I would like to expand on my previous inquiry and inquire about the factors that are necessary for establishing causal connections. Could you please give me some insights, perhaps using the case of late-life depression and sleep disruption as an example?

It would be my pleasure to assist you.

I appreciate your thorough response. Thank you very much.

Absolutely. From my perspective, there are three conditions that must be met to establish a causal relationship between late-life depression and sleep disruption among older adults. First, there must be a correlation between the two factors. Second, depression should occur prior to sleep problems. Third, there should be no other factor that can account for sleep disturbance. If these conditions are met, we can confidently assert that late-life depression causes sleep disruption.