 | 36.0 | 297 | 34.5 |
2 | 156,878 | 33.8 | 4,795 | 31.2 | 496 | 30.0 | 1,853 | 29.8 | 256 | 29.8 |
3 | 80,423 | 17.3 | 2,842 | 18.5 | 281 | 17.0 | 1,151 | 18.5 | 166 | 19.3 |
≥4 | 46,319 | 10.0 | 2,265 | 14.8 | 248 | 15.0 | 972 | 15.6 | 141 | 16.4 |
Mother’s marital status at time of child’s birth | ||||||||||
Married or de facto marriage | 422,622 | 91.0 | 12,321 | 80.3 | 1,110 | 67.2 | 5,190 | 83.5 | 787 | 91.5 |
Single or other | 41,697 | 9.0 | 3,006 | 19.6 | 539 | 32.6 | 1,023 | 16.5 | 73 | 8.5 |
Unknown | 261 | 0.1 | 24 | 0.2 | 4 | 0.2 | 4 | 0.1 | ||
Socioeconomic index of mother’s residence at time of child’s birth | ||||||||||
Lowest quintile (most disadvantaged) | 90,433 | 19.5 | 4,322 | 28.2 | 581 | 35.1 | 1,854 | 29.8 | 161 | 18.7 |
Second quintile | 102,855 | 22.1 | 3,801 | 24.8 | 399 | 24.1 | 1,479 | 23.8 | 202 | 23.5 |
Third quintile | 90,257 | 19.4 | 2,869 | 18.7 | 274 | 16.6 | 1,139 | 18.3 | 167 | 19.4 |
Fourth quintile | 83,589 | 18.0 | 2,315 | 15.1 | 208 | 12.6 | 884 | 14.2 | 145 | 16.9 |
Highest quintile (least disadvantaged) | 94,502 | 20.3 | 1,968 | 12.8 | 184 | 11.1 | 823 | 13.2 | 179 | 20.8 |
Missing data | 2,944 | 0.6 | 76 | 0.5 | 7 | 0.4 | 38 | 0.6 | 6 | 0.7 |
Remoteness of mother’s residence at time of child’s birth | ||||||||||
Major city | 308,520 | 66.4 | 8,991 | 58.6 | 1,086 | 65.7 | 4,087 | 65.7 | 588 | 68.4 |
Inner regional | 45,047 | 9.7 | 1,625 | 10.6 | 122 | 7.4 | 590 | 9.5 | 85 | 9.9 |
Outer regional | 56,136 | 12.1 | 2,564 | 16.7 | 222 | 13.4 | 772 | 12.4 | 104 | 12.1 |
Remote | 35,842 | 7.7 | 1,466 | 9.5 | 140 | 8.5 | 495 | 8.0 | 61 | 7.1 |
Very remote | 18,853 | 4.1 | 704 | 4.6 | 82 | 5.0 | 272 | 4.4 | 22 | 2.6 |
Missing data | 182 | 0.0 | 1 | 0.0 | 1 | 0.0 | ||||
Indigenous status: of Aboriginal or Torres Strait Islander descent | 30,551 | 6.6 | 2,056 | 13.4 | 354 | 21.4 | 871 | 14.0 | 42 | 4.9 |
Mother with an intellectual disability | 712 | 0.2 | 273 | 1.8 | 97 | 5.9 | 153 | 2.5 | 10 | 1.2 |
Father with an intellectual disability | 532 | 0.1 | 46 | 0.3 | 7 | 0.4 | 99 | 1.6 | 7 | 0.8 |
Father with any mental health contact other than for a psychotic disorder | 45,538 | 9.8 | 2,801 | 18.2 | 305 | 18.5 | 1,066 | 17.1 | 111 | 12.9 |
Father with any diagnosis of a psychotic disorder | 7,779 | 1.7 | 769 | 5.0 | 103 | 6.2 | 187 | 3.0 | 19 | 2.2 |
Child’s conception after the mother’s diagnosis of severe mental illness | 3,161 | 20.6 | 676 | 40.9 | 2,380 | 38.3 | 13 | 1.5 |
Child Intellectual Disability by Maternal Severe Mental Illness
Intellectual Disability and Maternal Severe Mental Illness | Unadjusted | Model 1 | Model 2 | |||
---|---|---|---|---|---|---|
Odds Ratio | 95% CI | Odds Ratio | 95% CI | Odds Ratio | 95% CI | |
Any intellectual disability | ||||||
Child with heightened risk | ||||||
