Dietary Sugar and Mental Illness: A Surprising Link

Noted British psychiatric researcher Malcolm Peet has conducted a provocative cross-cultural analysis of the relationship between diet and mental illness. His primary finding may surprise you: There is a strong link between high sugar consumption and the risk of both depression and schizophrenia.

In fact, there are two known mechanisms through which sugar intake could exert a toxic effect on mental health.

First, eating sugar actually suppresses the activity of a key growth hormone in the brain called BDNF. This hormone promotes the health and maintenance of neurons in the brain, and it plays a vital role in memory function by triggering the growth of new connections between neurons. BDNF levels are critically low in both depression and schizophrenia, which explains why both syndromes often lead to shrinkage of key brain regions over time (yes, chronic depression actually leads to brain damage). There's also evidence from animal models that low BDNF can trigger depression.

Second, sugar consumption triggers a cascade of chemical reactions in the body that promote chronic inflammation. Now, under certain circumstances (like when your body needs to heal a bug bite), a little inflammation can be a good thing, since it can increase immune activity and blood flow to a wound. But in the long term, inflammation is a big problem. It disrupts the normal functioning of the immune system, and wreaks havoc on the brain.

Inflammation is associated with an increased risk of heart disease, diabetes, and cancer . . . and also linked to a much greater risk of depression and schizophrenia. And again, eating sugar triggers inflammation. So does eating ubiquitous processed sugars like 'high fructose corn syrup'.

If you think about it, it makes sense that our bodies don't handle sugar very well. After all, for the vast majority (99.9%) of our existence as a species, there simply was no sugar. We were endowed with a sweet tooth so that we'd crave the highly nutritious fruits that were in rare supply in the ancestral environment. But with the advent of processed sugar cane a few centuries ago, the blessing of our formerly adaptive sweet tooth suddenly turned into a curse - causing us to crave foods that we were simply never designed to process.

As I've become increasingly convinced by these research data, I've begun gently encouraging my depressed patients to simply try cutting out sugars for a week to see if they notice any effect. (I also ask them to cut out simple starches - like crackers and white bread - which the body converts directly to sugars). Many patients have given it a go . . . often with rather remarkable improvements in mood, energy level, and mental clarity.

And, even though I've been very fortunate to escape the debilitating scourge of depression, I tried cutting out sugar myself a few months ago. Although one can never rule out placebo effects in such self-directed trials (!) . . . I've definitely noticed a nice improvement in energy and mental sharpness (I used to get a little foggy for an hour or two after lunch, and that just doesn't happen any more).

If you decide to give it a try, please be sure to pass along the results under the blog's Comments section. Good luck!

Social Isolation: A Modern Plague

The latest research confirms it: Americans are now perilously isolated. In a comprehensive new study by scientists at Duke University (Psych Pundit's alma mater), researchers have observed a sharp decline in our social connectedness over the past 20 years.

Remarkably, 25% of all Americans are now completely alone - without a single person they can confide in. And over half of all Americans report having no close confidants or friends outside their immediate family. The situation today is much worse today than it was when similar data were gathered in 1985 (when, for example, only 10% of Americans were completely alone).

How could this happen? It's hundreds of little things. You can probably think of several off the top of your head: longer work hours, surfing the Internet, tuning out the world as you march along to the isolating beat of your iPod . . . and don't forget all that time stuck in traffic.

According to Robert Putnam, sociologist and author of the influential book, Bowling Alone, for every 10 minutes added to your commute time, there's a 10% decrease in the likelihood of maintaining social ties.

But we're truly not designed to live like this. For the vast majority of human history, everyone lived in intimate, hunter-gatherer communities of 100-150 people. Anthropologists who spend time with modern-day hunter-gatherer bands report that social isolation and loneliness are competely unknown . . . as people spend virtually all day every day in the company of friends and loved ones.

Even Americans of a couple generations ago used to benefit from a richness of community life that has slowly disappeared. We've witnessed a long slow retreat into the hermetically sealed existence of our own fortress-like homes . . . friendships replaced by computer screens, Netflix videos, and exhausted couch potato stupor.

The toll? Increased vulnerability to mental illness. Social isolation is a huge risk factor for the onset of depression. There's also growing evidence that isolation increases vulnerability to various forms of addiction. I'll discuss this more in a future post . . .

Blogging Is Hard Work

My apologies, Dear Reader, for this lengthy hiatus from the blogosphere. Academic duties have been all-consuming these past few months, but I've thought wistfully on many occasions about the need to return with more Punditry. Now that summer is upon us, there should be ample time to make it happen.

