Abilify for Bipolar Maintenance: More Hard Questions

May 31, 2011

Much attention has been drawn to a recent PLoS Medicine article criticizing the evidence base for the use of Abilify as maintenance treatment for bipolar disorder.  The major points emphasized by most critics are, first, that the FDA approved Abilify for this purpose in 2005 on the basis of flawed and scanty evidence and, secondly, that the literature since that time has failed to point out the deficiencies in the original study.

While the above may be true, I believe these criticisms miss a more important point.  Instead of lambasting the FDA or lamenting the poor quality of clinical research, we psychiatrists need to use this as an opportunity to take a closer look at what we treat, why we treat, and how we treat.

Before elaborating, let me summarize the main points of the PLoS article.  The authors point out that FDA approval of Abilify was based on only one “maintenance” trial by Keck et al published in 2007.  The trial included only 161 patients (only 7 of whom, or 1.3% of the total 567 who started the study, were followed throughout 26 weeks of stabilization and 74 follow-up weeks of maintenance).  It also consisted of patients who had already been stabilized on Abilify; thus, it was “enriched” for patients who had already shown a good response to this drug.  Furthermore, the “placebo failures” consisted of patients who were abruptly withdrawn from Abilify and placed on placebo; their relapses might thus be attributed to the researchers’ “randomized discontinuation” design rather than the failure of placebo.  (For more commentary, including follow-up from Bristol-Myers Squibb, Abilify’s manufacturer, please see this excellent post on Pharmalot.)

These are all valid arguments.  But as I read the PLoS paper and the ongoing discussion ever since, I can’t help but think, so what??  First of all, most psychiatrists probably don’t know about the PLoS paper.  And even if they did, the major questions for me would be:  would the criticism of the Keck et al. study change the way psychiatrists practice?  Should it?

Let’s think about psychiatric illness for a moment.  Most disorders are characterized by an initial, abrupt onset or “episode.”  These acute episodes are usually treated with medications (plus or minus psychotherapy or other psychosocial interventions), often resulting in rapid symptomatic improvement—or, at the very least, stabilization of those symptoms.

One big, unanswered (and, unfortunately, under-asked) question in psychiatry is, then what?  Once a person is stabilized (which in some cases means nothing more than “he’s no longer a danger to himself or others”), what do we do?  We don’t know how long to treat patients, and there are no guidelines for when to discontinue medications.  Instead we hear the common refrain:  depression, schizophrenia, and bipolar disorder, are lifelong illnesses—”just like hypertension or diabetes”—and should be treated as such.

But is that true?  At the risk of sounding like a heretic (and, indeed, I’d be laughed out of residency if I had ever asked this question), are there some cases of bipolar disorder—or schizophrenia, or depression, for that matter—which only require brief periods of psychopharmacological treatment, or none at all?

The conventional wisdom is that, once a person is stabilized, we should just continue treatment.  And why not?  What doctor is going to take his patient off Abilify—or any other mood stabilizer or antipsychotic which has been effective in the acute phase—and risk a repeat mood episode?  None.  And if he does, would he attribute the relapse to the disease, or to withdrawal of the drug?  Probably to the disease.

For another example of what I’m talking about, consider Depakote.  Depakote has been used for decades and is regarded as a “prototypical” mood stabilizer.  Indeed, some of my patients have taken Depakote for years and have remained stable, highly functional, and without evidence of mood episodes.  But Depakote was never approved for the maintenance treatment of bipolar disorder (for a brilliant review of this, which raises some of the same issues as the current Abilify brouhaha, read this article by The Last Psychiatrist).  In fact, the one placebo-controlled study of Depakote for maintenance treatment of bipolar disorder showed that it’s no better than placebo.  So why do doctors use it? Because it works (in the acute phase.)  Why do patients take it?  Again, because it works—oh, and their doctors tell them to continue taking it.  As the old saying goes, “if it ain’t broke, don’t fix it.”

However, what if it is broke[n]?  Some patients indeed fail Depakote monotherapy and require additional “adjunctive” medication (which, BTW, has provided another lucrative market for the atypical antipsychotics).  In such cases, most psychiatrists conclude that the patient’s disease is worsening and they add the second agent.  Might it be, however, that after the patient’s initial “response” to Depakote, the medication wasn’t doing anything at all?

To be sure, the Abilify study may have been more convincing if it was larger, followed patients for a longer time, and had a dedicated placebo arm consisting of patients who had not been on Abilify in the initial stage.  But I maintain that, regardless of the outcome of such an “improved” trial, most doctors would still use Abilify for maintenance treatment anyway, and convince themselves that it works—even if the medication is doing absolutely nothing to the underlying biology of the disease.

