Having lived with two abys for almost 15 years I'd say the signs are there. Mine not only reeked havoc all night, knocking things off the night table, especially half full glasses of water cause they know that gets immediate attention, attacking tomatoes and loaves of bread and wrestling them to the ground, bringing me 20 dollar bills my husband has left in pockets and taking him my rumpled up visa bills,,,,the good news is they slowed down at 12 and 13 years of age cause they couldn't jump to the top of the fridge anymore and land on your shoulder as you innocently walked by... all this trouble without the aid of catnip..... they're gone now and I so miss all their antics and affection.