Stay tuned . . .

A Profound Threshold

What is the most powerful computational device on the planet? If you answered "the human brain" you would have been right . . . until a few months ago.

As you may know, the brain is exquisitely designed to process information. Its array of 100 billion neurons, interconnected in a lattice of 100 trillion synapses (connections), is capable of processing an estimated 100 trillion pieces of information every second. This is an unfathomably large amount of computation.

When I took a computer class back in college in the 1980s, no man-made computer could even come close to that sort of processing capacity. Not even one millionth as much! It was impossible to believe that a computer could ever come close to rivaling our cerebral 'hardware'. But I remember one of my professors telling us to watch out for Moore's Law - which states that computer processing speeds double every 12 months or so. Due to inexorable technology advances, computers just keep on getting faster and more powerful, with no foreseeable end in sight.

As a result, the world crossed a remarkable threshold last year . . .

For the first time in history, the human brain was supplanted as the most powerful computer on earth. That distinction is now held by an IBM supercomputer known as Blue-Gene/L, which clocked in this past October at an astonishing 280 trillion operations per second. It has about three times more processing capacity than the human brain! (Sadly, it's being used by Livermore Laboratories to help develop our nuclear arsenal - your tax dollars at work.)

Does that mean that computers will soon be exhibiting superhuman intelligence? Well, in some ways, of course, they already are. Gary Kasparov, the best chess player in history, can no longer beat the best computer chess programs.

But it will still be many years before computers are able to accomplish several of the computational feats that we take for granted. The ability to understand and generate language looks like it will be the toughest 'artificial intelligence' problem - and computers at present are nowhere close to being able to do this. Mostly it's because artificial intelligence researchers and programmers usually don't have super-powerful computers at their disposal . . . most of them use the same desktop PCs that you and I do, which means they have less than 1/100,000th of the processing power of a human brain.

This will change in the decades ahead, however. Because of Moore's Law, it's fairly safe to assume that a good desktop PC in the year 2020 will have about the processing power of a human brain . . . enough to do a creditable job simulating human language.

While there is certainly much to be concerned about with such developments, in some future post I'll discuss some of the potentially positive implications regarding our understanding and treatment of mental illness.

Antidepressants in the Real World

First, kudos to ns, who was right on the money about the median length of time people stay on antidepressant medications (last week's 'challenge question'). According to a definitive study just published in the American Journal of Psychiatry, about half of all patients stop taking their meds within the first month.

This is a big problem, for a number of reasons:

(1) The vast majority of depressed patients will not achieve full recovery after just one month of treatment, and incomplete recovery is a huge risk factor for the recurrence of full-blown depression. Sadly, depression will return again eventually for 70-80% of all treated depressed patients - and that risk level actually goes up for those who terminate treatment before they're fully recovered.

(2) Because it's routine practice to prescribe antidepressants for at least 4-6 months (often much longer), it's safe to assume that most patients are discontinuing meds against medical advice. In other words, they're just stopping abruptly on their own. Unfortunately, most antidepressant meds have a well-defined withdrawal syndrome - which can include dizziness, nausea, headaches, lethargy, agitation, irritability, and even "electric" shock-like sensations in the head or limbs. Quitting these meds abruptly - without a doctor's supervision - can increase the chances of having these horrible withdrawal effects.

(3) The short-term 'cure rate' of antidepressants is low enough as it is - as low as 28% in the largest study published to date. And that's for the people who actually stay on the meds as prescribed . . . which means that the true cure rate in the real world is considerably lower, given how many patients discontinue treatment early.

But why would so many people stop taking their meds against the advice of their doctor? Although cost may be a factor in a small number of cases, in my clinical experience it's the nasty side effects that are usually the culprit. Sexual side effects - including an inability to experience orgasm and decreased libido - are quite common, especially in the SSRI class of meds that includes best-sellers like Zolft, Celexa, Lexapro, Prozac, and Paxil. Less talked about, but equally common, is the phenomeonon of 'emotional numbing' - a reduced intensity of negative emotions like sadness and anxiety, but also the blunting of positive emotions like joy and excitement (the movie Garden State did a nice job of portraying this phenemenon).

So, although they are truly a godsend for some, antidepressants don't represent a lasting cure for the majority of depressed individuals. Fortunately, there are other treatment options that look more promising for long-term success in the battle against depression, among them: aerobic exercise, omega-3 supplementation, behavioral activation, and interpersonal psychotherapy. I'll plan to elaborate on these in an upcoming post.

