Thursday, August 14, 2014

Question about fragile X therapeutics

An astute reader asks: in light of recent experience, is the mGluR5 theory fatally flawed, and are there any other drugs which look promising?

In my opinion, the AFQ trials failed because of a dose range that was inadequate for fragile X, and because of the unexpected development of tolerance. Dosage problems are relatively easy to correct, but tolerance to the degree we observed may be a kind of fatal flaw, at least if we're talking about mGluR5 antagonists. The "mGluR Theory" is still probably correct; it's just that no one (least of all Novartis) expected tolerance to this drug---indeed, I'm not sure they would agree that's what happened. I think we saw a much better response than most people because our son was also on minocycline, effectively augmenting the response, and perhaps delaying the development of tolerance. This may be a clue to understanding the mechanism of tolerance, and how we can administer treatments for fragile X in the most effective way. We just finished the AFQ extension, and we're deep into the withdrawal now; withdrawal symptoms go hand in hand with tolerance, so this is to be expected, but it may also explain why some people in the trials did worse than placebo. A minor form of withdrawal is interdose rebound, and I suspect this was an issue for many people in the trial (though it's worth pointing out that few families thought their kids were actually worse on the drug; there were a few that got much worse, and I'll bet this is why.)

So, the mGluR Theory is still compelling, but we need to find another way to tone down the excessive mGluR signalling in fragile X. And we need to anticipate potential tolerance, and avoid drugs susceptible to tolerance. Incidentally, baclofen is well known to cause tolerance, so this may have been a problem in the arbaclofen trials, too.

Lithium modulates the activity of G-protein coupled receptor (GPCR, which includes mGluR) signalling, and has been extremely well validated in fragile X animal models. It has also been shown effective in preliminary clinical trials in fragile X subjects. Most importantly, given recent developments, lithium treatment does not result in any form of tolerance, at least not in the usual psychiatric indications. This is reassuring, and the use of this medication over the course of several decades in millions of patients, demonstrates that it is an effective therapeutic (whereas mGluR5 antagonist trials have failed in every case, for many different indications.)

There are 2 other possible explanations for the negative results from the Novartis trials. The one most often cited by virtually everyone in the field is the poor quality of the outcome measures available for fragile X clinical trials. These outcome measures, like the Aberrant Behavior Checklist and the Clinical Golbal Impression scales, are certainly crude instruments. There is little doubt that the "resolution" of these measurements is poor, and there is quite a bit of room for improvement in outcome measures for fragile X clinical trials. However, these trials simply did not show any hint of positive effect from the study drug (AFQ056); extensive analysis after the study ended ("post hoc analysis") showed absolutely no benefit from the drug compared to placebo.

There was one interesting result, though. Whereas many of the non-specific outcome measures (like CGI, VAS, and post-hoc narrative assessments from the clinicians) were essentially the same in placebo and all the drug dosage groups, the ABC scores got worse with higher drug dosage, and this effect was even statistically significant when the two trials (adult and adolescent) were combined. Now, this isn't a good result for the development of AFQ056, but it is interesting if we assume that the drug itself had no discernible effect (in other words, the result was a true negative.) We would expect that the drug group would have some side effects, that side effects would be greater at higher doses, and that in a special needs population side effects will usually express themselves as behavioral problems. So, if the drug doesn't work, you would expect the high dose drug groups would actually get a bit worse, and the ABC scores showed exactly that. Hmmm...maybe the ABC isn't quite as useless as everyone seems to think!

In any case, the outcome measures didn't doom this trial---the drug, as administered, simply didn't work (in most subjects.) The post hoc analysis didn't show even the tiniest suggestion of efficacy, and post hoc analyses always show something (this is another whole subject all by itself; using post hoc analyses can be an enormous tail-chasing exercise, with a host of new problems.) So, even when every detail could be examined outside the official trial protocol, a method virtually guaranteed to turn up something (at least a false positive!) turned up nothing at all. This gives us (well, me anyway!) great confidence that the drug didn't work the way was given. I doubt that the best outcome measures imaginable would have altered the results. Of course, we also need to re-visit the dosage issue. Most subjects in the trials were on doses that would be definitely sub-therapeutic; since dosing was fixed, and subjects were randomly assigned to dose groups, some people in the high dose group may have been on more than they needed. This isn't how psychopharmacology works in the real world; in clinical practice, we adjust the dose for optimal effects in each individual. However, in a clinical trial, this causes statistical headaches, so fixed dose groups are used.

