In an effort that could help improve treating people with depression, researchers claim to have identified a compound called hydroxynorketamine (HNK).

The research showed that the compound HNK can help treat symptoms of depression just as effectively as the psychoactive drug ketamine without the unwanted side effects associated with it.

Irving Wainer, a senior investigator from the National Institute on Aging in the US, said that the clinical use of ketamine therapy for depression is limited because the drug is administered intravenously and may produce adverse effects such as hallucinations and sedation to the point of anaesthesia.

"We found that the HNK compound counters depressive symptoms but it does not cause sedation as in the case of ketamine. It makes HNK an attractive alternative as an anti-depressant in humans," Wainer noted.

To come to this conclusion, researchers used a rat model, where rats were administered intravenous doses of ketamine, HNK and another compound produced by ketamine metabolism known as norketamine.

They found that the compound HNK, like ketamine, not only produced potent and rapid anti-depressant effects but also stimulated neuro-regenerative pathways and initiated the re-growth of neurons in rats' brains.

Researchers also found that HNK reduced the production of D-serine - a chemical found in the body whose over-production is associated with neuro-degenerative disorders such as Alzheimer's and Parkinson's diseases.

The study, published in the Journal of Anaesthesiology, states that the use of HNK can also serve as a future therapeutic approach to treat neuro-degenerative disorders such as Alzheimer's and Parkinson's diseases.