"Australian researchers have completed the worlds first randomised control trial RCT assessing the efficacy and safety of ketamine as a treatment for depression in elderly patients.  The results published in the latest American Journal of Geriatric Psychiatry provide preliminary evidence suggesting ketamines effectiveness as an antidepressant when delivered in repeated intravenous doses.  Led by a team of researchers from UNSW Sydney and Black Dog Institute the trial tested different doses of ketamine amongst  older age participants aged over  years who had treatmentresistant depression administered at Wesley Hospital. These findings take us a big step forward as we begin to fully understand the potential and limitations of ketamines antidepressant qualities said lead author UNSW Professor Colleen Loo who is based at Black Dog Institute. Not only was ketamine welltolerated by participants with none experiencing severe or problematic side effects but giving the treatment by a simple subcutaneous injection a small injection under the skin was also shown to be an acceptable method for administering the drug in a safe and effective way. Participants received increasing doses of ketamine over a period of five weeks with doses optimised for each individual participant using a new dosetitration approach developed by Professor Loos Sydney research team and collaborators. As part of the doubleblind placebocontrolled trial an active control treatment which causes sedation similar to ketamine was used to substitute for one of the treatment sessions. Researchers monitored for mood and other sideeffects after each treatment session. Following the RCT participants also received  ketamine treatments in an openlabel phase to investigate the effectiveness of multiple doses of ketamine. By the sixmonth follow up  percent of participants  of  who completed the RCT had remitted with five remitting at amounts below the commonlyused dose of . mgkg. Repeated treatments also resulted in a higher likelihood of remission or a longer time to relapse with an overall response and remission rate of . percent for the patients receiving ketamine treatment.  Elderly patients with severe depression face additional barriers when seeking treatment for the condition. Many medications may cause more side effects or have lower efficacy as the brain ages said coauthor Dr Duncan George from UNSW Sydney. Older people are also more likely to have comorbidities like neurodegenerative disorders and chronic pain which can cause further complications due to ketamines reported side effects. Our results indicate a dosetitration method may be particularly useful for older patients as the best dose was selected for each individual person to maximise ketamines benefits while minimising its adverse side effects. Previous studies into ketamine treatments for older people with depression  which are limited to just five case reports  show mixed success with findings limited by small sample sizes.  More broadly little is known about ketamines potential side effects at different doses which include cognitive and dissociative effects elevated blood pressure and heart rate liver inflammation and urinary problems. These results are a promising early piece of the puzzle but the risks of ketamine use are still not wholly understood. Future studies with greater sample sizes are needed to formally assess ketamines side effects such as its impact on liver function Professor Loo added.  The study was a collaboration between UNSW Sydney Black Dog Institute Royal North Shore Hospital The Wesley Hospital Kogarah the Dementia Collaborative Research Centre and the University of Otago. Professor Loo will build on these promising results as part of her current work directing the worlds largest trial of ketamine to treat depression which is now recruiting participants. For more information about the study contact ket.studyunsw.edu.au mailtoket.studyunsw.edu.au or call   ."