So, the quest for improved outcome measures will continue.

The other possible explanation for the negative result (other than the obvious true negative condition) is that the effect is real but relatively subtle, possibly very gradual in onset, and not easily measured. In other words, it is below the level of resolution of any available outcome measure. But it is possible that AFQ monotherapy could have relatively little effect, while a rational drug combination could be quite effective. I have previously mentioned that we observed an excellent response to the study drug (though with significant subsequent development of tolerance.) Indeed, now that we have discontinued the AFQ, we know that the tolerance was only partial, because our son is clearly not doing well off the drug---probably some withdrawal symptoms mixed in with return of original fragile X behavioral symptoms. We are convinced that the drug has beneficial effects in fragile X, but our son is on other drugs, most notably minocycline. It seems quite possible that this makes a big difference, and that a combination of disease-modifying drugs may be needed to yield a therapeutic effect which is big enough to measure in this difficult environment. This is not unprecedented in medicine; for example, some antihypertensive drugs have relatively minor effects on blood pressure when given as monotherapy (and some show significant long-term tolerance), but are useful in combinations. All drugs push the system one way or another, but the system is designed to push back; more than one drug makes it harder for the system to compensate.

So, in the future, we'll be thinking about testing drug combinations in clinical trials. A more potent drug effect will also make it easier to validate new outcome measures, so this meshes well with the needs outlined above, and an integrated strategy is starting to take form!

Thursday, July 24, 2014

More on fragile X and MMP-9

Just in case we're all getting despondent about the prospects for fragile X treatment, it's worth remembering that there are many potential disease-modifying strategies---it's not just mGluR5! Another major article from the Ethell lab at UC Riverside has shown the therapeutic potential of drugs that inhibit MMP-9. A nice lay description of the new paper is here and the abstract of the article is here.

This latest work shows that human fragile X tissues have elevated levels of the extracellular enzyme MMP-9, as well as an increase in the active fraction of that protein (like most enzymes, MMP-9 can exist in an inactive form which can be switched on rapidly; this kind of regulation is important in most biological pathways.)

The Ethell lab also showed that genetic reduction of MMP-9 rescues most fragile X phenotypes in the mouse model. Previous work had shown that inhibition of MMP-9 with minocycline also had similar effects, but minocycline has many different actions. These experiments demonstrate conclusively that MMP-9 inhibition is the active ingredient. This is important, because pharma companies are working on drugs which inhibit MMP-9 without the antibiotic effects. They also showed that inhibition of this extracellular enzyme can normalize the activity of many of the intracellular signaling pathways (i.e. mTOR) that have been the focus of so much fragile X research. And, perhaps most interesting of all, they showed that genetic reduction of MMP-9 rescues the macro-orchidism phenotype in fragile X, something which has been relatively resistant to rescue with other therapeutic strategies. Since MMP-9 is a gelatinase, we have previously hypothesized that excessive MMP-9 activity in fragile X was responsible for the well-described lax connective tissue; confirmation that MMP-9 activity is indeed elevated in human fragile X tissue lends support for this idea, though this phenotype is difficult to measure in mice, so rescue effects were not assessed in this study.

All in all, this latest article adds to the growing body of evidence that MMP-9 dysregulation is a critical part of the pathology of fragile X, and MMP-9 should be considered a major treatment target for fragile X.

