Unless rewards are constantly getting bigger and more exciting, even the best experiences pale over time when repeated.

By Maia Szalavitz

(Photo: John Moore/Getty Images)

Disappointment is one of my least favorite emotions, and I know I’m not alone in my hatred of it. Among people with addiction, dashed hopes are a common trigger for relapse. And even if you’ve never been addicted, it’s quite tempting to respond to an unexpected loss, failure, or rejection by having a drink or two.

In fact, the connection between disappointment and addiction is a deep, neurological one — and it’s likely driven by the same critical neurotransmitter: dopamine.

If you’ve heard of dopamine at all — and at this point, what person concerned with addiction hasn’t? — you’ve probably heard it described as a “pleasure” or “reward” chemical. Cartoonish depictions of dopamine as the driver of addiction — with high dopamine signaling euphoria and low dopamine signaling withdrawal — abound. But it’s actually far more complicated — and much more intriguing in a way that is directly linked to the extreme displeasure of disappointment.

To start, dopamine isn’t completely unrelated to pleasure. However, its action in the motivational circuitry of the brain only plays a role in one type of positive experience: the joy of desire.

Here, dopamine rises when we anticipate good things, but not necessarily when we get them. Dopamine pleasures are exciting, motivating, exhilarating — not relaxing, grounding, or calming: basically, stimulant highs rather than those from depressants. The pleasures of satisfaction, in fact, are linked, instead, to the brain’s opioids, or heroin-like chemicals. And, as we all know, unsated desire is far from pleasurable.

So what does dopamine have to do with disappointment? Many researchers now think that, when acting in certain circuits, dopamine connects expectations with actual experience — or, in the jargon of science, it signals “reward prediction error.” And what that means is that dopamine rises or falls with the accuracy of our mental projections, which makes an inaccurate prediction of a reward punishing.

A prediction error is mathematically simple: It’s the difference between what you expect and what you get. Research originally conducted by Cambridge University’s Wolfram Schultz has shown that this correlates with dopamine levels in non-human primates.

A positive prediction error means that you got more than you’d thought likely — a pleasant surprise. A negative prediction error, however, means that the promised reward was either missing or less than expected.

Basically, when an experience is better than you thought it would be, you remember this fact — and that makes your expectations for the next time higher, meaning they are going to be harder to exceed.

“Disappointment would be a negative prediction error,” says Schultz, adding that this describes the human psychology of the experience, rather than what he sees in his work, which involves animals.

But monkeys, too, can be let down: Their dopamine levels fall when a light or sound that typically signals a tasty treat or shot of cocaine isn’t followed by the expected reward, and it’s clear from their behavior, at least, that this isn’t pleasant for them.

When there is a negative prediction error — i.e., when your plans go awry or that delicious-looking cake turns out to be bland and dry — dopamine levels fall. When you get exactly what you expect — no better or worse — they stay stable.

Only when there is an unanticipated delight do you get a big boost.

Unfortunately, this system creates what researchers call the “hedonic treadmill,” which means that unless rewards are constantly getting bigger and more exciting, even the best experiences pale over time when repeated.

What was once terrifyingly thrilling eventually becomes routine: If this didn’t happen, our brains couldn’t remain sensitive to novelty — and that’s essential for learning and, therefore, for survival.

Those of us who have addiction are all-too-painfully familiar with this phenomenon, which is known as tolerance or habituation. It means that no matter how much we use, it rarely feels like enough. And, this, too, involves dopamine’s role in prediction.

Basically, when an experience is better than you thought it would be, you remember this fact — and that makes your expectations for the next time higher, meaning they are going to be harder to exceed.

So, even if that beach is exactly as beautiful as it was the first time you vacationed there, unless it has somehow gotten even more great, you typically won’t experience the splendor as intensely. Similarly, that rock or shot.

“The thing with the dopamine neurons is [that] you’re not only getting a high when your reward is better than predicted, but your prediction is also running away,” Schultz says. That means that the same reward, compared to a larger prediction, will give a negative prediction error, making it at least a little disappointing. (This is also why expecting perfection or that some event will be “the best day of your life” is a self-undermining recipe for dissatisfaction.)

During addiction, of course, drugs themselves affect dopamine levels — but this doesn’t free us from the hedonic treadmill. In fact, drugs like cocaine and amphetamine that directly increase dopamine levels make it even more vicious.

By artificially raising dopamine levels, stimulants increase the brain’s prediction that the drugs will be good the next time. And this means that — unless you keep upping the dose — the high will almost never be as fabulous as that “first time” so many people recall so fondly. And even if you can somehow afford ever-increasing doses, this tends to escalate craving, while the level of satiation — how much you like the drug when you get it — remains the same.

In other words, you want the drug more and more, even though, because of the negative consequences of addiction, you may actually like it less. If a drug could actually intensify satisfaction itself over time — rather than simply escalating craving — you’d get the strange phenomenon of having to take less and less to achieve the same high, which would be delightful for drug users but not so much for dealers.

Sadly, however, the only effects that seem to increase with ongoing heavy drug use are negative ones like paranoia and craving. Even with opioids, which act directly at the receptors that drive satiation, tolerance still develops.

All of this means that Buddha was right: Suffering is caused by desire and, unless you reduce desire, suffering is inevitable. If you don’t expect too much, you won’t be disappointed; low expectations will lower negative prediction errors.

On the other hand, for me at least, expectations and predictions are motivating, and themselves a source of joy: Being without desire can also mean being without the ability to feel pleasure, as in the anhedonia of depression.

There is, however, a spiritual or simply human antidote to disappointment — one popularized by Buddhism, by other faiths and philosophies, and indeed by 12-step programs. And that is gratitude.

If you are grateful for what you have — allowing yourself to feel satisfaction for the present no matter what you desire or predict — this can counteract disappointment.

In my life, I’ve often had to lower my expectations, even though, as a basically optimistic person, this cuts against my grain. Perhaps because of my typically sunny temperament, when I try to avoid expecting too much, I rarely succeed entirely: My dopamine is going to make some sort of prediction, regardless of what I think on the cognitive level. This has meant that I often find myself disappointed by expectations I didn’t know I had.

When I cultivate gratitude, however — and critically, when I’m not depressed, which can obliterate my normal emotions if I don’t take my antidepressants and keep up my social safety net and do things like exercise — almost anything can become delightful.

I know that my addiction could have killed me, that all of the wonderful things I have in my recovery now are not just because I’ve worked hard and tried to do the right thing, but because I’ve had luck and help and, frankly, privilege.

Keeping that in mind makes simple pleasures greater than expected: All of what I have and experience now is a bonus; in spiritual terms, grace.

The dopamine dip of disappointment will always get you sometimes — but we are also much more than that.

This story originally appeared in The Influence, a Pacific Standard partner site that covers the spectrum of human relationships with drugs. Follow The Influence on Facebook and on Twitter.