The Overlooked Symptom That Makes Depression So Hard to Treat

WebMD

29-07-2025

July 28, 2025 – It's one of the first symptoms when diagnosing depression: "Loss of interest or pleasure in activities once enjoyed."
Psychologists call it anhedonia, from Greek roots meaning "without pleasure." (It's the opposite of "hedonism," the pursuit of pleasure.)
You may not be familiar with the term (unless you're a big Annie Hall fan – it was the film's original title), but anhedonia is one of two core features, alongside persistent low mood, in depression's long list of symptoms. It's also one of the hardest to treat, and a significant risk factor for battling lifelong depression.
But new research offers encouragement. Scientists are uncovering anhedonia's little-understood causes, opening doors to new treatments like exploring the meaning of life during therapy or identifying brain biomarkers that predict the most effective medications.
Though the symptom is notoriously stubborn, really tuning into your anhedonia can set you on a path to overcoming it, experts say – and lessen the chances that depression will recur.
"We see it all the time in our clinics, where patients are significantly struggling with the lack of motivation and the lack of experiencing pleasurable activities that they used to enjoy," said Majd Al-Soleiti, MD, a resident psychiatrist at the Mayo Clinic in Rochester, Minnesota, and author of a recent anhedonia study review. "So it's a clinical problem, but also we have gained a lot of knowledge in terms of how it may explain so many problems that we have that go beyond depression."
Cracking the Mystery of Anhedonia
Anhedonia shows up in a broad range of health conditions, including substance use disorders, eating disorders, and neurodegenerative diseases like Alzheimer's and Parkinson's. An estimated 35% of people with epilepsy have anhedonia, plus nearly 20% of people who've had strokes, and 25% of those with chronic pain. Among depression patients, up to 70% have anhedonia.
We've all learned to tolerate a lack of pleasure in certain situations, like traffic jams and toddler tantrums. Anhedonia is different – it persists, and it's the result of the brain's reward processing circuitry malfunctioning.
"People need to take anhedonia very seriously because it can have very negative consequences," including a heightened risk of suicide, said Diego Pizzagalli, PhD, an anhedonia expert and founding director of the Noel Drury, MD, Institute for Translational Depression Discoveries at the University of California, Irvine.
Neuroimaging has refined the understanding of anhedonia – in particular, that there are two main subtypes: consummatory and anticipatory.
Knowing the type of anhedonia can help identify the most effective treatment.
Before and After: Anticipation and Consumption
Most of us get excited knowing that something good is about to happen – you're going to eat your favorite meal or go on a trip. This is the anticipatory reward processing effect. When anticipatory anhedonia sets in, the pleasure and excitement aren't there. Consummatory anhedonia, by contrast, refers to a lack of pleasure during activities or interests that were once enjoyable.
In both cases, imaging shows that the brain no longer responds as though it is expecting or experiencing a reward.
"When someone is depressed, they will often stop meeting up with friends as often, or they'll stop doing the hobbies that they usually enjoy because those kinds of things just don't feel as enjoyable or they don't feel as interesting as they used to," said Jennifer N. Bress, PhD, a psychologist at Weill Cornell Medicine in New York City who researchers brain activity linked to depression and treatment response.
Bress's research shows that people with anhedonia have differences "on a neural level" – meaning the symptom is linked to changes in the way neurons (brain cells) communicate using electrical and chemical signals.
"The brain's reactivity to rewards also decreases," said Bress.
A classic experiment demonstrates this. It's a guessing game where people being researched can win 50 cents for each correct answer, or lose 25 cents if they're wrong.
"People have less electrical activity in their brain in response to winning money when they're depressed versus when they're not," Bress said. And yes, they really give people 50 cents – or take a quarter away. "There's something about knowing that this is real and that they will actually win something that's important to getting a robust response."
What that means outside the lab: When you're working to overcome anhedonia, it's important that the rewards you anticipate or experience be real – because your brain responds more strongly when stakes are tangible.
Treatments That Help
One of the most effective treatments for anhedonia – whether anticipatory or consummatory – is a therapy called "behavioral activation," said Pizzagalli.
Behavioral activation takes a step-by-step approach to help patients get back to activities they once enjoyed. This includes scheduling each step leading up to the activity, such as deciding who will join you, and organizing the smallest logistics in advance. Therapists help clients overcome barriers along the way.
New potential therapy approaches are emerging. One is "positive affect" treatment, where people work to focus more on positive emotions with the added goal of feeling fewer negative emotions. The idea is that increasing positive emotions can heighten reward sensitivity – helping the brain break out of its anhedonic cycles. Other research suggests that therapies focused on identity, purpose, and social connection may help by boosting a person's "meaning in life," which may in turn reduce anhedonia.
Here's the theory behind why these therapies work: With anhedonia, brain connections in reward processing weaken when people disengage from their usual activities and interests.
"You end up in this sort of feedback loop where you become even more depressed and feel even less like doing things," Bress said, "so you get even fewer opportunities for rewards, which in turn leads to becoming even more depressed."
Ultimately, the brain becomes less responsive to rewards.
Behavioral activation gives patients "more opportunities to be exposed to these rewarding outcomes," she said, which "may help to strengthen some of these connections in the brain that help people respond in a healthy way to rewarding experiences."
Antidepressants tend not to work as well for anhedonia, particularly for the most severe cases, research shows. Still, there is hope for the future, as researchers develop a more detailed understanding of what is happening in the brain. Pizzagalli's team is studying brain biomarkers that may help predict which medications will work well for a particular person, laying the groundwork for a personalized approach. But for now, drugmakers have yet to develop a medication to specifically treat anhedonia, he said.
One promising contender is ketamine, which has been shown to rapidly reduce anhedonia and likely impacts the brain's functional connections. Al-Soleiti's recent paper also mentioned transcranial magnetic stimulation (TMS) and electroconvulsive therapy (ECT) as being notably effective in treating anticipatory anhedonia.
Also helpful is simply improving diet and lifestyle, since these changes can reduce inflammation and stress, which both are linked to anhedonia, Pizzagalli said.
Weighing Your Options
While many unanswered questions remain in the science of anhedonia, researchers do know that the two types affect separate areas of the brain. While both anticipatory and consummatory anhedonia have been linked to depression, the association with anticipatory anhedonia has been demonstrated more consistently.
"You could have no problem actually enjoying things that you might like – say you watch a funny video and really enjoy it," Bress said. "But you may have a lot of trouble with the anticipatory piece or the motivational piece. You might notice it's really hard to actually get yourself to turn on the video, or it might be that you really enjoy seeing your friends once you go out, but it might be hard to push yourself to actually make that plan and go meet up with them at the coffee shop."
For therapy approaches, treatment usually involves weekly sessions for anywhere from two to six months. Some of Bress's clients have shown improvement within just a couple of weeks. Even if past treatments haven't worked, Pizzagalli urged people not to give up. Most therapists are trained in more than one type of therapy, so if you are considering therapy, ask if they use behavioral activation therapy or another approach specific to anhedonia.