Saturday, July 19, 2014

What to make of the clinical trial failures in fragile X

To summarize: the official results from both the adult and adolescent trials of AFQ056 for fragile X were decidedly negative. Not only was there no improvement on pre-designated outcome measures, but subjects did a bit worse on the drug than on placebo (and placebo effects were robust, but in line with other trials in developmental disorders.) However, it is important to note that trial subjects got better on the drug, just not as much better as on placebo. Extensive analysis of the trial results after the fact ("post-hoc analysis") revealed no obvious differences in clinical responses between the different drug dosage groups and placebo. Subjects with a fully methylated fragile X mutation didn't respond any better than those with a partially methylated mutation, more severely affected subjects didn't respond any better than less severely affected (or vice versa.) So, the drug simply didn't work in any way that anyone can see or measure objectively, though many families reported excellent results, and most of the subjects in the open label extension continued on the drug, apparently satisfied with the drug's effect.

Our personal experience, which may have been a bit aypical because of co-administration of minocycline, was much more positive than the official results. Even so, the great results we saw at the beginning of the trial, and then during the first few months of the open label extension, just didn't last. We think there is still some beneficial effect at this point, but we were certainly hoping for continuous improvement.

The most important point is that this isn't just a problem with outcome measures. It would be great if we could attribute this negative outcome entirely to inadequate outcome measures. It's still possible, though increasingly implausible, to claim that the drug is actually improving cognition and other important developmental outcomes which aren't captured by the outcome measures, while at the same time having little beneficial effect (and even some adverse effects) on behavior. However, that isn't what we saw at all. We saw clear improvements in mood and behavior (not to mention reflux), and our son's ABC scores plummeted (before creeping back up later.) We have not seen any major leaps forward in development, or dramatic improvements in cognitive function. Now, improved behavior and mood can make everything seem better, at least for a while, and this may be what some families were observing. When people feel better, they generally do more and expand their range of activities. But this effect won't alter developmental trajectories. In other words, it won't be truly disease-modifying unless there is a sustained effect on all major fragile X symptom domains.

Where does this leave us, then? Well, first of all, mGluR5 antagonists probably won't be a viable treatment for anything if tolerance develops to this extent, and we've seen tolerance develop to the anti-reflux effects as well as the CNS effects. It's no coincidence that so many of the mGluR5 programs around the world have failed and been discontinued. This implies that this target many not be viable for fragile X therapeutics, although it is possible that trials of higher doses of mGluR5 antagonists, perhaps in combination with other drugs, could still be effective. However, this greatly complicates the "re-purposing" strategy, since most drugs are developed with a particular dose range in mind, and most drug companies would need to go back and repeat this process specifically for fragile X. It is not likely that any company will be enthusiastic about incurring this expense in light of recent experience.

We have many more thoughts about where the fragile X research field needs to go, and we'll discuss those ideas in future posts.

Monday, June 30, 2014

Further thoughts on our AFQ experience

So, the Novartis trials ended with a rather negative result. But we did see a lot of positives in our son along the way. Could it be that there was something about our case that made a response more likely? Well, I do think that the combination of minocycline and AFQ056 was probably much more effective than just AFQ alone. The preclinical evidence for minocycline as a disease-modifying agent in fragile X is very strong, and the clinical trials done to date, though probably not rigorous enough to be considered definitive proof of efficacy, have been positive (unlike some others!) It stands to reason that a combination of two drugs would work better, given that fragile X is a disorder that affects the brain globally. In other words, one drug might work well in one area of the brain, but not fix everything; another drug might work well in other areas or other pathways, so that the combo gives greater "coverage" and a better clinical response, especially with the rather crude outcome measures we're using. It would be interesting to see if trial subjects on minocycline had any better pattern of response, but I doubt there were enough subjects on the combination to analyze properly (especially since many of the subjects were outside the US, where minocycline use in fragile X is much less common.)

