{What if} party drugs are the key to long-term space flight?

Party drugs and on-duty astronauts seem like the most irresponsible combination a person could think up. After all, it costs over 1,000 USD to send about 2 lbs (1Kg) of material into orbit- a fact that puts immense pressure on Astronauts to be constantly at their best. Add to that how easily poor judgement can jeopardize entire spacecraft, and it seems like recreational substances should be kept out of space entirely.

That sort of thinking (while totally well-founded) has prevented researchers from looking to unlikely allies in the fight against space-related cognitive decline. A number of researchers have taken to the problem with an engineer's prospective, trying to develop better radiation shielding and other tech that may not be perfected before mankind launches its first long-term manned missions. Developing better tech, while ideal, might not be the only available answer.

Having a chronic addiction to papers that aren't protected by a paywall, I read the abstracts and findings of hundreds of useless studies. In 2014, when I read "Long-term effects of marijuana use on the brain," I immediately suspected that what I read had immediate, valuable applications. ScienceAlert and other softcore science news outlets misreported the findings, suggesting that the brains of habitual users respond to a loss of grey matter in one region of the brain (the orbitofrontal cortex) by improving structural integrity elsewhere. In reality, the methodology of the study made it impossible to determine whether a "loss of grey matter" in the OFC was happening in response to habitual drug use. The authors of the paper noted that a smaller than average OFC in 12 year olds is predictive of later marijuana use- meaning that many of the subjects of the study could have had a smaller OFC to begin with.

What the study did illustrate is that neural connectivity (the number of connections between single neurons) increases steadily for the first 6-8 years of habitual use. Aside from situations where sudden and significant brain trauma triggers the brain to "rewire" itself, it was generally believed that once cells in the brain are damaged, that damage could not be repaired. This study was one of the first, but not the only one, to demonstrate that the brain can be tricked into performing this kind of repair in other ways.

Just a year prior to that, an experiment on mice conducted by the University of South Florida revealed similarly significant results. Working off a 2011 study that showed glucocorticoid receptors stimulate new growth in the hippocampus, researchers decided to test Psilocybin (which acts on a range of receptors) on a group of mice. Researchers hypothesized that giving mice a dose of the halucinogen would cause them to learn to fear painful stimuli more quickly, and exhibit those fears for longer than their sober fellows. When the lowest dosed mice overcame their conditioned fear response before the other groups, researchers were suprised to find that they had experienced significant new cell growth.

The point? Drugs that have been illegal to test on humans for the last half century or so are likely harboring helpful secrets in the battle against "space brain." Space damages the brains of astronauts in ways that we don't fully understand yet. Zero gravity changes the way blood is circulated in the body, and causes decreased function in multiple areas of the brain. Occasionally, energized particles impact and damage healthy cells at random, including neurons. Psychological strain adds yet another element of complexity to these problems, and that's in the relative safety of Earth orbit.

When mankind ventures beyond the safety of the Earth's magnetosphere, astronauts will be exposed to relatively high levels of cosmic radiation for long periods of time. In a study on mice and rats, both types of rodents were exposed to a range of radiated particles in levels similar to what an astronaut would experience. The effects on the animals were strikingly similar, and suggested that astronauts on these missions may develop:

• Brain inflammation
• Decreased neural connectivity
• Decreased ability to learn
• Diminished capacity for fear-extinction
• Poor memory
• Progressive cognitive defecits
• And long term anxiety disorders
  While development of drugs to reduce the impact of radiation on astronauts is underway, the focus is on making astronauts more resilient to radiation, rather than treating the long term side-effects of that exposure.

In the meantime, if there is a way to treat, or even to prevent, the neurological damage associated with long-term spaceflight, it would be irresponsible to overlook it. There's no reason to let our social stigma against "drugs" keep researchers from looking into what might be an immediate, achievable preventative measure. Members of a space crew need the highest degree of mental acuity possible at all times - erring on the side of an ingrained bias for "sobriety" may be too great a risk to take.

Proceedings of the National Academy of Sciences "Long-term effects of marijuana use on the brain" full paper
Article for the casual reader.

Effects of psilocybin on hippocampal neurogenesis and extinction of trace fear conditioning Full academic paper
Livescience summary for casual readers

A bit about Adult Neurogenesis

Cosmic Radiation exposure and persistant cognitive dysfunction Full academic paper on irradiated mice via Nature
LA Times article on "Space-brain" for casual readers