Current Mental Health Treatments Could Be Dangerous for Left-handed Patients
MOUNT VERNON, IOWA — June 19, 2018
According to the study, "Approach motivation in human cerebral cortex," conducted by Daniel Casasanto, associate professor of human development and psychology at Cornell University Treatment for the most common mental health problems could be ineffective or even detrimental to about 50 percent of the population, according to a radical new model of emotion in the brain.
Daniel Casasanto believes that the common suggestions of the scientists that each hemisphere of the brain is responsible for a specific type of emotion is wrong. Since the 1970s, hundreds of studies have been conducted. Based on those studies, psychologists have concluded that emotions linked to approaching and engaging with the world — like happiness, pride and anger — lives in the left side of the brain, while emotions associated with avoidance — like disgust and fear -- are housed in the right.
Basing these studies therapies for the current treatment for recalcitrant anxiety and depression called neural therapy were developed. It involves a mild electrical stimulation or a magnetic stimulation to one side of the brain, to encourage approach-related emotions.
But Casasanto said, that those studies were done almost exclusively on right-handed people and current treatment techniques could be damaging for left-handed patients. Stimulation on the left would decrease life-affirming approach emotions. "If you give left-handers the standard treatment, you're probably going to make them worse," Casasanto said.
"And because many people are neither strongly right- nor left-handed, the stimulation won't make any difference for them, because their approach emotions are distributed across both hemispheres," he said.
"This suggests strong righties should get the normal treatment, but they make up only 50 percent of the population. Strong lefties should get the opposite treatment, and people in the middle shouldn't get the treatment at all."
In his new study, Casasanto suggested: “The location of a person's neural systems for emotion depends on whether they are left-handed, right-handed or somewhere in between.”
According to his theory, the way we perform actions with our hands determines how emotions are organized in our brains. Sword fighters of old would wield their swords in their dominant hand to attack the enemy — an approach action -- and raise their shields with their non-dominant hand to fend off attack — an avoidance action. Consistent with these action habits, results show that approach emotions depend on the hemisphere of the brain that controls the dominant "sword" hand, and avoidance emotions on the hemisphere that controls the non-dominant "shield" hand.
However, Casasanto warned that the results of the research are preliminary and much work still needs to be done to extend these findings to a clinical setting.