I would have up to 8 independent variables (e.g., BMI, age, gender, educational level, psychological disorder, etc.), and I would measure these groups at two timepoints (pre- and post-treatment). The dependent variable which I would measure at these two timepoints would be a score on a questionnaire, a continuous DV (measuring complaints). I would like to examine differences between these groups with regards to treatment effects.

I expect the size of N not to be an issue due to a large amount of data in the database.

Would a mixed ANOVA work with multiple independent variables? Or otherwise a factorial ANOVA perhaps? These two tests seem best to me, but please feel free to advice me on the test you would recommend in this instance. Thank you!