(I know, I know: you'd be far worse off without the one that worked for you. Hey: they do some good. For some people. I want better drugs for you, is all. And we were promised them with the 2000 mapping of the human genome. So...where are they? Later.)
The drugs people use - by every estimate I've seen between 20% to 25% of the Unistat population takes at least one of these - were discovered by accident. By serendipity. In the 15 years after 1945. In 1952 a tuberculosis drug didn't work for TB, but iproniozid sure elicited euphoria when tested! Bingo: the first antidepressant. The drug that became Tofranil was supposed to work for schizophrenics, but it didn't help them, only make them run naked into town, laughing. Another antidepressant. In 1949 lithium was discovered, by accident, to treat manic depression. In 1957 Leo Sternbach was about ready to give up his research into a class of antihistamines, things were looking like a dead-end, when he stumbled onto the benzodiazepines: your Valium, Xanax, Lorazepam, Klonopin, etc: an empire of anti-anxiety drugs, and a huge influence on the tonality of culture in the West in the latter half of the 20th century.
With better technics, we learned much more about neurons and neurotransmitters. The SSRIs seemed to treat depression and anxiety. They were really the last big breakthrough. Ever since then, clinical trials that have made it to Stage III have been nothing but huge, sad, very expensive wastes. And so Novartis, Glaxo-Smith-Kline, Astra Zeneca, Pfizer, Sanofri and Merck have by and large quit trying. They've halted clinical trials, moved onto research that shows more promise. The pipeline for new psychopharmacological drugs is dry.
Wait a minute: with more neuroscientists than ever before, far better imaging devices, a tremendous acceleration of knowledge about the human brain over the past 30 years...why? And mental health takes an increasing toll on us. If not you, someone you know. Why is this so difficult? Is it because what R.D. Laing called "the medical model" finally showed its hand? (A pair of nines?)
Again: our technology to map with ever finer-grains our cells, genes, and organs is greater than ever. We now have a deeper understanding of the human genome, an explosive discovery of the complexity of the epigenome, increasing understanding of how our environment and microbes interact with us...why don't we have a drug that will cure depression by now? Are we simply too complex to understand? Were we destined to be granted a brief window of time in which a few "happy accidents" would yield up as good as it gets, and it all ended 30 years ago? What about our computing power and pharmacological knowledge? Isn't it also subject to Moore's Law: a doubling roughly every 18 months? Shouldn't we have had a bevy of breakthroughs by now?
What are we doing wrong?
In 2011 Eli Lilly thought they had a breakthrough for schizophrenia. They'd given PCP to mice, then their new drug and...the mice calmed down! Everything went well. They got to Stage III clinical trials (humans) and 18 months later the drug was dead. Placebos worked just as well. Lilly is another company that has all but given up now too.
Some New Ways of Thinking and Genuine Promise
Steven Hyman of Harvard and M.I.T. knows this field well. He was quoted in an article I read as admitting of his colleagues, "People are tired of curing mice."
Let's go back to the last breakthough: Prozac and all its cousins.
It had been assumed that, when those happy accidents occurred, there must be a theoretical basis. Pharmacologists have always acted like they were on top of what was going on, but the trade secret was they were faking it: when a drug worked, it went on the market, people used it and they "worked" well enough, but at first the chemists and psychiatrists had no idea why. With better understanding of the brain, they found the ancient model of the imbalance of humors as an explanatory scheme. Only they juiced it up: they found these drugs altered neurotransmitters. Therefore, the lack of the neurotransmitter caused the disease! It seemed quite plausible, and very much like the hardcore finding that insulin works for diabetics.
Nassim Nicholas Taleb says this is a classic case of the "reverse-engineering problem": drop an ice cube on the floor and then go play cards with your friends in the other room. Can you visualize the cube breaking down into a tiny pool of water? Of course you can. You walk back into the kitchen and see a tiny pool of water where you had dropped the cube. It's pretty straight-forward. Now: imagine walking down the street and coming upon a tiny pool of water. A little spot of wet. How many ways can you dream up the cause of this spot?