One question I've been asked a few times is, if there is tolerance developing to mGluR5 antagonists, why don't the rating scales from the trials show that? Why don't we see the scores go down, then back up? Of course, all of the above has an effect---most subjects aren't getting enough drug effect to notice in the first place. But this is also where the shortcomings of the outcome measures may come into play. The resolution of these rating scales, especially in the context of moderately large placebo responses, is simply nowhere near good enough to quantify tolerance (although, I should note that our scores did go way down, then back up a bit toward the end of the study; I believe our son's clinician ratings also showed this.) It's also quite possible that there are sub-groups of fragile X subjects who are particularly responsive to one drug or another. We've had friends who participated in both the arbaclofen trial and one of the mGluR5 trials, and some have had terrible experiences with one, but great effects from the other. Ideally, you'd like to be able to predict who would do better, either with a biomarker or via phenotypic features, but there's nothing available right now to do that. Indeed, we are caught in a bit of a Catch-22 scenario: we need to have a clinical trial success to demonstrate which outcome measures, biomarkers, and endophenotypes are most useful, but we need to have some of those things first to have successful clinical trials!

Perhaps one solution is to have pilot trials with combination treatments, as a way of getting more robust and reliable effects from the drugs. This would allow for better study of outcome measures and biomarkers, and it would allow us to figure out which ones are actually drug-responsive. It may be unrealistic to expect that any one drug can move the needle far enough to be measurable, but a two drug combo may have a better chance of success.

Wednesday, June 25, 2014

Novartis trial results are in, and they're not pretty

This year's Gordon Conference just finished,and Novartis presented their results for the first time (though advisors and advocates had been given a private peak months ago.) To say that the trial results for AFQ056 were disappointing would be the understatement of the century! While the company has already announced that the adult and adolescent trials failed to meet their pre-designated endpoints, the numbers looked really bad. This wasn't a case of the drug working, but placebo effects leading to an outcome that wasn't statistically significant; in this case, the effect of the drug was statistically significant, but in the wrong direction!

So, what went wrong? The evidence for using mGluR5 antagonists in fragile X was really strong going into these trials---in fact, about as good as it ever gets. The drug itself was an advanced compound that had been studied extensively. Of course, outcome measures have been a problem, and they're definitely not good enough. However, Novartis did an exhaustive analysis of all the data, plus they even went back and looked again at subjects who were reported by clinicians and caregivers as exceptionally good responders. None of this "post hoc" analysis revealed any positive effect of the drug compared to placebo---not even a glimmer of hope in adults or adolescents (and both trials came up with very similar results, providing some degree of cross-validation). The ABC and other outcome measures used might leave much to be desired, but they weren't the reason for these trial failures. Indeed, the trials were not "failures" in any sense, except that the results were decidedly negative. Novartis conducted an excellent pair of clinical trials which showed convincingly that AFQ056 doesn't work for fragile X, as least not as administered in these trials.

Perhaps the Roche compound will show much better efficacy; it is a different drug, and somewhat different methods are being used in the Roche trials. But our personal experience may offer some insights into what is going on, and this also leads me to be a bit pessimistic about the chances for mGluR5 antagonists in general.

Our 25 year-old son was one of the last adults enrolled in the AFQ trial; I should note that he was also on minocycline during this entire time, as he has been for many years. This is thought to have potentially disease-modifying properties for fragile X, and so this may have boosted the effect of the AFQ. His other meds are valproate, topiramate, and sertraline. He also has a lot of severe gastro-esophageal reflux, which means he spits up his food a lot if he eats too fast (it seems to be reflux, which is a physical effect based in the stomach and esophagus, rather than nausea, which is a centrally mediated process controlled by the brain.) In any case, when he started the blinded phase of the trial, we saw a rapid improvement in his mood, language, social function, and basically everything else. But we only saw one "bump" up during the dose titration, which led us to think he was on the lowest dose of the drug (this was later confirmed.)

Unexpectedly, his reflux went away entirely along with all this other improvement; I should also note that this was all after the 4 week placebo run-in (we'd been tipped off about that long ago!) But this is a guy who had never in his life gone for a whole week without barfing; this was a regular, daily event for us. Our son had not one single episode of reflux for more than one month after starting on that tiny dose of AFQ! Call it a side effect, or a bonus, but it was something very objective and hard to ascribe to placebo. Indeed, mGluR5 antagonists are known to increase tone in the lower esophageal sphincter, and have been studied as treatments for reflux. The first 6 weeks or so were great---we started doing all kinds of new things, like sailing and traveling, dining out and going to lots of new places. This, I thought, was what we had been waiting for! But then the effect started to wear off, little by little. The reflux came back, though only a bit here and there.

