New Research Opens Door For Treatment of Depression For The Left-Handed

The results of a new study may have scientists reexamining how they treat individuals suffering from major depressive disorder.

Motivation, the underlying drive that propels us into action, has always been regarded as a key component of emotion. Experts have upheld that motivation is controlled by the left brain, while avoidance motivation is predominately regulated by the right brain.

Researchers, Geoffrey Brookshire and Daniel Casasanto questioned the validity of that theory after their own research caused them to cast doubt.

For their study, Brookshire and Casasanto measured participants’ brain waves from both the left and right sides while subjects were in a resting state. Afterwards, participants filled out an assessment that was used to determine their level of approach motivation.

Approach motivation is telling about an individual’s personality because it shows how comfortable one is with new people and circumstances.

Brookshire and Casasanto found that for participants who were right-hand dominant, approach motivation was associated with greater activity in the left side of the brain. The opposite was true for the left-handers. It appears that for whatever side is hand dominant, the opposite side of the brain activates when stimulated for approach motivation.

Researchers had postulated that this might be the case because they had noted that individuals seemed to prefer one hand over another to signify approach and avoidance motivation cues. They believe the reason for the connection to be related to circuits in the brain. The paths in the brain that control motivation may be connected to paths that direct hand motions.

The authors are quick to advise that the study does not prove cause but only an association between motivation and motor functioning. However, the study may have implications in the treatment of certain types of depression.

One method of treatment for severe depression is administering electrical stimulation to the left side of the brain, the side of the brain traditionally believed to control approach motivation. Researchers believe that the results of the study may lead to alternate treatments for left-handed individuals.

To find out more, check out the results of Brookshire and Casasanto’s in PLoS One journal.