Featured Research

from universities, journals, and other organizations

Worth The Effort? Not If You're Depressed

Date:
August 16, 2009
Source:
Vanderbilt University
Summary:
New research indicates that decreased cravings for pleasure may be at the root of a core symptom of major depressive disorder. The research is in contrast to the long-held notion that those suffering from depression lack the ability to enjoy rewards, rather than the desire to seek them.

Individuals suffering from anhedonia, a key symptom of depression, are less likely to pursue rewards if effort is required to obtain the reward.
Credit: Michael Treadway, Vanderbilt University

New research indicates that decreased cravings for pleasure may be at the root of a core symptom of major depressive disorder. The research is in contrast to the long-held notion that those suffering from depression lack the ability to enjoy rewards, rather than the desire to seek them.

The research, led by Vanderbilt psychologists Michael Treadway and David Zald, was published Aug. 12 by the online journal PLoS One.

"This initial study shows that decreased reward processing, which is a core symptom of depression, is specifically related to a reduced willingness to work for a reward," Treadway, a graduate student in psychology, said.

Decreased motivation to seek and experience pleasurable experiences, known as anhedonia, is a primary symptom of major depressive disorder. Anhedonia is less responsive to many antidepressants and often persists after other symptoms of depression subside. However, understanding the different components of anhedonia - the desire to obtain something pleasurable versus experiencing pleasure - has been difficult for researchers to determine in humans.

"In the last decade and a half, animal models have found that the neurotransmitter dopamine, long known to be involved in reward processing, is involved in craving or motivation, but not necessarily enjoyment," Treadway said. "To date, research into reward processing in individuals with anhedonia has focused on enjoyment of rewards, rather than assessing the drive to work for them. We think this task is one of the first to do that."

Treadway and his colleagues devised the Effort-Expenditure for Rewards Task, or EEfRT, to explore the role of reduced desire and motivation in individuals reporting symptoms of anhedonia. EEfRT involved having individuals play a simple video game that gave them a chance to choose between two different tasks, one hard, one difficult, to obtain monetary rewards. Participants were eligible but not guaranteed to receive money each time they completed a task successfully.

The "hard" task required pressing a button 100 times within 21 seconds using one's non-dominant little finger and carried a potentially higher reward than the easy task, which required pressing a button 30 times in seven seconds using one's dominant index finger. The subjects were told at the beginning of each trial whether they had a high, medium or low probability of winning a prize if they successfully completed the trial. The participants could choose which trials they completed and were given 20 minutes to perform as many tasks as possible.

The researchers found that subjects who reported symptoms consistent with anhedonia where less willing to make choices requiring greater effort in exchange for greater reward, particularly when the rewards were uncertain.

"Consistent with our hypotheses, we found that individuals with self-reported anhedonia made fewer hard-task choices," the authors wrote. "These findings are consistent with theoretical models linking anhedonia to decreased (dopamine levels)."

"By addressing the motivational dimension of anhedonia, our findings suggest a plausible theoretical connection between dopamine deficiency and reward processing in depression, which may eventually help us better understand how anhedonia responds to treatment," Treadway said.

Zald is an associate professor of psychology. Treadway and Zald's co-authors were Joshua W. Buckholtz, a Vanderbilt doctoral student in neuroscience, Ashley Schwartzmann, research analyst, and Warren Lambert, a research associate in the Department of Special Education and at the Vanderbilt Kennedy Center for Research on Human Development.

Funding from Vanderbilt University and the National Institute on Drug Abuse supported the research.

 


Story Source:

The above story is based on materials provided by Vanderbilt University. Note: Materials may be edited for content and length.


Cite This Page:

Vanderbilt University. "Worth The Effort? Not If You're Depressed." ScienceDaily. ScienceDaily, 16 August 2009. <www.sciencedaily.com/releases/2009/08/090812181437.htm>.
Vanderbilt University. (2009, August 16). Worth The Effort? Not If You're Depressed. ScienceDaily. Retrieved April 19, 2014 from www.sciencedaily.com/releases/2009/08/090812181437.htm
Vanderbilt University. "Worth The Effort? Not If You're Depressed." ScienceDaily. www.sciencedaily.com/releases/2009/08/090812181437.htm (accessed April 19, 2014).

Share This



More Mind & Brain News

Saturday, April 19, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Study On Artists' Brain Shows They're 'Structurally Unique'

Study On Artists' Brain Shows They're 'Structurally Unique'

Newsy (Apr. 17, 2014) — The brains of artists aren't really left-brain or right-brain, but rather have extra neural matter in visual and motor control areas. Video provided by Newsy
Powered by NewsLook.com
Is Apathy A Sign Of A Shrinking Brain?

Is Apathy A Sign Of A Shrinking Brain?

Newsy (Apr. 17, 2014) — A recent study links apathetic feelings to a smaller brain. Researchers say the results indicate a need for apathy screening for at-risk seniors. Video provided by Newsy
Powered by NewsLook.com
Are School Dress Codes Too Strict?

Are School Dress Codes Too Strict?

AP (Apr. 16, 2014) — Pushing the limits on style and self-expression is a rite of passage for teens and even younger kids. How far should schools go with their dress codes? The courts have sided with schools in an era when school safety is paramount. (April 16) Video provided by AP
Powered by NewsLook.com
Could Even Casual Marijuana Use Alter Your Brain?

Could Even Casual Marijuana Use Alter Your Brain?

Newsy (Apr. 16, 2014) — A new study conducted by researchers at Northwestern and Harvard suggests even casual marijuana use can alter your brain. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins