Scientists in Australia have received a AUS$2 million ($1.4 million; £940,000) federal government grant to investigate the potential of ketamine to treat depression. Researchers at the Black Dog Institute in Sydney plan to begin recruiting for the trial in March, and will enroll 200 participants who have so far not responded to existing medications for the condition.
While ketamine is known to many as a party drug, it has actually been used in both human and veterinary medicine for many years, predominantly as an anesthetic. Previous small-scale clinical trials have shown that single doses of ketamine can have a positive effect on mood, although there is currently very limited data regarding its long-term impact. “Researchers have seen some amazing responses in small proof-of-concept studies using just one dose of ketamine,” lead researcher Professor Colleen Loo told IFLScience. “But if you look at the number of proper randomized trials, there are only a handful, involving less than 200 people between them”.
Furthermore, while the results of these single-dose studies may be encouraging, Loo insists that the positive mood effects don’t last, and that the impact of multiple doses of ketamine over a sustained period have so far never been tested. The upcoming study will therefore see participants given eight treatments over four weeks, with patients being carefully monitored for several weeks afterwards.
Researchers will be collecting data on a wide range of factors, including depression, anxiety, suicide scores, and quality of life. They will also be taking blood samples and measuring kidney and bladder function, in order to determine the safety of sustained ketamine use – abuse of this drug has been associated with dysfunction of both of these organs.
While many people may think of ketamine as a “downer” drug, Loo explains that the positive mood effects of the drug actually occur once its immediate acute effects have long since passed. “We’ve been running trials with ketamine for three-and-a-half years, and while patients do feel a little groggy immediately after taking it, a day later the mood effects kick in.”
According to Loo, this is caused by a range of neurological changes that occur around 24 hours after ingesting ketamine, such as neuronal regrowth and the generation of new connections between brain cells, or synapses. “This is exciting because all of these effects are the exact opposite to the effects of depression,” she explains. For instance, previous studies have shown that depression can cause a decrease in the number of synapses in parts of the brain.
Prolonged elevation of patients’ moods has previously been observed using a range of other psychoactive drugs, such as MDMA, with some scientists labeling this phenomenon the “psychedelic afterglow.” However, in spite of this encouraging effect, research into the use of such substances has faced a great deal of social and legal opposition, making it difficult to obtain permission and funding for clinical trials. “We’re working in quite a difficult environment,” insists Loo. “This is actually the fourth time that we’ve applied for funding, so we’re delighted to have finally got it.”