A cop comes upon a drunken man looking for his keys, at night, under a streetlight. The cop asks the drunk why he keeps looking under the streetlight, and the drunk says it's because the light is so much better there.
Obviously, even our best researchers have been looking where the light was bright. And the reverse-engineered explanation of our not-all-that-great/we-can-do-better psychopharmacological drugs? Human. All-too human.
The neurotransmitters are not the cause of the mental illness. They merely point at the underlying cause; neurotransmitters (dopamine, serotonin, norepinephrine, etc) are tangential and partial. Reverse-engineering to allow more serotonin to remain in the synaptic gap between neurons was a genius move; too bad there are a handful of studies that show SSRIs work little better than placebos. (For some people they have worked well enough; I don't want to slight this!) All in all, there's a "truthiness" about depression drugs.
We treat everyone the same in studies, while knowing they have variable epigenomes. This is receiving some major research and seems quite promising, to my eyes. We have a semantic problem with experts dealing with a patient, making observations and tests, then naming the disease they "have," which is a major problem: people and diseases do not fall into our socially-constructed and convenient categories as well as we'd like. This problem is now far more acknowledged than ever, which seems promising to me. One example is the Research Domain criteria: we map behavioral abnormalities and symptoms and link them to specific causes in the brain, without the label of "schizophrenia" or "panic disorder." Why is this approach better? Because it's more targeted. Instead of looking at one or two neurotransmitters that "cause" schizophrenia, we try to find out specifically what causes people to hear voices, or become catatonic.
The idea that we must take 18 years from conception through clinical trials is being re-thought. Even more crucially for mental disease: non-human animal studies long ago reached diminished returns. Now the idea is small-scale, carefully controlled studies on humans will speed up the process and may yield breakthroughs in shorter periods.
Another area of promise: when a drug failed, it often worked for a few people. But our gold standard of drug testing: double-blind and placebo-controlled? The rules were that if the placebo worked as well as the drug, throw out the drug. But the people who were helped probably should have told us something.
Along those lines, there is a strong call to restore abandoned or "invisible" clinical trials to correct the scientific record. We may learn some very interesting things from "failed" trials.
The techniques surrounding stem cells have accelerated at an incredibly dizzying pace upward and for the better: now researchers can test cells and drugs in a a dish and make very good guesses as to whether a compound would have some efficacy.
With the mapping of human genome in 2000, hundreds of utopian promises were made that now seem embarrassing or outright quackery. But there was reason to be optimistic. We thought because we were very complex, we'd have the most genes, but instead of 100,000 we only had about 21,000. Grapes have more genes than us: this was nothing like what we'd expected. Worse: 13 years later we now know that a "bigger" system - in terms of complexity - governs the genome: the epigenome. It turns out that RNA plays a far, far bigger part than we'd thought. The complexity can seem overwhelming.
In 2002 researcher Andrew Hopkins came up with an eye-opening paper, the "druggable genome": Okay: we'd thought we had 100,000 genes. We have closer to 21,000. He estimated that only about 10% of those genes coded for proteins that could bind to small molecules, which is how drugs work, basically. So: about 2,100 genes. But he estimated that, of those, only about 20% would be likely to involve diseases. So now we're down to about 420 possibilities for targets. And then he guessed we'd already discovered 50% of those (probably accidentally?). We only had 210 targets left? For all diseases, not just mental illnesses? Not exactly a rosy scenario. But...
Cheminformatics! This is a burgeoning discipline using the aforementioned computational doubling: there are tens of thousands of compounds in digitized libraries. Do you test them all? Two guys wrote an algorithm to teach a computer to sift through a welter of data on TB, which is becoming antibiotic-resistant. A Big Deal, quite threatening to all of us, potentially. Their algorithm said: find all compounds that are like the drugs that used to work on tuberculosis. So you get that data set. Then the algorithm says, throw out every compound known to be toxic to mammalian cells. You have a smaller set, but a safer one to work with. The algorithm discovered a 40-year old drug that was shown to have anti-TB properties but had been forgotten.
