The Secret to being Happy Lies in a Peptide

According to a new study, happiness may not be in family or friends, rather in a peptide. For the first time, researchers have been able to measure the levels of a certain peptide called hypocretin which is a neurotransmitter.

The study was conducted by researchers from University of California, Los Angeles, who found that hypocretin rose with study participants' happiness and decreased when the subjects were sad.

Also, researchers discovered a peptide that has been associated with sleep called melanin-concentrating hormone.

According to a previous study, people who suffer from narcolepsy (a condition marked with frequent sleeping) have decreased levels of "hypocretin peptides in their cerebral spinal fluid."

"The current findings explain the sleepiness of narcolepsy, as well as the depression that frequently accompanies this disorder. The findings also suggest that hypocretin deficiency may underlie depression from other causes," said Jerome Siegel, a professor of psychiatry and director of the Center for Sleep Research at UCLA's Semel Institute for Neuroscience and Human Behavior, senior author of the present study.

Since narcolepsy is strongly linked with depression, Siegel and colleagues began studying hypocretin's role in depression.

Data for the present study came from the brains of eight people who were being treated at Ronald Reagan UCLA Medical Center for intractable epilepsy. Researchers then measured levels of the peptides hypocretin and MCH using electrodes that were inserted in the brains of the patients. Researchers also used a kind of membrane that's used in dialysis along with a radioimmunoassay procedure to check the levels of the peptides.

Patients were monitored throughout the study and researchers made notes about their moods while they interacted with friends, family members and the hospital staff.

Study results showed that while the levels of hypocretin were highest when the study subjects felt happy and when they were awake, the levels of MCH were highest at sleep and lowest during social interactions.

"These results suggest a previously unappreciated emotional specificity in the activation of arousal and sleep in humans. The findings suggest that abnormalities in the pattern of activation of these systems may contribute to a number of psychiatric disorders," Siegel said in a news release.

The study is published in the journal Nature Communications.