London, Dec 26 : Ketamine therapy has a swift short-term effect on reducing symptoms of depression and suicidal thoughts, new research has found. The findings indicated that the strongest evidence emerged around the use of ketamine to treat both major depression and bipolar depression, with symptoms reducing as swiftly as one to four hours after a single treatment. The effect lasted up to two weeks. "Our findings suggest that ketamine may be useful in providing rapid relief from depression and suicidal thoughts, creating a window of opportunity for further therapeutic interventions to be effective," said lead author Merve Mollaahmetoglu from the UK's University of Exeter. "It is important to note that this review examined ketamine administration in carefully controlled clinical settings where any risks of ketamine can be safely managed," Mollaahmetoglu added. As per the research, published in the British Journal of Psychiatry Open, similarly, single or multiple doses of ketamine resulted in moderate to large reductions in suicidal thoughts. This improvement was seen as early as four hours following ketamine treatment and lasted on average three days, and up to a week, the research said. For other psychiatric disorders, including anxiety disorders, post-traumatic stress disorders and obsessive-compulsive disorders, there is early evidence to suggest the potential benefit of ketamine treatment, it added. Moreover, for individuals with substance use disorders, ketamine treatment led to short-term reductions in craving, consumption and withdrawal symptoms. For the study, the team included 33 systematic reviews, 29 randomised control trials, and 21 observational studies. "We're finding that ketamine may have promising benefits for conditions that are notoriously hard to treat in the clinic. We now need bigger and better-designed trials to test these benefits," said co-author Celia Morgan from the varsity. /IANS