I learned a new term this week:  “trigger-stacking.” I wasn’t attending a professional conference or catching up on my journals.  I heard the phrase from a veterinary behaviorist.

Six months ago we adopted Clifford, a three-year-old Australian Shepherd who had been a stray in rural New Jersey. Let’s just say the adjustment has been very rough.

During the three-hour drive from New Jersey, he draped himself across my lap, instantly claiming me as his ”person.” But he has what the Aussie rescue groups euphemistically call “a strong guardian instinct,” causing him to be overly protective of his turf, his food, his toys, and…me.  So from the moment he entered our house, he treated my husband as an enemy invader.

Whenever my husband crossed a threshold into a room I was in, Clifford launched a canine air-missile strike.  We began to feel under siege, on constant alert for the next attack.

Fast forward six months. Thankfully, through a combination of medication prescribed by the veterinary behaviorist and lots of counter-conditioning—which derives from the same learning principles underpinning the treatment approaches I use for anxiety—we now have a much more relaxed dog. I’ve stopped my Google searches for “Farms that Take Unadoptable Animals,” and Clifford has gradually been forming a tentative bond with my husband. We’re cautiously optimistic.

But because behavior modification isn’t linear, the aggressive displays we’ve been working so hard to eliminate will occasionally resurface.  And even though I should know better, I was disheartened one day last week to observe a spike in Clifford’s territorial barking along with his refusal to come back into the house after he went out in the yard while I was at work. He stood on the deck for two hours, nervously casting glances at my husband, who tried to lure him back inside with a smorgasbord of tasty treats. Even steak couldn’t entice him.

After reviewing the behavioral log I keep to remind myself of Clifford’s progress (a practice I heartily recommend, by the way, if you’re working on changing your own behavior), the cause of his regression became clear:  trigger-stacking.

I identified three major triggers, each of which individually heightened Clifford’s arousal and, cumulatively, pushed him over the edge: 1) A stressful visit to the vet for a vaccination the previous day; 2) Loud noises overhead while workmen repaired our roof; and 3) Repeated invasion of his territory while my husband walked in and out of his office moving books.

In hindsight, it makes perfect sense. But at the time, I had trouble convincing myself we weren’t back to square one.

When you experience an uptick in the anxiety or compulsive behaviors you’ve been working hard to manage, you might assume a setback means you haven’t made progress. Not so. A bad day at work, a fight with a partner, a sick child, a sleepless night—any one of those triggers might be manageable alone but in combination might just be too much to handle without reverting to the coping behaviors you’ve been trying to change.

So when you suffer a setback, don’t view it as a relapse. Instead, ask yourself if you’ve been facing more triggers than usual. Cut yourself some slack—but don’t make excuses to justify avoidance–by taking on lower intensity challenges, if necessary, to keep yourself from slipping back into old habits.

And, then, start back where you left off, as we did with Clifford. For a week, he continued to balk at coming inside whenever my husband let him out in the yard. But a few days ago, the sight of his leash brought him back in the house. And, for the first time, they walked around the block together.