These two different ways to assess how adiposity changes over time highlights differences between traits that are conceptually and empirically related. For example, trait anxiety and trait depression are highly correlated (r = .66 in the current sample), but anxiety and depression are distinguishable constructs that have unique correlates (Watson et al., 1995). And, indeed, depression and anxiety had different longitudinal associations with BMI: Depression was associated with weight fluctuations, anxiety was not. Interestingly, the depression facet of Neuroticism measures the susceptibility to negative mood, not the physical symptoms of depressed mood (e.g., changes in appetite). Yet, this trait had the expected relation with weight fluctuations, but was unrelated to a systematic increase in weight. In contrast, the physical manifestations of anxiety do not include changes in appetite, and this trait was not associated with weight fluctuations or systematic increases in weight over time.