Returning Soon With More Punditry

Dear Readers:

I'm afraid I got swamped again with academic deadlines over the past couple weeks, but will be back with timely posts and lots of fresh material in the days ahead.

Thanks for your patience!


In the meantime, a challenge question . . .

What is the average length of time a patient on antidepressants actually stays on their meds? [Hint: The answer is published in the January issue of American Journal of Psychiatry]

The Dark Side

Dan, my old college roommate, offers this interesting post on the Jungian concept of the shadow. It makes for provocative reading! Here's a short excerpt to whet your appetite:

The shadow is a moral problem that challenges the whole personality, for no one can become conscious of the shadow without considerable moral effort. To become conscious of it involves recognizing the dark aspects of the personality as present and real. This act is the essential condition for any kind of self-knowledge. (Aion, 1951, in Collected Works 9, Part II, p. 14)

The Mind-Body Problem

What are the most common - and most damaging - myths about mental illness out there? Every semester I collect 'reflection papers' from the 300 undergrads in my courses, so I've developed a pretty good inventory of these myths over the years. You'd probably guess many of them . . . things like:

"Depressed people could just 'snap out of it' if they really wanted to";

"Schizophrenic patients have multiple personalities";

"If you have an eating disorder, you were probably sexually abused".

There are dozens more that come quickly to mind. Maybe I'll do a whole post on it some day. But if I had to nominate the one myth that's the most widespread and damaging in its influence, I think I might pick the "myth of mind-body dualism".

This is the idea that the mind and the body (brain) are completely different entities, made of completely different 'stuff'. It's an idea with an impressive pedigree (luminaries like Plato and Descartes), but that's not why most people believe it. No, it's believed because dualism just seems so obviously true. After all, it feels for all the world like there's a completely non-physical self inside - thinking and feeling and acting on its own, regardless of what the rest of the body is up to.

Anthropologists tell us that remote people groups all over the world are mind-body dualists. They've yet to encounter a clan, band, or tribe that's not. Likewise, researchers have found that children are natural born dualists - making claims about non-physical minds as early as age 4-5.

But science, of course, is about discovering things that aren't obvious. Sometimes it means discovering that our most obvious intuitions are dead wrong:

It feels for all the world like the sun revolves around the earth, and for thousands of years everyone just assumed it did. It seems perfectly obvious that light can't be both a wave and a stream of particles at the same time, but it is. It seems obvious that living things have to be animated by some essence of life (elan vital) that's fundamentally different from non-living chemicals, but we know now that it's not.

Likewise, we know from neuroscience that the mind is what the brain does. In fact, the mind and the brain are flip sides of the same underlying reality.

This means anything that changes your brain also changes your mind. But perhaps more importantly - it means anything that changes your mind also changes your brain.

If, as a psychologist, I can help change a patient's thoughts, I've also (by definition) helped change his brain. Changing behavior changes the brain. Changing feelings changes the brain.

In a nutshell: experience changes the brain.

Why is this important? Because when it comes to mental illness, so many people automatically assume, "Oh, well the doctor said I probably have a 'chemical imbalance' or something wrong with my brain, so that means I have to take drugs to fix it." But if we understand that experience changes the brain - that the mind and brain are flip sides of the same underlying reality - we won't make this logical error.

In most cases, so-called 'chemical imbalance' may be just as readily cured by a healing experience as by a healing chemical.

The Doctor Is: Out

Alas, I'm swamped with academic duties (and a book deadline) at the start of a new semester, so it will be a few days before I can post another article.

In the meantime, I'm trying to talk Dan, erstwhile psychology major and my old college roommate, into writing a post for the Psych Pundit blog.

In one of life's little ironies, I never took an undergrad psych class (math major, believe it or not) but wound up as a psychology professor, while Dan - the psych major - now works as an attorney doing business valuation (lots of math stuff). Back in college, I used to tease Dan about the 'bogus' nature of psychology, so maybe god's got an interesting sense of humor . . .

As Good As It Gets?

I got a call from a psychiatrist colleague of mine a few years ago. He was an old-school Freudian psychoanalyst who had his patients come in twice a week to lie back on a couch, talk about their dreams, and free-associate about their early childhood experiences. Although this type of treatment may be useful for some patients - especially those who wish to better understand and change troublesome personality patterns - it has not been very strongly supported by research.

As it turned out, the psychiatrist was calling to ask if I would take on one of his patients who suffered from obsessive-compulsive disorder (OCD) - a debilitating mental illness that afflicts about 2% of the population (it was the disorder depicted by Jack Nicholson in the film, As Good As It Gets). The psychiatrist had already been treating this distraught young man for over 4 years, but his OCD symptoms had actually worsened over that span of time. Since there's no scientific evidence Freudian psychoanalysis can successfully treat OCD, I was willing to have the case transferred to my care.

