Matthew Perry cause of death Ketamine - here's how the drug changes the brain

The death of Matthew Perry has been ruled an accident from the “acute effects of ketamine”, the County of Los Angeles Department of Medical Examiner confirmed, after he was found “unresponsive in the pool at his residence” on 28 October before he was pronounced dead at the age of 54. A post-mortem examination concluded Perry's death also involved contributing factors included “drowning, coronary artery disease and the effects of buprenorphine” – which is used to treat opioid use disorder.

But how does Ketamine change the brain? A recent study by Columbia University, published in the scientific journal Cell Reports, found that repeated use of ketamine over an extended period leads to widespread structural changes in the brain’s dopamine system. Ketamine is a multifunctional drug with clinical applications as an anaesthetic, pain management medication, and a fast-acting antidepressant. However, it is also recreationally abused for its dissociative effects affecting dopamine - a neurotransmitter that affects things like how we feel pleasure and how we think.

To discover this, the biologists and biomedical engineers at Columbia used high-resolution imaging to map the brains of mice given doses of ketamine over one, five and 10 days. The structural changes were observed on the dopamine system after 10 days. Talking to VICE, Raju Tomer, the senior author of the study, revealed that the researchers found a broad impact which was different in different parts of the brain.

In some [parts of the] brain, there was a positive impact, and it led to an increase in the number of dopamine neurons. In the hypothalamus area, there was an increase in the number of dopamine neurons, whereas in some regions like the midbrain – especially the dorsal raphe, which is involved in things like social isolation and social behaviour there was a decrease in the number of dopamine neurons. 

He added that they found an increase in connections to the prefrontal cortex, which is involved in higher-order cognitive functions. There was a decrease in the sensory part of the brain, the sensory cortex, including visual and auditory.

He explained: "The study’s clearly showing that – at least in mice – when used over time and at higher doses, it's causing these very significant changes in the brain. They’re also significant [changes] from a functional perspective. It's detaching your senses from your cognitive capabilities."