We figured this was no big deal, that in the extension phase we'd get to a higher dose and that would work much better. Which turned out to be true! When we started the open-label extension, our son got noticeably better with each dose increase, and tolerated the full 100 mg twice a day with no side effects to speak of, except the good one (no reflux at all!) This kept up for several months, and we were very happy. We assumed that things would just keep getting better and better as long as we kept up the AFQ. However, after a while (hard to say exactly when, because I think it was very gradual), many of the old behaviors started creeping back in, as did the reflux (in fact, they seemed bound together quite tightly.) As I write this, about 9 months after starting the full dose of AFQ, I'd estimate we've lost about 70-80% of the effect of the drug. We're probably not all the way back to baseline, but we're not finding that things are getting better and better all the time.

Now, even I realize that the placebo effect is very powerful, and that we are hardly objective observers in this case. I could easily be imagining improvements in mood or behavior, or we may have treated our son differently because of our expectations, leading to better behavior. But I can't explain the reflux as anything other than a real, physical effect. He ate the same food, the same way as ever. The mGluR5 antagonist simply helped him keep it down---it's known to do that. But even that effect wore off! Tolerance developed to that physical effect at approximately the same rate as the "central" effects that were the primary objective in this case.

So, in a nutshell, the problem we've seen, and the likely reason for the trials to fail, has been the development of extensive tolerance. This is quite unexpected, it's probably something intrinsic to mGluR5 in fragile X, and something I'll discuss more in upcoming posts.

Wednesday, March 20, 2013

It’s not just mGluR5…there’s more than one way to fix fragile X



In case you somehow got the impression that FRAXA is only interested in mGluR5 research, or that we’ve quit funding basic research altogether, the most recent edition of the Proceedings of the National Academy of Sciences (PNAS) illustrates just why that’s not true.

Long after the seminal finding of increased mGluR-LTD in fragile X by Kim Huber and Mark Bear, FRAXA funded studies by Nobel-laureate Susumu Tonegawa investigating the role of the enzyme PAK in regulating the shape and function of dendritic spines. The results of this FRAXA-funded project demonstrated that genetic reduction of PAK could rescue most fragile X knockout “phenotypes” (the animal model equivalent of human symptoms.) This was essential proof of concept work which established PAK inhibitors as potential therapeutics for fragile X, and was the basis for a new company called Afraxis. The only problem was that no specific PAK inhibitors actually existed at that time, but Afraxis has been busy trying to find useful drugs that inhibit PAK (actually a family of enzymes, not one single enzyme.) The paper just published by Tonegawa and his collaborators from MIT, Afraxis, and universities in India and Korea, shows that a new compound which Afraxis calls FRAX486, inhibits all the PAKs in the brain at relatively low doses, and displays all the properties you’d expect of a useful drug. Most importantly, it appears to reverse most of the important animal model phenotypes with a single dose (though, presumably, daily dosing would work better as a human therapy.)

Read the whole thing: http://www.pnas.org/content/early/2013/03/14/1219383110.full.pdf+html?with-ds=yes

At this point, FRAXA has developed a large pipeline of drug candidates for the disease-modifying treatment of fragile X. We continue to fund basic research looking for more promising leads, but our main emphasis is on developing treatments based on the work we’ve already funded, which has given us plenty of candidates for therapeutics that can alter the course of fragile X. We’re excited about our partnerships with companies big and small, like Afraxis, because these partnerships are essential to bring new treatments to fragile X families in need.