Fortunately, during my grad school training at Duke, I had a set of instructors and supervisors who emphasized the importance of asking, for each form of mental illness: which of the hundreds of possible treatments for this disorder is the one most strongly supported by the research evidence?

For OCD, this is a no-brainer: a form of behavior therapy called exposure and ritual prevention has outperformed every other treatment (including meds) in every large-scale outcome trial ever published.

To get some idea of the potency of behavior therapy for OCD, consider the results of the largest OCD treatment outcome study to date sponsored by the National Institutes of Mental Health. The study pitted behavior therapy against a drug called Anafranil (clomiprimine), the most effective OCD medication currently on the market. Here were the results:

Behavior Therapy: 86% recovered
Anafranil: 48% recovered
Placebo: 10% recovered

As you can see, OCD is such a severe disorder that it has a minimal placebo response . . . it takes much more than placebo-induced positive expectancies to cure this particular illness. And even though the drug certainly beats the placebo (48% to 10%), it's obvious that behavior therapy is the treatment of choice (with a whopping 86% cure rate). In fact, it's not even a close call!

There's a genuine tragedy, though, embedded in these numbers . . . for the vast majority of OCD patients will never even know that behavior therapy exists. While some will waste their time and money on ineffective forms of psychotherapy, most OCD patients will simply be told that they have a 'chemical imbalance', handed a prescription of Anafranil or a similar medication, and told in effect, "this is as good as it gets". Obviously, it's not!

Sadly, it's so hard to get the word out about behavior therapy for OCD. Few mental health reporters understand the field well enough to do the story. Drug companies (as I've mentioned before) have multibillion dollar budgets to promote their products - for better and for worse - whereas psychotherapists skilled in behavior therapy for OCD are small in both numbers and financial resources. (To find such a therapist near you, try contacting the Center for Anxiety and Related Disorders.)

Oh, in case you're wondering . . . within 4 months of my taking on that OCD patient and treating him with standard behavior therapy, his symptoms were in complete remission. I've seen it repeatedly over the course of my career, and I'm not even a particularly gifted therapist (research is my main gig), nor is OCD my area of specialty.

So lately, whenever I see one of those silly Zoloft commercials (the ones with the sad little chemically imbalanced ovoid creatures), I find myself thinking, "If only someone had the money for a series of slick prime time commercials about behavior therapy. We've got to find a way to tell the 6 million OCD sufferers that there's a better treatment out there - one (alas) they've never even heard of."

On 'Chemical Imbalance'

Drug companies spend billions of dollars each year advertising their products. In fact, according to a brilliant expose of the pharmaceutical industry by Dr. Marcia Angell (former editor of The New England Journal of Medicine), drug companies spend about 3 times as much on marketing as they do on research and development!

And they've hit on a particularly effective marketing angle for their profitable line of antidepressant meds: it's all about 'chemical imbalance'. Just tell people they have a brain-related 'chemical imbalance', and most will assume it's a condition that can only be remedied by ingesting more chemicals (i.e., by taking expensive medications).

But this widespread assumption is flawed in its underlying logic. Simply put: medication is not the only way to change the depressed brain. Psychotherapy changes the brain. Pill placebo changes the brain. Exercise changes the brain.

Let's look at this last point in a little more detail. One of the most serious consequences of depression is the fact that it suppresses a key growth hormone in the brain (it's called BDNF, or brain-derived neurotrophin factor). Without adequate levels of this growth hormone, we can't form new connections between neurons, and those new connections are crucial to our ability to form new memories (this is the reason, in fact, that most depressed patients experience poor short-term memory). Over time, low levels of this growth hormone cause key regions of the brain to shrink. That's right: over time, depression causes brain damage.

But when we get aerobic exercise, this triggers a massive increase in the brain's production of neural growth hormone (BDNF). Not only does exercise help protect the depressed brain from damage, but it serves as a powerful antidepressant activity in its own right.

In a landmark study at Duke Medical Center, aerobic exercise (just 3 times per week for 30 minutes) was found to be as effective as Zoloft in the short term, and even more effective than Zoloft in the long-term treatment of depression.

Exercise is a potent treatment for depression. This is why the British Medical Association (a group much less influenced by the drug industry than our own American Medical Association) recently recommended exercise over antidepressant meds as a first-line treatment for depressive illness. The Brits now seem to understand what most Americans do not: chemical imbalance can be remedied by experience, not just medication.