Any maternal severe mental illness | 2.7 | 2.4, 3.0 | 2.0 | 1.8, 2.3 | 1.7 | 1.5, 1.9 |
Schizophrenia | 3.8 | 3.0, 4.9 | 2.4 | 1.9, 3.2 | 1.7 | 1.3, 2.3 |
Bipolar disorder | 2.0 | 1.6, 2.5 | 1.6 | 1.3, 2.1 | 1.3b | 1.0, 1.7 |
Unipolar major depression | 2.6 | 2.3, 3.0 | 2.0 | 1.8, 2.4 | 1.9 | 1.6, 2.1 |
Other psychoses | 3.4 | 2.5, 4.6 | 2.3 | 1.7, 3.1 | 1.8 | 1.3, 2.4 |
Child with generic risk | Reference | Reference | Reference | |||
Intellectual disability of genetic basis | ||||||
Child with heightened risk | ||||||
Any maternal severe mental illness | 2.0 | 1.5, 2.7 | 1.8 | 1.3, 2.4 | 1.6 | 1.2, 2.2 |
Schizophrenia | 2.4 | 1.2, 5.1 | 2.1b | 1.0, 4.4 | 1.6 | 0.7, 3.6 |
Bipolar disorder | 1.5 | 0.8, 2.9 | 1.3 | 0.7, 2.6 | 1.2 | 0.6, 2.3 |
Unipolar major depression | 2.3 | 1.5, 3.1 | 2.1 | 1.4, 3.0 | 2.0 | 1.3, 2.9 |
Other psychoses | 1.1 | 0.4, 3.4 | 0.9 | 0.3, 2.9 | 0.8 | 0.3, 2.5 |
Child with generic risk | Reference | Reference | Reference |
Child Intellectual Disability by Maternal-Specific Diagnosis
Combined Effect of Exposure to Maternal Severe Mental Illness and Obstetric Complications
Intellectual Disability and Exposure to Obstetric Complications | Unadjusted | Model 1 | Model 2 | |||
---|---|---|---|---|---|---|
Odds Ratio | 95% CI | Odds Ratio | 95% CI | Odds Ratio | 95% CI | |
Any intellectual disability | ||||||
Obstetric complications | ||||||
Pregnancy | 1.7 | 1.6, 1.8 | 1.4 | 1.3, 1.5 | 1.4 | 1.3, 1.5 |
Labor and delivery | 1.3 | 1.2, 1.3 | 1.1 | 1.1, 1.2 | 1.1b | 1.0, 1.2 |
Neonatal | 2.0 | 1.9, 2.2 | 1.7 | 1.6, 1.8 | 1.7 | 1.6, 1.8 |
Any | 1.8 | 1.6, 1.9 | 1.7 | 1.6, 1.8 | 1.7 | 1.6, 1.8 |
No exposure of critical severity | Reference | Reference | Reference | |||
Intellectual disability of genetic basis | ||||||
Obstetric complications | ||||||
Pregnancy | 2.4 | 2.1, 2.8 | 1.9 | 1.6, 2.1 | 1.9 | 1.6, 2.1 |
Labor and delivery | 1.2b | 1.0, 1.3 | 0.9 | 0.8, 1.0 | 0.9 | 0.8, 1.0 |
Neonatal | 3.8 | 3.2, 4.4 | 3.4 | 2.9, 4.0 | 3.4 | 2.9, 3.9 |
Any | 2.8 | 2.3, 3.5 | 2.9 | 2.3, 3.5 | 2.9 | 2.3, 3.5 |
No exposure of critical severity | Reference | Reference | Reference |
Intellectual Disability of Genetic Basis
Psychotic Disorders in Children
Outcome | Mother With Schizophrenia | Children With Generic Risk | ||||||
---|---|---|---|---|---|---|---|---|
Children With Intellectual Disability | Children Without Intellectual Disability | Children With Intellectual Disability | Children Without Intellectual Disability | |||||
N | % | N | % | N | % | N | % | |
Child with psychotic disorder | 10 | 24.4 | 86 | 6.5 | 159 | 4.0 | 4,717 | 1.1 |
Child with no mental illness | 31 | 75.6 | 1,236 | 93.5 | 3,843 | 96.0 | 415,286 | 98.9 |
Total | 41 | 100.0 | 1,322 | 100.0 | 4,002 | 100.0 | 420,003 | 100.0 |
Discussion
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