I second this.

I take antihistamines from April to September. Loratadin absolutely has a negative effect on my mood. Mostly because I feel tired I believe. Switched to Ebastin and no more tiredness. However, I am starting to suspect that it also does affect my mood in some way or another.

During winter I take a pill as a precautionary if I’m going to be in any dusty spaces. The day after I sometimes experience mood swings that I cannot explain.