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. Author manuscript; available in PMC: 2021 Oct 1.
Published in final edited form as: Mult Scler. 2020 Dec 14;27(11):1771–1780. doi: 10.1177/1352458520979304

Figure 3. Association Between Depression Severity and Processing Speed Z-score* by Age Group.

Figure 3.

*Z-scores were calculated from regression-based equations derived from a healthy volunteer study of individuals aged 18 to 89 (n=517) of MSPT outcomes, including processing speed. The mean for each neuroperformance outcome is equal to 0 and the standard deviation is equal to 1 among the healthy controls. Values presented denote a per SD difference in a given outcome. Mean differences are adjusted for race, ethnicity, education status, insurance, disease duration, DMTs class, antidepressant use, smoking status, and BMI. Estimates and error bars denote the difference in PST Z-scores between moderate-to-severe vs. no depressive symptoms (black; left of dotted line) and by age groups (pink; right of dotted line). Individuals reporting moderate to severe depressive symptoms had −0.35 SD lower PST- Z scores relative to those with mild to no depressive symptoms. This association was modified by age (p = 0.009). For example, 18yo-30yo’s with moderate to severe depression had −0.45 SD worse PST Z-scores relative to non-depressed individuals aged 18yo to 30yo (−0.45 SD; 95% CI: −0.62, −0.29). In comparison, moderate-to-severely depressed 60+yo’s have −0.20 SD worse PST Z-scores relative to non-depressed 60+yo’s (−0.20 SD; 95% CI: −0.32, −0.08).