Table 5. Hazard Ratios (HR) for Time-of-Onset of Mental Health Problems for Subsequent Work Disability, Comparing Early-Onset With Later-Onset Cases.

Mental health issue	Whole cohort^a			Exposure-discordant twins^a
Mental health issue	No.	HR (95% CI)	P value	No. pairs	HR (95% CI)	P value
Internalizing problems
Later-onset	148	1 [Reference]	.50	21	1 [Reference]	.78
Early-onset	266	1.16 (0.76-1.76)	.50	21	1.17 (0.39-3.47)	.78
Externalizing problems
Later-onset	173	1 [Reference]	.22	17	1 [Reference]	.76
Early-onset	240	1.29 (0.86-1.91)	.22	17	0.83 (0.25-2.73)	.76
Internalizing and/or externalizing problems
Later-onset	225	1 [Reference]	.13	33	1 [Reference]	.83
Early-onset	392	1.32 (0.92-1.88)	.13	33	1.10 (0.47-2.59)	.83

^{^a}

Including complete cases (ie, participants assessed at all 4 waves of measurements).