The experience of depression differs depending on who you are. Unfortunately, so does the effectiveness of the treatment. While antidepressants work for some, others are driven to use experimental options, such as ketamine-based nasal spray, to alleviate persistent symptoms. Others find no relief at all.
Knowing who can benefit the most from any type of depression treatment before digging through the medicine cabinet can provide relief sooner. In a new study, scientists show that people with certain brain signals more often benefit from one basic, effective treatment: exercise.
In a study of 66 adults with major depression, scientists found eight weeks of moderate aerobic exercise was enough to reduce symptoms by about 55 percent. Meanwhile, light intensity reduced stretching symptoms by 31 percent over the same period of time.
Important found the scientists too a biomarker that may predict why exercise seems to work for these patients. These individuals were most likely to have fewer symptoms of depression to begin with and greater levels of reward processing in the brain.
This study tells us two things. First, it adds to a growing body of evidence suggesting that aerobic exercise, even easy exercise, can help reduce symptoms of depression. It also suggests that people join greater levels of reward processing (but even worse symptoms) can benefit even more from exercise.
The study was published Monday Psychological medicine.
Brandon Alderman, lead author of the study and an associate professor at Rutgers University, explains Inverse that, typically, people with lower reward processing see greater improvements after traditional treatments, such as therapy or drugs.
In fact, several recent studies have shown that depressed patients with lower, as opposed to greater reward processing as found in our study, experienced greater symptom improvement after treatment with cognitive behavioral therapy and SSRIs[traditionalantidepressantdrugs’seithy[traditionalanti-depressantdrugs’hes[tradisjoneleanty-depressivemedisinen”seithy[traditionalanti-depressantdrugs”hesays
This study, he continues, suggests that people who benefit most from exercise or treatment are the same ones who predict less benefit from traditional treatments – those with greater levels of reward processing.
Measurement of reward processing – Dysfunctional reward processing is thought to be a central function of depression. In a 2018 study, aldermen found that 100 young adults with more severe symptoms of depression showed less activity in the reward circles when they won money in a guessing game when the experiment went ahead. They had less sensitivity to rewards over time.
In this study, before devising an exercise plan, the team measured how the 66 participants processed rewards. They also had the players play a guessing game where they won money, or lost, by randomly choosing a door, and measured the corresponding activity in their brains with an EEG.
Participants then engaged in eight weeks of light stretching or moderate-intensity exercise – such as 45 minutes of walking or cycling. They worked out three times a week.
At the end of eight weeks, the results suggested exercise had no effect on how people processed rewards. However, those who had high reward processing were 45 percent more likely to respond to exercise treatment. Those who had fewer symptoms at baseline were 18 percent more likely to respond.
Unfortunately, Alderman says it is not possible to predict how one’s reward system will work right now. There is some speculation that we might be able to use a questionnaire to help determine reward processing in the future.
But could reward processing become something that is easily and often determined by an EEC? Perhaps: These findings are only preliminary, the authors of the study cautioned. However, all the tools exist to use reward processing as a biomarker. The EEG measurement used in his study is “already widely used in medical practice,” says Alderman.
“It is easy to imagine that the type of EEC-based measure used in our study could be more widespread,” he says.
Workouts and depression
By improving treatment effectiveness, the study helps to determine how efficacy can serve as a treatment for depression. Moderate aerobic exercise was more effective than light stretching (although people who did light stretching saw a reduction in symptoms).
“Even light walking is beneficial for depression,” says alderman. “Our findings of a greater anti-depressant effect after aerobic exercise in moderate-intensity relative to light stretching suggest that even greater benefits can be derived from more vigorous exercise.”
That said, moderate activity is usually a good starting point. A 2004 report paper on the use of exercise as a treatment for depression suggests starting with lower-intensity exercise activities that you enjoy. This helps in creating a habit that allows you to build from there.
This new paper suggests that sticking with a regimen over time can lead to positive results. The improvements in symptoms of depression were only significant at the end of the eight-week experiment. Alderman and his colleagues suggest that eight weeks may be the “minimum dose” needed to feel the effects of exercise.
Eight weeks may feel like a long time to wait for results – but until the measurement of reward activity becomes seamless, it may be worth a try.
“Exercise has been shown in countless studies to be beneficial for depression, and our data only add to the growing body of evidence,” says Alderman.
Partial Abstract:
Results: Aerobic exercise resulted in a large reduction in depressive symptoms in adults with major depression. There was no effect of aerobic exercise on the RewP or ERN. In the aerobyske oefeningsgroep were persons with a larger RewP[oddsferhâlding(OR)=145)foarôfgeandebehannelingenferhegebaselinedepressivesymptoomgraad(OR=118)mearkânsomtereagearjenopoefeningsbehandelingFoar-behannelingERNpredisearegjinantwurdopbehanneling(OR=74)[oddsratio(OR)=145)andincreasedbaselinedepressivesymptomseverity(OR=118)weremorelikelytorespondtoexercisetreatmentPre-treatmentERNdidnotpredicttreatmentresponse(OR=74)[oddsferhâlding(OR)=145)foarôfgeandebehannelingenferhegebaselinedepressivesymptoomgraad(OR=118)mearkânsomtereagearjenopoefeningsbehandelingFoar-behannelingERNpredisearegjinantwurdopbehanneling(OR=74)[oddsratio(OR)=145)andincreasedbaselinedepressivesymptomseverity(OR=118)weremorelikelytorespondtoexercisetreatmentPre-treatmentERNdidnotpredicttreatmentresponse(OR=74)
Conclusion: Aerobic exercise is effective in reducing depressive symptoms in adults with major depression, especially for those with increased depression symptoms and greater RewP at baseline. Although aerobic exercise does not align with RewP or ERN, there is preliminary support for RewP in predicting who is most likely to respond to exercise as a treatment for depression.
