Recent evidence suggests that lower urinary tract syndromes may be a manifestation of a systemic disorder in some cats with feline interstitial cystitis (FIC). Comorbid disorders are regularly identified in FIC cats and are evidenced by “sickness behaviors,” or changes in states of anxiety, increased or decreased food intake, vomiting/regurgitation, diarrhea, constipation, lower urinary tract signs, skin problems, anorexia, and respiratory signs. In this study, sickness behaviors were evaluated in donated, colony-housed FIC cats and compared with those of healthy laboratory cats. The study was performed to assess whether events that activate the stress response system could result in different levels of sickness behaviors between the 2 groups. Healthy neutered cats (n = 12) and cats with FIC (n = 20) were evaluated in the study. All cats were housed in an identical fashion and fed the same diet. Environmental enrichment occurred in the form of daily routine husbandry, individual playtime, toys, and classical music. Stressful events were defined as discontinuation of contact/interactions with the primary caregiver; changes in the time of day of routine husbandry; unfamiliar caretakers; feeding delays or food removal; restraint stress; anesthesia; and withdrawal of cage enrichment. The authors claimed 4 noteworthy findings:

• Husbandry and enrichment conditions in the colony were associated with decreases in sickness behaviors in FIC cats.

• Exposure to unusual events significantly increased the risk for elevated numbers of sickness behaviors in both groups.

• The most common sickness behaviors were decreased food intake and elimination problems.

• There was a correlation between older cats and risk for increase in sickness behaviors, although none of the cats was older than 8 years.

Commentary: This study supports the well-accepted hypothesis that stress may induce illness. Previous studies have suggested that cats with FIC or feline lower urinary tract disease (FLUTD) may have organic differences in their stress responses. Therefore, it is interesting that the cats in this study did not have a statistically different incidence in sickness behaviors; this may have occurred due to small sample size or stressful events that could not elicit sickness behaviors. The first conclusion by the authors may be better substantiated if this study had evaluated the difference between the presence and absence of environmental enrichment as a variable for sickness behavior. Overall, behavior of cats with elimination problems is intriguing and, as this study points out, clearly needs better elucidation.—Heather Troyer, DVM, Diplomate ABVP (Canine & Feline Practice)

Sickness behaviors in response to unusual external events in healthy cats and cats with feline interstitial cystitis. Stella JL, Lord LK, Buffington CAT. JAVMA 238:67-73, 2011.