Tiny Molecule Can Help Treat Major Depression: Researchers

Researchers say that a tiny molecule - miR-1202 - could be used as a biological marker for major depression. The molecule could also help scientists design better therapeutics to fight depression.

The molecule - miR-1202 - is found only in humans and some primates. People suffering from major depression tend to have low levels of this molecule, according to researchers at te McGill University and the Douglas Institute.

Depression affects around one in ten people in the U.S. Estimates by National Alliance on Mental Health suggest that some 25 million people in the U.S. will suffer from major depression this year. 

The present study could help researchers develop better diagnostic methods and treatment strategies for the depression in people who aren't responding to standard care for the condition.

For the study researchers used brain samples from the Douglas Bell-Canada Brain Bank. The team compared tissue samples from depressed individuals with that of healthy individuals. "We identified this molecule, a microRNA known as miR-1202, only found in humans and primates and discovered that it regulates an important receptor of the neurotransmitter glutamate," said Dr. Gustavo Turecki, a psychiatrist at the Douglas, according to a news release.

Glutamate is an important regulatory protein and is associated with several neural pathways. An imbalance in the levels of the protein is known to lead to depression and obsessive-compulsive disorder (OCD), Medical Daily reported.

The team conducted several experiments and found that anti-depressants altered the levels of this molecule.

"In our clinical trials with living depressed individuals treated with citalopram, a commonly prescribed antidepressant, we found lower levels in depressed individuals compared to the non-depressed individuals before treatment," said Turecki. "Clearly, microRNA miR-1202 increased as the treatment worked and individuals no longer felt depressed."

Anti-depressants are one of the most prescribed drugs in the U.S. The study partly explains why some people respond to common drugs for depression while others don't. The study could also help researchers develop better drugs for depression.

The study is published in the journal Nature Medicine.