TPH2 and Anxiety: Furthermore, in the marble burying test, likewise an anxiety paradigm, no difference in the number of marbles buried was observed (4.531 ± 0.6350 marbles for TPH2-CB1−/− [n = 32] and 5.938 ± 0.7239 marbles for TPH2-CB1+/+ [n = 32]; T62) = 1.490; p = 0.1492).