Is Happiness a Peptide called Hypocretin?

Medical Reviewer

It's a sobering thought that the effectiveness of antidepressants is still being debated. Sometimes the weight of evidence appears to come down on the side of antidepressants and sometimes not. Various studies seem to point to the clinical effectiveness of antidepressants in only the most severe cases of depression. According to UCLA professor of psychiatry Jerome Siegel, the use of antidepressants are not based on evidence of a deficiency, or for that matter an excess, of any neurotransmitter and this had lead many studies to question whether antidepressants are any more effective than placebos.

While the debate rumbles on the number of people experiencing symptoms of depression increases and the need for answers is ever more pressing. Seigel and his team believe they may have found a potential new treatment in the fight against depression. They discovered that when people are happy they release a specific peptide, a neurotransmitter called hypocretin. This same peptide decreases during times of sadness. The team was also able to measure the release of another peptide called melanin concentrating hormone that increases greatly during sleep.

The combination of findings is interesting for at least two reasons. Seigel notes that people who suffer with narcolepsy, a disorder characterized by uncontrollable periods of sleep, have 95 percent fewer hypocretin cells than people without the disorder. Not only does this offer a possible biological explanation for the cause of narcolepsy but also perhaps the sleepiness so often associated with depression.

The findings were obtained from eight patients being treated for intractable epilepsy at the Ronald Regan UCLA Medical Center. Patients were implanted with brain electrodes in order to identify focal areas within the brain that trigger seizures. Patients were recorded during everyday routines such as eating, talking, watching television and sleeping.

Professor Seigel suggests that boosting the level of hypocretin could elevate mood and alertness and may well provide the foundation for treating depression by targeting measurable changes or abnormalities in brain chemistry. Seigel notes that some drug companies are already exploring the use of so-called hypocretin antagonists in the development of sleeping pills.


University of California - Los Angeles (2013, March 7). Is this peptide a key to happiness? Findings suggests possible new treatment for depression, other disorders. ScienceDaily. Retrieved March 14, 2013, from ­ /releases/2013/03/130307145720.htm