Sunday, December 2, 2012

An internet friend asked for my feedback on the following article:

Primum Non Nocere: An Evolutionary Analysis of Whether Antidepressants Do More Harm than Good

Abstract

Antidepressant medications are the first-line treatment for people meeting current diagnostic criteria for major depressive disorder. Most antidepressants are designed to perturb the mechanisms that regulate the neurotransmitter serotonin – an evolutionarily ancient biochemical found in plants, animals, and fungi. Many adaptive processes evolved to be regulated by serotonin, including emotion, development, neuronal growth and death, platelet activation and the clotting process, attention, electrolyte balance, and reproduction. It is a principle of evolutionary medicine that the disruption of evolved adaptations will degrade biological functioning. Because serotonin regulates many adaptive processes, antidepressants could have many adverse health effects. For instance, while antidepressants are modestly effective in reducing depressive symptoms, they increase the brain’s susceptibility to future episodes after they have been discontinued. Contrary to a widely held belief in psychiatry, studies that purport to show that antidepressants promote neurogenesis are flawed because they all use a method that cannot, by itself, distinguish between neurogenesis and neuronal death. In fact, antidepressants cause neuronal damage and mature neurons to revert to an immature state, both of which may explain why antidepressants also cause neurons to undergo apoptosis (programmed death). Antidepressants can also cause developmental problems, they have adverse effects on sexual and romantic life, and they increase the risk of hyponatremia (low sodium in the blood plasma), bleeding, stroke, and death in the elderly. Our review supports the conclusion that antidepressants generally do more harm than good by disrupting a number of adaptive processes regulated by serotonin. However, there may be specific conditions for which their use is warranted (e.g., cancer, recovery from stroke). We conclude that altered informed consent practices and greater caution in the prescription of antidepressants are warranted.


Read the whole thing at: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3334530/

It's always interesting to read and critique articles like this, because it gives me a chance to think about the Big Picture---in fact, I think I'll expand on this and make it into an extra-long blog post. I guess this article was thought-provoking; it certainly got my juices flowing, mainly because a lot of people ask me questions related to the points made in this article, and I think it’s important to answer these questions, because it’s easy to scare people away from the medical treatment they need. Some might say I'm biased, because I prescribe drugs; however, I've also done many thousands of hours of psychotherapy, too.

As an overview, this article is typical of its genre, and can be seen as part of the ongoing psychology/psychiatry turf war. It's not really just science, but also an opinion piece from people with an ax to grind, and probably some vested interest. The article is of poor quality, and the authors clearly do not understand many of the basic neuroscience topics they are purporting to review; many of the references are review articles, not original studies, and rely heavily on their own previous review articles and on those of co-authors who clearly run in the same circles. This is OK when you're in a small field, but this is not a small field. They are using a tiny fraction of the literature to support an opinion (that antidepressants do more harm than good) which is absolutely not supported by the weight of the available evidence. They also have an annoying habit of stating something non-controversial (i.e. serotonin is in platelets) and referencing that extensively, then asserting something outrageous without any reference at all---the journal reviewers shouldn’t let them get away with this, so this speaks to the quality of the journal.

It is always true in the life sciences that there is some contradictory evidence, no matter the subject. We don't know everything, and our concept of how the brain works will be evolving for a long time to come---certainly for the rest of our lives, and then some. We cannot be paralyzed by what we don't know when there is real human suffering. Depression, anxiety disorders, and other associated conditions which are commonly (and very effectively) treated with these medications exact an enormous human toll, and if we're going to wait until we understand everything about them before we start treating, we're going to be waiting for a very long time. We do the best we can with basic neuroscience research, translational research on disease mechanisms, preclinical research in animal models, and then carefully controlled clinical trials. The science is never settled, and our understanding is always subject to review (remember that when you hear other scientific issues discussed in the popular press.)

