A lot of women ask this question, but interestingly, there isn’t a clear-cut "yes" or "no" answer to it. Put simply, it depends. The individual effects of hormones are unpredictable, so while one woman may feel better breastfeeding, another woman’s baby blues might actually get worse.
There are also other factors to consider. For example, if breastfeeding is extremely painful for you, then weaning baby might actually help improve your mood. Also, chronic sleep deprivation can cause postpartum depression because your serotonin levels (which control your mood) decrease when you don’t get enough sleep. If you’re waking up every two hours to breastfeed, you might actually prolong your baby blues if you’re sensitive to sleep deprivation. This is why it's so essential that breastfeeding moms make sure they get at least a few hours of uninterrupted sleep several nights each week. It’s also important that when you do wean, you do it very slowly — especially if you’re sensitive to hormone shifts. This will help to keep your moods more stable than if you’d wean abruptly.