am interested to look at anxiety changes over time using a database with multiple time points. Anxiety was measured every other week while patients were in a treatment program. They completed a post treatment assessment assessment and were then asked follow up questions every other month until 1 year after the treatment at which point they completed a 1 year follow up assessment.
So, I have:
PRE Treatment week 2 week 4...week 12 (POST Tretament) and then month 2 month 4...month 12
I'm interested to see if there are different curves between pre to posttretament and how these curves look at follow up (week 12 to month 12 or pre to post using the different timepoints).
The problem that I have is that anxiety was assessed using 3 items at each time point, so I can't use latent variables. Is there a way to get around this limitation and still look at change in the way I described? Perhaps a different type of analysis other than latent growth curve modelling? Or can I use the 3 items to create the latent variable somehow? I'm thinking there must be a way to deal with this issue.