One of their main points is that there is a carefully regulated and highly evolved homeostasis in all these systems (i.e. serotonin), and that anything that perturbs it must necessarily cause dysfunction. You could say this about any medical treatment for any condition, so I guess all of modern medicine is suspect from this point of view (with the possible exception of antibiotics, but they'd probably argue that perturbing normal flora is dangerous, too.) The point they're obviously missing is that the system is already perturbed, and that's why we have a disease state. Some of the authors have previously written that depression (and by extension, just about any mental illness) is just a normal evolutionary response; that may or may not be true, but we haven't evolved much at all (genetically speaking) as a species in the last 10,000 years, while our lifestyle has changed radically. The same is true for the extensive discussion of withdrawal and discontinuation effects in the article; while it's certainly true that many patients relapse when antidepressants are discontinued, that’s also true for virtually all medical treatments of chronic (i.e. non-infectious) diseases. When patients stop taking antihypertensives, blood pressure rebounds---often higher than ever. If an epileptic patient stops taking seizure meds, more seizures are likely. If a diabetic stops taking insulin, they’re still diabetic, and their blood sugars go up. All of this is expected, yet the authors seem to proclaim that they have discredited antidepressants with this revelation.

The surprising thing is how few patients actually relapse---if it’s done right, most people are able to discontinue their antidepressants and have something like a lasting “cure”. Of course, the devil’s in the details, and it’s often not done right. It would be nice to have more research in this area, and much is underway; in the meantime, good clinicians have figured out the best methods for successful discontinuation. My clinical pearls: treat for at least a year at the optimal dose (longer if the depression is more chronic), then decrease the dose very gradually, and do it at a time of year that’s good for the individual patient (often, Spring is the best time of year.)

They really get bogged down when talking about neurogenesis; they mistakenly assert that neurogenesis is widely considered to be the mechanism of action of antidepressants; this is one theory, but not the consensus or established view by any means, so I'm not sure why they spend so much time and effort trying to poke holes in one theory of antidepressant mechanism of action. Anyone who’s ever spent any time thinking about this has come to the conclusion that the antidepressant response is essentially an alteration of gene expression (one manifestation of which might be increased neurogenesis, but it’s hard to imagine that’s the full extent of it.) All the different monoamine manipulations caused by available antidepressants are likely just means to an end, different ways of altering gene expression in the brain. It is no accident that hormonal alterations like increased cortisol or decreased thyroid hormone, which are thought to cause some cases of depression, are also known to cause widespread alterations in gene expression. There are probably many ways to get depressed or anxious, and the available treatments are just ways that we’ve found to (partially) reverse those processes.

The authors argue that the evidence for enhanced neurogenesis with SSRIs and other antidepressants is equivocal. Since there are hundreds, even thousands, of studies demonstrating this phenomenon in many different ways (not just the one they critique) and a relative handful that show a negative result, you could call that "equivocal", but I would call it a preponderance of evidence. Remember, there is always conflicting evidence in science! They speculate that if neurogenesis is increased with antidepressants, you should see more brain tumors. This is incredibly silly, and something they just made up (no reference at all, because it just isn’t true!) Neurogenesis does not lead to neoplasia (cancer) at all---those are two entirely distinct phenomena, and anyone with any medical training would know that. If neurogenesis is increased, you would expect to see more seizures with antidepressants---and you do! All known antidepressants result in a small but significant increase in seizures in trial populations; the risk isn’t great, but it’s there, and it’s probably a direct manifestation of increased neurogenesis. The interesting thing is that antidepressants vary widely in their seizure risk, but this does not correlate with antidepressant efficacy. SSRIs are low-risk, while other drugs like maprotiline (Ludiomil) and bupropion (Wellbutrin) are clearly much higher-risk. This suggests to me that neurogenesis is a sideshow, and not the primary antidepressant mechanism, but that’s just my opinion.

