Table 3

Patterns of use among adults with developmental disabilities who initiate antipsychotics between 1 April 2010 and 31 March 2016

CharacteristicOverall
n=6924
No psychiatric diagnosis
n=1863
Psychiatric diagnosis
n=5061
P value
Prescriber specialty of first antipsychotic prescription, n (%)
 Psychiatrist2015 (29.1)178 (9.6)1837 (36.3)<0.001
 Family practice3613 (52.2)1216 (65.3)2397 (47.4)<0.001
 Other603 (8.7)283 (15.2)320 (6.3)<0.001
 Missing693 (10.0)186 (10.0)507 (10.0)0.967
Antipsychotic dose*
Dose at initiation (median, IQR)80 (40–200)80 (40–200)80 (40–200)0.195
Maximum dose received (median, IQR)140 (50–300)110 (50–274)150 (57–300)<0.001
Patterns of discontinuation of any antipsychotic
Median time to discontinuation354 days230 days<0.001
Number (%) continuing for at least:
 6 months4022 (58.1)945 (50.7)3077 (60.8)<0.001
 1 year3347 (48.3)779 (41.8)2568 (50.7)<0.001
  • *Reported as chlorpromazine equivalents.

  • †Cannot be estimated because more than 50% of individuals continued treatment at end of study period.

  • ‡P value from log-rank test. All other p values reported are the result of χ2 tests.