Table 2.

Change over time in z-scored neuropsychological domains between groups defined by age of onset of initial depressive episode

Domain	Difference in 1-Year Change	Standard Error	Test Statistic and Effect Size	p value
Episodic Memory			F2,1761 = 17.35 ES = 0.018	< 0.0001
• EOD - Nondepressed	−0.0323	0.0055	t = −5.84	< 0.0001
• LOD – Nondepressed	−0.0084	0.0065	t = −1.31	0.1913
• EOD – LOD	−0.0239	0.0069	t = −3.46	0.0006
Attention-Working Memory			F2,1558 = 17.35 ES = 0.018	<0.0001
• EOD - Nondepressed	−0.0414	0.0071	t = −5.80	< 0.0001
• LOD – Nondepressed	−0.0241	0.0082	t = −2.94	0.0033
• EOD – LOD	−0.0173	0.0088	t = −1.96	0.0500
Verbal Fluency			F2,1779 = 8.15 ES = 0.007	0.0003
• EOD - Nondepressed	−0.0248	0.0065	t = −.78	0.0002
• LOD – Nondepressed	0.0003	0.0077	t = 0.03	0.9740
• EOD – LOD	−0.0250	0.0082	t = −3.06	0.0023
Executive Function			F2,1718 = 17.59 ES = 0.022	< 0.0001
• EOD - Nondepressed	−0.0314	0.0063	t = −5.02	< 0.0001
• LOD – Nondepressed	0.0094	0.0073	t = 1.30	0.1952
• EOD – LOD	−0.0408	0.0079	t = −5.20	< 0.0001

Reported data are statistical results of the interaction between onset of depression (EOD or early-onset before age 50y; LOD or late-onset age 50y or later; or nondepressed) and study time, examining Z-transformed cognitive domain scores as the dependent variable. Models controlled for age, sex, race, education, and baseline domain score. Degrees of freedom for F statistics displayed as 2 (for the three groups), model error. T values determined from group comparisons within the models. ES = effect size