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Ketamine, an anesthetic and street drug known as “Special K” has garnered a lot of attention for its ability, in some, to relieve the symptoms of very severe depression in a matter of minutes.
A recent study has demonstrated how it might work, but before you go signing up for a clinical trial (and there are currently many going on in the US), it’s important to understand the downsides to the drug. One major problem is that the effects wear off, usually within 10 days, leaving you just as depressed as before. It can cause urinary incontinence, bladder problems, addiction, and, with chronic use, it can worsen mental health problems, causing more depression, anxiety, and panic attacks.
Ketamine seems to have a remarkable, short term ability to heal the synapses injured by chronic stress. However, anything that acts that quickly and successfully usually has a long-term cost. All powerfully addictive drugs work on our own natural receptors and neurons. Cocaine, for example, causes immediate racing euphoria by inhibiting the natural neurotransmitter dopamine from being recycled, leaving bunches of dopamine in the synaptic cleft. In the very short term, you feel great. In the long term, you tax the system by driving the neurotransmitter system far out of balance in an aggressive way.
Nicotine has a similar effect on the alpha-7 nicotinic receptor. It activates it in a pleasing way, but unfortunately desensitizes the receptor so much that only nicotine will keep it firing. A nutrient found in foods such as egg yolks called choline activates the same receptor, but without desensitizing it. Long term, regular ingestion of choline keeps the receptor functional and happy, helping with certain brain tasks. Long term, regular use of nicotine activates the receptor but forces you to take more nicotine to keep the receptor working, leaving you foggy-headed and less sharp if you go without cigarettes.
So is there a less dramatic, “natural” version of ketamine, something we can safely ingest every day, but might be a little depleted in our modern diets? Nothing taken in physiologic amounts would reverse depression in half an hour like ketamine, but could another chemical we find in food and mineral water help with resilience to stress, synaptic repair, and make us more resistant to depression and anxiety symptoms?
Sure—that chemical is the mineral magnesium. Magnesium, like ketamine, acts as an antagonist to the NMDA receptor, which means it is a counter to glutamate, the major excitatory neurotransmitter in the brain. The exact mechanisms are complex, but both ketamine and magnesium seem to help glutamate do its job, activating the receptor without damaging it from too much activation, which, chronically, leads to excitotoxicity, synaptic degradation, inflammation, and even cell death.
One of the exciting things about ketamine is that it works in some people with severe treatment-resistant depression who have failed the traditional therapies. Treatment-resistant individuals tend to have lower intracellular magnesium levels than normal (1). Ketamine and magnesium may also work synergistically, complementing each other. Ketamine leads to an increase of intracellular magnesium, and ketamine will reverse the normally seen magnesium decreases after brain trauma (2). There is some evidence also that more standard antidepressant medications, such as imipramine, work in part by reversing the magnesium-depleting effects of chronic stress, suggesting that adding magnesium supplementation to standard antidepressant regimens might help the medications work better (at least in rodents) (3).
It’s great to see an interesting compound like ketamine be taken seriously and thoroughly studied for its action in serious, resistant depression. Ultimately its usefulness may be limited to hospitalized patients who can be closely monitored for the side effects, and who also may benefit the most from the quick mechanism of action, while the longer term risks may be outweighed by the short term benefit in such a critical, serious situation. I would love to see a much safer compound, the mineral magnesium, be studied as an adjunct treatment.
In the meantime, magnesium supplementation is generally safe for most folks with normal kidney function. Many folks eating a normal Western Diet have a low intake of the mineral (4). Those with bowel obstructions, very slow heart rate, or dangerously low blood pressure should not take it. Magnesium can interfere with the absorption of certain medicines (digoxin, nitrofurantoin, bisphosphanates, and some anti-malaria drugs).
Here are some excellent food sources of magnesium (though remember that both nuts and grains have phytates, which bind minerals, so the magnesium you absorb may not be quite as much as the magnesium you ingest.) Magnesium is also available in many mineral waters.
For more information about magnesium and the brain, please read my article here: Magnesium the Original Chill Pill. A nice paper from last year details the ketamine-magnesium connection if you have journal access (thanks to Drew Ramsey for pointing the paper out to me).
Copyright Emily Deans MD
