Include two correlated factors in mixed model?

In my experiment in which participants make a yes-no decision, I use two measures of empathy because I predict these to be both of influence. The two questionnaire scales are weakly correlated but do not measure exactly the same. Can I include these two scales in my mixed model ANOVA or will they sort of average each other out and should I, if I want to use both measures of empathy run two separate models?

MIXED decision BY treatment target WITH empathic_concern perspective_taking
/CRITERIA=CIN(95) MXITER(100) MXSTEP(10) SCORING(1) SINGULAR(0.000000000001) HCONVERGE(0, ABSOLUTE) LCONVERGE(0, ABSOLUTE) PCONVERGE(0.000001, ABSOLUTE)
/FIXED=treatment target empathic_concern perspective_taking
treatment * target perspective_taking
treatment * empathic_concern
treatment * perspective_taking
empathic_concern * perspective_taking
treatment * perspective_taking * empathic_concern
| SSTYPE(3)
/METHOD=ML
/PRINT=CORB DESCRIPTIVES  SOLUTION
/RANDOM=INTERCEPT | SUBJECT(id) COVTYPE(VC)
/EMMEANS=TABLES(OVERALL).

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