Got Placebo?

It was just over 3 years ago, and reporters breathlessly heralded the news: "St. John's Wort Is Ineffective For Depression". Unfortunately, they got the story wrong, and missed the real story sitting right under their noses.

Here's what happened. The National Institutes of Health had just sponsored a large outcome study in which hundreds of depressed patients were randomly assigned to one of three treatment conditions: Zoloft (the best-selling antidepressant), St. John's Wort, or Placebo (an inert sugar pill). None of the treatments worked particularly well. After 8 weeks, the following proportions of patients were found to be recovered within each treatment group:

Placebo - 32%
Zoloft - 25%
St. John's Wort - 24%

Notice anything interesting? Yes, oddly enough, the sugar pill yielded the best results of all.(Statistically speaking, though, the 3 treatments were judged to be in a virtual tie.) Now, in order for medical researchers to conclude that any given drug is effective, it has to outperform a placebo control condition. Clearly, this didn't happen for St. John's Wort (hence the headlines) . . . but it didn't happen for Zoloft either (a fact that was completely ignored by the press)!

However, at this point, perhaps you're thinking, "Surely this study is some sort of anomaly. A fluke outcome. We already know that Zoloft and similar drugs are much more effective than a sugar pill." But do we?

Clinical researcher Irving Kirsch and his colleagues recently petitioned the Food and Drug Administration under the Freedom of Information Act for data on the 47 drug trials submitted by the pharmaceutical industry in their quest to get FDA approval for 6 of the most popular antidepressant medications (Prozac, Paxil, Zoloft, Celexa, Effexor, and Serzone). Most of these drug studies had never even been published, as drug companies tend only to publish the studies that show their drugs in a favorable light . . . but the FDA keeps permanent records of every such trial.

What did the FDA records show? Remarkably, Kirsch and colleagues found that in the majority of these drug trials, the antidepressant did not beat the placebo. In fact, when the researchers averaged across all 47 studies, they found that the placebo led to symptom reduction that was fully 85% as large as that of the active medications. This amounted to a 2-point average difference on a 52-point symptom rating scale; this magnitude of difference is not considered to be clinically significant.

Does this mean that Zoloft and similar drugs don't work? No. It's clear that they lead to complete remission for about 1/3 of the patients who take them (and to some improvement for many others) . . . It's just that much of this benefit for many patients is based on the placebo effect. The data on this point are crystal clear.

And how does the placebo effect work? This will be the subject of an upcoming post . . .

How Effective Are Antidepressants?

A growing body of scientific evidence suggests that antidepressant drugs are only modestly effective, probably much less so than you realize. Unfortunately, these medications just don't live up to the hype.

An eagerly awaited landmark study published in the American Journal of Psychiatry this week makes the point quite clearly. Researchers followed 2,876 depressed patients at 41 different clinics while they were treated with Celexa (citalopram) - one of the best-selling depression medications, and a close chemical cousin of drugs like Zoloft, Prozac, Paxil, and Lexapro.

According to researchers, after 10 weeks of treatment:

Remission rates were 28% [based on clinicians' ratings] and 33% [based on patients' ratings].

This means that fewer than 1 in 3 patients recovered on Celexa, regardless of whether we look at the patients' own ratings of their symptoms or those of their clinicians.

It gets worse.

Patients in this study got much better care than the vast majority of patients "in the real world." They saw their doctors every couple of weeks - much more frequently than almost any insurance plan will cover. Their doctors also carefully evaluated medication levels at each visit, and increased dosage if the meds didn't seem to be producing an adequate response at the initial dose (again, this doesn't happen as efficiently in real world settings). Thus, by the end of the treatment period, the average dose was about 50mg per day - a higher dose than most patients will ever take (typical starting dose is 20mg).

Finally, the study's 28% response rate is actually an over-estimate, since it excludes the many patients who quit taking the meds right away (i.e., before they completed their first followup evaluation) as well as those who were switched by their doctors to a different drug for any reason (e.g., intolerable side effects).

Bottom line: The great majority of patients who take antidepressant medications do not experience a complete and lasting cure of their depression. This is why, for example, the epidemic of depression in the U.S. keeps getting worse (the lifetime prevalence of depressive illness is now nearly 25%) despite the millions of prescriptions dispensed each week.

I truly wish it were otherwise. And if you happen to be one of those who have benefited enormously from taking an antidepressant medication (as a practicing clinician, I've seen many), then know that I rejoice with you . . . if only it happened more often.

In posts to follow, I'll discuss what the research literature has to say about more effective and enduring treatments for depression.