The bottom line is that it’s easy to criticize the FDA for approving a drug on the basis of a single, flawed study.  It’s also easy to criticize a pharmaceutical company for cutting corners and providing “flawed” data for FDA review.  But when it comes down to it, the real criticism should be directed at a field of medicine which endorses the “biological” treatment of a disorder (or group of disorders) whose biochemical basis and natural history are not fully understood, which creates post hoc explanations of its successes and failures based on that lack of understanding, and which is unwilling to look itself in the mirror and ask if it can do better.


The Placebo Effect: It Just Gets Better and Better

February 13, 2011

The placebo response is the bane of clinical research.  Placebos, by definition, are inert, inactive compounds that should have absolutely no effect on a patient’s symptoms, although they very frequently do.  Researchers compare new drugs to placebos so that any difference in outcome between drug and placebo can be attributed to the drug rather than to any unrelated factor.

In psychiatry, placebo effects are usually quite robust.  Trials of antidepressants, antianxiety medications, mood stabilizers, and other drugs typically show large placebo response rates.  A new paper by Bruce Kinon and his colleagues in this month’s Current Opinion in Psychiatry, however, reports that placebos are also show some improvement in schizophrenia.  Moreover, placebos seem to have become more effective over the last 20 years!

Now, if there’s any mental illness in which you would not expect to see a placebo response, its schizophrenia.  Other psychiatric disorders, one might argue, involve cognitions, beliefs, expectations, feelings, etc.—all of which could conceivably improve when a patient believes an intervention (yes, even a placebo pill) might make him feel better.  But schizophrenia, by definition, is characterized by a distorted sense of reality, impaired thought processes, an inability to grasp the differences between the external world and the contents of one’s mind, and, frequently, the presence of bizarre sensory phenomena that can only come from the aberrant firing of the schizophrenic’s neurons.  How could these symptoms, which almost surely arise from neurochemistry gone awry, respond to a sugar pill?

Yet respond they do.  And not only do subjects in clinical trials get better with placebo, but the placebo response has been steadily improving over the last 20 years!  Kinon and his colleagues summarized placebo response rates from various antipsychotic trials since 1993 and found a very clear and gradual improvement in scores over the last 15-20 years.

Very mysterious stuff.  Why would patients respond better to placebo today than in years past?  Well, as it turns out (and is explored in more detail in this article), the answer may lie not in the fact that schizophrenics are being magically cured by a placebo, but rather that they have greater expectations for improvement now than in the past (although this is hard to believe for schizophrenia), or that clinical researchers have greater incentives for including patients in trials and therefore inadequately screen their subjects.

In support of the latter argument, Kinon and his colleagues showed that in a recent antidepressant trial (in which some arbitrary minimum depression score was required for subjects to be included), researchers routinely rated their subjects as more depressed than the subjects rated themselves at the beginning of the trial—the “screening phase.”  Naturally, then, subjects showed greater improvement at the end of the trial, regardless of whether they received an antidepressant or placebo.

A more cynical argument for why antipsychotic drugs don’t “separate from placebo” is because they really aren’t that much better than placebo (for an excellent series of posts deconstructing the trials that led to FDA approval of Seroquel, and showing how results may have been “spun” in Seroquel’s favor, check out 1BoringOldMan).

This is an important topic that deserves much more attention.  Obviously, researchers and pharmaceutical companies want their drugs to look as good as possible, and want placebo responses to be nil (or worse than nil).  In fact, Kinon and his colleagues are all employees of Eli Lilly, manufacturer of Zyprexa and other drugs they’d like to bring to market, so they have a clear interest in this phenomenon.

Maybe researchers do “pad” their studies to include as many patients as they can, including some whose symptoms are not severe.  Maybe new antipsychotics aren’t as effective as we’d like to believe them to be.  Or maybe schizophrenics really do respond to a “placebo effect” the same way a depressed person might feel better simply by thinking they’re taking a drug that will help.  Each of these is a plausible explanation.

For me, however, a much bigger question arises: what exactly are we doing when we evaluate a schizophrenic patient and prescribe an antipsychotic?  When I see a patient whom I think may be psychotic, do I (unconsciously) ask questions that lead me to that diagnosis?  Do I look for symptoms that may not exist?  Does it make sense for me to prescribe an antipsychotic when a placebo might do just as well?  (See my previous post on the “conscious” placebo effect.)  If a patient “responds” to a drug, why am I (and the patient) so quick to attribute it to the effect of the medication?

I’m glad that pharmaceutical companies are paying attention to this issue and developing ways to tackle these questions.  Unfortunately, because their underlying goal is to make a drug that looks as different from placebo as possible (to satisfy the shareholders, you know) I question whether their solutions will be ideal.  As with everything in medicine, though, it’s the clinician’s responsibility to evaluate the studies critically—and to evaluate their own patients’ responses to treatment in an unbiased fashion—and not to give credit where credit isn’t due.

