Specifically, a recent study found that males and not female PACAP−/− mice demonstrated increased anxiety-like behavior in the elevated plus maze in mecamylamine-induced nicotine withdrawal (Nega et al., 2020), suggesting males may be more sensitive to perturbations in the endogenous PACAP system as they relate to anxiety during nicotine withdrawal. The gene discussed is ADCYAP1; the disease is Anxiety.