I used to think I could control ducks with my mind but it turns out ducks and I just have very similar ideas about what stuff ducks should do.” —Jacy Catlin 

Humans have this little quirk in their brains: when two things occur at nearly the same time we tend to think they are related, that one caused the other. Many times they really are: if you eat a sandwich that’s been sitting out in the sun all day and you get sick, blame the sandwich. That sandwich wanted you dead, man.

But if you wave your hand above your head in a big figure eight, say “peanuts and sausages” three times and then win the lottery, there’s no way that stuff is related. It may look like it is, and our brains really want to make it seem like your little ritual led to the big money win, but you know logically that these events are totally unrelated. Our propensity to link unrelated events like this (described by the Latin phrase post hoc, ergo propter hoc – afterwards, therefore because of) is the cause of much human misery and suffering, but is a byproduct of our big brains. It usually serves us pretty well by helping us avoid things like the sandwich of doom the next time. The scientific phrase that describes the mindset needed to avoid falling prey to this is correlation is not causation: just because two things happened together, or in quick succession, doesn’t necessarily mean they are linked.

This phenomenon is behind many of the crises facing modern medicine (of the human and veterinary variety) and also behind many of the irrational things that we humans do. The placebo effect, the adherence of many people to ideas and therapies that have been proved useless or false, the utterly unshakable belief that many have that a patient with a fever MUST always have antibiotics – all arise because of this tendency we have to link unlinked events. Many people have been led to the sometimes false conclusion that fevers go away due to antibiotics, not the body’s innate ability to heal itself, by the fact that the fever resolved after the course of antibiotics began. Every fever doesn’t need antibiotics because antibiotics only work on bacteria, and there are many causes for fever that aren’t caused by bacteria, such as viruses, like cancer, like immune disease, etc.

Many pet owners raise an eyebrow when I suggest waiting and watching to see if a subtle, non-specific symptom, such as a fever, goes away on its own instead of running a battery of tests or prescribing antibiotics. If we have a stable, comfortable patient, sometimes – not every time – waiting to see if either the condition goes away or elaborates into something we can more easily figure out is a reasonable option. If there’s anything in the picture that’s alarming, say a fever accompanied by abdominal pain, or history of diabetes, then further workup makes sense and is warranted. Also, some pet owners aren’t content to wait. For those, some form of action is helpful for them (not necessarily the patient), so in those cases I try to pick interventions and tests that don’t make things worse and may shed some light on what’s going on. But in many cases, my preference often is to wait and see.

Watchful waiting is the term that’s been applied to this tactic, and I think it’s served my patients well but may have confused the occasional pet owner. Watchful waiting can’t be applied in all instances and across all situations, though. In some cases, the effect of waiting can be disastrous, and to use it properly, clinicians have to have enough experience and intuition to have a feeling for how diseases and patients generally work. It requires a sense for what state the patient is in, how able the owners are to judge their pet for signs of worsening, and their ability to come in for follow-up care if needed. The one-year-old indoor cat with a runny nose who’s still eating and has smart owners who’ll come back within a day if things get worse will be offered watchful waiting; the one who lives 90 minutes away probably won’t.

The next time your vet talks to you about waiting to see if things will go away on their own, give it consideration. If your pet is not in a crisis, is still eating, active and not in pain, it might be a reasonable course of action.