Even more interesting and promising: researchers in Cambridge, MA have taken messenger RNA (mRNA), an ultra fragile molecule which, when injected activates the body's immune response, tweaked a couple of "letters" in its nucleotide sequence, and made a non-fragile mRNA that does not turn on the immune system. What this could do is take the information from the DNA in a gene and make it "fix" missing or broken proteins in another cell, in effect causing a patient with a (probably inherited?) protein abnormality to make a drug inside their own cells!
Nessa Carey, a gifted explainer of how epigenetics works in our bodies, has urged us to be cautious about getting too excited over drugs based on DNA-RNA, because so far, "One of the major problems with this kind of approach therapeutically may sound rather mundane. Nucleic acids, such as RNA-DNA, are just difficult to turn into good drugs. Most good existing drugs - ibuprofen, Viagra, antihistamines - have certain characteristics in common. You can swallow them, they get across your gut wall, they get distributed around your body, they don't get destroyed too quickly by your liver, they get taken in by cells, and they work their effects on the molecules in or on the cells. Those all sound like really simple things, but they're often the most difficult things to get right when developing a new drug."
Finally, there is a very real call to combine all our new technologies with an active looking for happy accidents, like in the 1945-60 period. We find as many compounds that could possibly have efficacy, get people willing to be guinea pigs to try them (we have far better ways to guess at what's likely to have horrendous side effects or death-dealing qualities, but we're by no means "covered" here), and see what happens! Yes, the dark side is that the poor will probably be the ones to sign up...How do we find new things to try? "Scientists Map All Possible Drug-Like Chemical Compounds." It turns out the drunk looking for his keys was far more accurate an analogy than we might've guessed. Or wanted to guess. Check out all the unexplored chemical "space" yet to be charted! It reminds me of the incredible number of phenethylamines and tryptamines that Alexander Shulgin mapped: but a drop in the ocean? (Shulgin deserved the Nobel Prize for Chemistry: just read-up on his career! It's almost criminal he didn't get the Prize.) It's like looking for signs of life in the Milky Way! Or more prosaically: like geologists learning how to more profitably drill for oil. It's also about algorithms and possibilities and adventure and hellacious mistakes yet to be made.
To all of us looking for better living through chemistry: Bon appetite! I do think we may make it through this bottleneck to a whole new world of more sophisticated drugs that will make all the ones we've had since 1945 look primitive. Maybe?
Some Of The Works Consulted:
The Epigenetics Revolution by Nessa Carey
"No New Meds," by Laura Sanders:
http://www.sciencenews.org/view/feature/id/348115/description/No_New_Meds
Happy Accidents: Serendipity In Modern Medical Breakthroughs, by Morton A. Meyers
"The Psychiatric Drug Crisis" by Gary Greenberg:
http://www.newyorker.com/online/blogs/elements/2013/09/psychiatry-prozac-ssri-mental-health-theory-discredited.html
PIHKAL: A Chemical Love Story, by Alexander and Ann Shulgin
"Where Are All The Miracle Drugs?" by Brian Palmer:
http://www.slate.com/articles/health_and_science/human_genome/2013/09/human_genome_drugs_where_are_the_miracle_cures_from_genomics_did_the_genome.single.html
"Messenger RNAs Could Create a New Class of Drugs," by Susan Young:
http://www.technologyreview.com/news/512926/messenger-rnas-could-create-a-new-class-of-drugs/
"Faster, Smarter and Cheaper Drug Discovery":
http://www.sciencedaily.com/releases/2013/03/130321131920.htm
Serendipity: Accidental Discoveries In Science, by Royston Roberts
Hope or Hype: The Obsession With Medical Advances and the High Cost of False Promises, by Richard A. Deyo and Donald L. Patrick
"Experts Propose Restoring Invisible and Abandoned Trials to 'Correct the Scientific Record'":
http://www.sciencecodex.com/experts_propose_restoring_invisible_and_abandoned_trials_to_correct_the_scientific_record-114055
The Black Swan: The Impact of the Highly Improbable, by Nassim Nicholas Taleb