“That’s OK, I Didn’t Need That Brain Anyway”

February 10, 2011

Long-term treatment with antipsychotic medication apparently causes a decrease in brain volume, according to a new report by Nancy Andreasen’s group at the University of Iowa in this month’s Archives of General Psychiatry. In the study, over 200 schizophrenic patients, treated with antipsychotics, underwent MRI scans of their brains at various intervals over a 5-14 year period. The results showed that the “intensity” of antipsychotic treatment (i.e., doses and lengths of treatment) correlated with the reduction in brain tissue.

Instead of just looking at an overall “snapshot” of the brain, researchers calculated the volumes of several brain regions (from the whole-brain MRI scans) and found, on average, subtle decreases in both gray matter and white matter volumes, as well as enlargement of the ventricles (the “spaces” in the normal brain). The changes were more pronounced with longer time periods of treatment and, in particular, when higher doses of antipsychotics were used for extended periods of time.

As expected, this finding has generated a great deal of interest— if not concern– and more than a touch of “I-told-you-so” from certain camps (see “Antipsychotics Shrink the Brain” by Robert Whitaker). Indeed, at first blush, it is quite shocking to think that the first-line treatment for such a devastating brain disease might cause damage to the very organ we are trying to treat.

But is it really “damage”? All joking aside, I think the title of this post needs to be taken seriously. Does the observed loss in brain tissue loss mean that a person is incapacitated in any way? That he can no longer think, feel, see, taste, or make plans for the future? Moreover, despite the headlines, the tissue loss was not incredibly dramatic. In other words, we’re not talking about a healthy, robust brain turning into a moth-eaten mass of Swiss cheese. In fact, by my read of the data, the largest individual change in frontal gray matter volume was from about 330 cm3 to 290 cm3 over a 10-year period (yes, that’s >10%, but who knows what else was happening in that patient?). Other changes were much smaller, and many patients actually showed increases in brain volumes.

There were slight correlations with disease severity (more symptomatic disease was associated with a greater decrease in brain volume), and different classes of antipsychotics affected some regions of the brain differently than others. Interestingly, there seemed to be no independent effect of substance abuse on brain volume changes, despite the oft-heard warning that drugs and alcohol “kill brain cells.”

So what does this all mean? Obviously, some will say that this provides evidence that antipsychotics are toxic to brain cells. But there’s no clear evidence that neurons are actually dying; in some studies in monkeys taking antipsychotic medication, the number of neurons remains constant, but they increase in density because support cells (called glia) decrease in number– resulting in the macroscopic appearance of a “smaller brain.”

Moreover, it is quite possible that the disease process itself already leads to a decrease in brain volume (actually, we know this already) and effective treatment helps to further “prune” dysfunctional areas of the brain. In fact, an editorial accompanying the article claims that “strategic reductions in brain volume” might actually be therapeutic, and reminds us that gray matter volume decreases significantly during human adolescence, a process thought to underlie the organization and refinement of brain cells, and elimination of redundancy. (No wonder you have to tell your teenage son six times to clean his room.)

The best way to tackle this question, of course, is to take two groups of schizophrenics, treat one “as usual” with antipsychotics and the other with no medication at all, and perform brain scans at regular intervals. For ethical reasons, we can’t do this (it’s unethical not to treat a psychotic patient with an antipsychotic– although some would argue differently). Another way is to take advantage of the fact that many non-schizophrenic patients are now taking antipsychotics for OTHER diagnoses– bipolar disorder, depression, anxiety, insomnia, PTSD (just to name a few)– and we could compare those on antipsychotics to those on other drugs. If we see brain tissue loss across a wide spectrum of diagnoses, it suggests that this effect may be a direct result of antipsychotic treatment, even though the mechanism remains unknown.

Regardless of what’s actually happening in the brains of treated schizophrenics– and whether it’s “good” or “bad,” or whether it resembles the brain loss observed in birds living near Chernobyl— two things must be kept in mind. First, the patient’s well-being is of utmost importance; it would be inappropriate to withhold antipsychotic treatment from a patient who is clearly tormented and disabled from his paranoia, his delusional preoccupations, and his absolute lack of insight, particularly when we know that such medications do, in most cases, result in dramatic improvement. At the same time, we must also consider the other side of the coin, namely that if antipsychotics might cause an unexplained loss in brain tissue—or any other anatomic defect elsewhere, for that matter—we must seriously consider our rationale for these drugs. In particular, brain development in children is an ongoing process, not complete until late adolescence or early adulthood.

Hopefully this finding will stimulate research to determine how antipsychotics affect brain cells over time. Perhaps then we can find ways to preserve brain structure – or, at least, essential brain structure—while still treating the symptoms of mental illness. In other words, avoiding harm, while still doing good.

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