This might be useful:
Why Do only some Cats Get FIC?
We know that cats that get this syndrome have a unique imbalance in the way their brain controls hormones. These cats are neurologically different in a way that makes them extra reactive to any change in their world, extra anxious, and extra sensitive to pain relating to the back half of their bodies. They are different from other cats but as long as they live in a predictable environment with the same food, same schedule, private food, rest and toilet resources etc., you might never know you had a sensitive feline in the family. Typical or common triggers for FIC might include:
Stress among the humans in the home (final exams, arguments, sickness etc)
Someone (or another animal) moving in or out
Construction in the home or outdoors
Weather change or earthquake
New furniture
Moving to a new home
Changing to a new brand of food
Humans changing schedules as to when they are home.
FIC cats are very sensitive and can flare up with symptoms over events that humans frequently discount or pay no attention to. Most pet owners, however, are aware that the cat in question has a personality that is somewhat anxious or sensitive.
Preventing Future Episodes
Environmental Enrichment
Many people are surprised to find that environmental enrichment is effective in preventing future FIC episodes. You might think your cat has plenty of toys and seems relaxed and well-adjusted but reality is that the cat's natural environment of living in the forest and hunting/eating mice regularly throughout the day is a far cry from sitting on a sofa, eating processed foods, and eliminating waste in a plastic box filled with clay. Most cats are fine with the domestic lifestyle but the FIC cat is special and has special sensitivity. Stress can be minimized by allowing choices for the cat in terms of areas for playing, resting, eating, and eliminating. Just providing more toys is unlikely to be adequate. Most of the time the cat in question needs a private area for "me time" (separate feeding, rest, and/or toileting area).
The American Association of Feline Practitioners has published a set of guidelines for an enriched feline environment. The bottom line is:
Each cat should have the opportunity to play with the owner or with another cat if desired.
Each cat should be able to move freely about its home including climbing if desired.
Scratching posts should be available.
Toys should be regularly rotated/replaced.
Each cat should be able to choose warmer and cooler areas within the home.
There should be a litter box for each cat, ideally plus one extra. Litter boxes should be located in well-ventilated areas and should be kept clean. Boxes should be washed out weekly with a minimally scented detergent. Unscented clumping litter seems to be best. If there is more than one floor in the home, there should be a box on each floor.
Litter boxes should be private enough that other animals will not be bothering the cat and loud appliances will not startle the cat during litter box use.
Each cat should have his own food and water bowls. Feeding/watering stations should be safe so that other animals (like dogs) will not be startling the cat. Bowls should be washed daily.
The brand, flavor, or format of the food (dry vs canned) should be kept fairly constant. If it is changed, allow the cat a choice of new food vs. old food at least for a while before changing over and do not change more than once a month.