Just wondering why they say an improvement in sleep or appetite is a good indication that an antidepressant is working in the early stages? Are these affected by serotonin in some way? I am only on day 16 of lexapro and I did notice a slight lift to start with on this med, sleep and appetite did improve a bit. My mood is still low and I feel anxious but I know it's early days. Are there any other symptoms known to improve with depression/anxiety first?