The article also spends a lot of time emphasizing the point that antidepressants just don’t work as well in clinical trials as most folks might imagine, and that there have been many trials (often unpublished) where the antidepressant fails to separate from placebo, or has a very small effect size. To some extent this is true, especially for those who don’t really understand drug trials, and just how difficult they are to conduct. What happens when a clinical trial isn’t properly designed and conducted? The result is that improvement on drug is not statistically superior to placebo; note that this does not mean that the trial drug doesn’t work. It could mean that, or it could mean that the trial simply wasn’t well done, for any number of reasons. However, it is exceedingly unlikely the drug would show superior efficacy compared to placebo by chance, or because of poor methodology. So, it’s a kind of one-way street: virtually all problems (other than outright fraud) lead to a result not significantly different from placebo. Positive trial results are important, and they are accorded great significance for just this reason---they are very hard to come by, because the system is heavily biased against a positive outcome in any double-blind trial. Of course, there are limits to this. If a drug goes through 20 trials, and only one shows significant efficacy compared to placebo, then it’s probably not a very effective drug. But if a drug is in 20 clinical trials, and only 12 are positive, that’s not bad (and fairly typical in psychiatry.) That is an effective drug, and the FDA understands that. It’s also important to understand that most subjects in clinical trials are chronic, difficult, treatment resistant patients; it is rare to find drug-na├»ve subjects in any psychiatric clinical trial. So, critics of antidepressants are always fond of citing big meta-analyses, where results are pooled from all the available studies, good and bad. This invariably diminishes the effect size and increases the placebo effect compared to the more successful, well-done studies. Psychiatric research is just like any other human endeavor, some of the people doing it are incompetent, and their efforts muddy the waters for everyone else.

In the real world, we tend to see much higher response rates among the general population. For example, in my practice of young and middle-age adults in a private outpatient setting, I generally found a response rate to SSRIs for depression and anxiety disorders of about 90% in patients on their first med trial---well in excess of the usual 70% response rate in most clinical trials. These were real, life-changing responses to treatment, with no “poop-out” after a while. Placebo responses never last, so I’m confident that most of these were real therapeutic effects. My success rate in discontinuing the antidepressants in this category of patients was about 60%, using my conservative methods; the unsuccessful 40% went back on the same medication, at the same dose, and virtually always did fine until the next time they wanted to attempt drug discontinuation.

This paper also includes a rather histrionic recitation of side effects of meds, focusing on SSRIs. Of course, all medications have side effects; it’s really surprising how many side effects are reported even in placebo-treated subjects. But most people on SSRIs don’t have major side effects, and many never notice anything at all; the body does adjust, so that the reported side effects usually dissipate as treatment goes on. Here again, this is not really different from what we see with any medical treatment. The authors go into gory detail about the risks of very rare side effects like hyponatremia (I’ve never seen a single case with any antidepressant---I have seen a bunch with the anticonvulsant Tegretol), and try to demonstrate that SSRIs cause cognitive impairment (there’s no evidence of it, and it has been tested directly.) Throughout, they make the most common mistake people make in this situation: they compare the rates of various problems in depressed people treated with antidepressants to the rates seen in normal untreated people. The problem is that depression causes many of these problems, like cognitive impairment, suicide, and excessive cardiac deaths. So, it’s hard to separate the symptoms of the disease from the side effects of the treatment.

I would also note that psychotherapy is not without side effects, especially since the authors seem to have the agenda of promoting psychotherapy. Now, I trained extensively in long-term, psychodynamic psychotherapy; I’ve done lots of it, and I’m very much in favor of it, as well as newer focused psychotherapy approaches. But I’ve also seen many patients (and some personal friends) devastated by poorly done or inappropriate psychotherapy. Drug side effects are usually easy to fix---just stop the drug. The kind of damage inflicted on these folks by incompetent psychotherapists can never be undone, not to mention the financial ruin and exploitation that went along with it. Most people assume psychotherapy has no side effects because they also assume it doesn’t do anything at all. Neither assumption is true.

As a final note, there have been several long-term studies of brain volume in people with depression (and similar studies in OCD). Having depression shrinks your brain on CT or MRI, and treatment with antidepressants (doesn’t seem to matter which ones, as long as they’re clinically effective) prevents this. This is a very powerful argument against most of the pseudo-biological speculation offered in this article, yet the authors gloss over these inconvenient facts entirely. Depression is very bad for your brain; antidepressants clearly help. Are they perfect? No, but their benefits clearly greatly outweigh their risks in the vast majority of people with serious Mood Disorders and Anxiety Disorders.