Could a drug that is also used as a horse tranquilizer cure depression? Yes apparently, according to scientists.

The Daily Mail reports that doctors at the Ben Taub General Hospital in Houston, Texas, are currently testing the effects of the prescription drug Ketamine on patients who are suffering from severe depression.

The Class C drug, which is illegal to possess or sell, can reportedly cause a loss of feeling in the body and gives users a feeling of being 'separated' from their bodies. The drug also has powerful hallucinogenic affects if too much is taken.

However, scientists have given reports that Ketamine could also make the symptoms of depression ‘vanish’ almost instantly. Mental health researchers are trying to discover if Ketamine can be used to bridge the gap between when proper medication is started and when it begins to have an effect on the patient.

In most cases common medication for depression takes at least three weeks to kick in. During these three weeks patients have a higher chance of experiencing suicidal thoughts. If Ketamine was used in the meantime, suicidal feelings could be prevented and lives could potentially be saved.

Scientists are giving trial patients one infusion of either Ketamine or a placebo and comparing the results.

“It was almost immediate, the sense of calmness and relaxation. No more fogginess. No more heaviness. I feel like I’m a clean slate right now,” said one trial patient who believes she is on Ketamine rather than a placebo.

Researchers have said that the consistent positive patient reactions have made it hard to prevent doctors from working out who has been given the drug and who has been given the placebo.

If the trial continues to have successful results, researchers will give the drug to patients three times a week to test the long-term effects. Scientists hope that patients in the second trial will experience a radical mood boost that will last for a few months.