Tuesday, March 24, 2009

Which came first...

...the over-protective mother or the anxious child?

According to a new study from the Journal of Clinical Child & Adolescent Psychology, over-protective mothering appears to be a "natural response" to anxious children.

The researchers, led by Jennifer Hudson of Macquarie University, knew from previous researchers that the mothers of anxious children tended to be over-protective and over-involved. What they didn't know, said Hudson, was "whether it is the child's anxiety that brings out over protective behavior."

For this study, titled "Child and Maternal Influence on Parenting Behavior in Clinically Anxious Children," the researchers compared clinically anxious children to their non-anxious counterparts as they interacted with mothers not their own. Hudson's group found that "when mothers interacted with an anxious child, they provided significantly more help to the child than mothers interacting with a child who did not have an anxiety disorder. "

"These results suggest that over-protection is a normal response to an anxious child and not the fault of the mother," Hudson said. "These findings may help reduce parental feelings of guilt and blame and may help parents understand their own and their child's behavior."

Many mothers of eating disordered children are accused of being over-protective, and many eating disordered children also show pre-morbid anxiety traits or disorders. This indicates that mothers of ED'd children may perhaps be more over-protective but that this is not necessarily indicative of any pathology on the mother's behalf. It's just a natural response to an anxious child.

Thursday, March 19, 2009

Hypermetabolism: the basics

Many people recovering from AN experience hypermetabolism, a common phenomenon that is often overlooked. I did some more research tonight into the biology and etiology of hypermetabolism. So let's start with a basic definition from Wikipedia:

Hypermetabolism is the physiological state of increased rate of metabolic activity. The impact of the hypermetabolic state on patient nutritional requirements is often understated or overlooked. Hypermetabolism typically occurs after significant insult to the body. In hospitals and institutions, the most common causes are infections, sepsis, burns, multiple trauma, fever, long-bone fractures, hyperthyroidism, prolonged steroid therapy, surgery and bone marrow transplants.

And, yes, eating disorders. Specifically anorexia. As someone falls deeper and deeper into anorexia, their metabolic rate slows dramatically. During the Minnesota Starvation Study, resting energy expenditure (also known as basal metabolic rate- the amount of calories needed just to keep your body functioning and doesn't include ANY physical activity) fell by about one-third. The book "Introduction to Clinical Nutrition" says that

Starvation involves metabolic alterations that enhance the chance of survival by increasing the use of body fat stores, by sparing the use of glucose, by minimizing nitrogen loss, and by decreasing energy expenditure.

But when the ill person begins eating again, their metabolism kicks into high gear. Body temperature rises. A person can experience night sweats, which may also be related to hormone function returning to normal. Why? It seems a remarkably inefficient use of resources. And indeed, hypermetabolism may not be entirely adaptive from an evolutionary standpoint as the body's use of food becomes remarkably inefficient. Even so, the body needs tremendous amounts of energy to replace lost fat and muscles stores, depleted organs, bone mass, hair, nails, you name it. No organ system is spared during an eating disorder.

The amount of calories needed for people with anorexia to return to a healthy weight can vary by illness severity (a lower BMI means more calories, as well as duration of illness), and by illness subtype. One study found that those with the binge-purge subtype of anorexia needed significantly fewer calories than those with the restricting subtype; another study found that calories were about the same. Other variants include your metabolic rate before illness onset. I've known several good friends curse their fast metabolisms quire vociferously during refeeing.

When looking at the phase after weight restoration, caloric needs between people with anorexia nervosa and those with bulimia nervosa turn out to be quite different. One study found that people with AN needed more calories per kilogram of body weight than normal controls, while those with BN needed fewer. It appears that people with a current diagnoses of BN but a history of AN require more calories than those with BN alone. Further, people with the restricting type of AN needed more calories than those with the binge-purge type, both of which were greater than patients with BN (some of the studies cited above show that, for weight maintenance, caloric needs are basically the same for any patient with a current diagnosis of AN).

Some of these differences may rest in premorbid differences in metabolic rate. It makes intuitive sense that a person who finds it easy to lose weight would have a faster innate metabolism. Other reasons calorie needs may remain unusually high for a person even after weight restoration is the sheer amount of rebuilding the body needs to perform. Bulimia is violently destructive to the body, and I would never say differently. However, some of the damage done by anorexia is slightly different, and the body must rebuild and repair essentially every organ in the body. My psychiatrist told me that the nerves continue to repair themselves for up to two years after weight restoration. This can hardly be the only organ system taking a long time to recover.

How long hypermetabolism lasts will probably vary from person to person, and depends on how long you were sick, how your body responded to the damage from your eating disorder, your activity levels, among others. There's no real way to be sure. If your caloric needs are unusually high--even for hypermetabolism--you can have body composition analysis and resting energy expenditure testing done. Personally, I think this is best left to extreme cases since so many sufferers have a tendency to fixate on numbers.

I hope this helps explain hypermetabolism just a little bit. I can't answer every question, as it's been a long time since my college biochemistry days, but I can always look things up.

Cortisol and eating disorders

I was excited to see that my recent survey about sleep/wake habits here on the blog supported my hypothesis: that those with restrictive patterns tend to rise earlier, and those with more binge/purge patterns rise later. Of course, in order to really look at the data, I'd need to compare the early bird and night owl percentages of each category with those of a non-ED sample.

Although many things affect circadian rhythm--most of which are under genetic control--one of the key hormones is cortisol. Released from the adrenal cortex, cortisol levels generally peak upon waking and reach a low point shortly after you go to sleep. What's more, cortisol is released during times of stress or anxiety, increasing both blood pressure and blood sugar. A PubMed search of eating disorders and circadian rhythm produced mainly results on night eating syndrome. However, one study found a negative correlation between awakening cortisol response and "high anxiety, disinhibition and hunger scores, as well as poor body esteem and a high weight preoccupation" in women, but not men. That means that women with a low awakening cortisol response have high levels of anxiety, poor body esteem, etc. Of course, we don't know if this is cause or effect- just that it exists.

A study in men found a significant relationship between cortisol and perfectionism, which makes sense. Perfectionism is stressful (and don't I know that!), and higher stress means higher cortisol. As well, abnormalities in cortisol have been found in other psychiatric disorders, such as depression.

In otherwise healthy women who did not have regular menstrual periods, cortisol levels were increased compared to normal women, indicating stress on the body (the authors hypothesized that the reason for this amenorrhea was insufficient fat intake, despite sufficient calories and without excessive physical activity).

And indeed, women with anorexia were found not only to have higher cortisol levels but a significant proportion lacked a circadian cortisol rhythm. These abnormal cortisol levels are directly related to the starvation state- after weight restoration, cortisol levels return to normal. I'm not sure how the lack of cortisol rhythm is important. In general, starvation disturbs the sleep cycle, and refeeding is typically associated with improvements in sleep. The general school of thought is that the body is urging the starving person to go get food, and this may be true. But the high levels of cortisol brought out by the stress of malnutrition and starvation may also play a role. High cortisol levels in people with AN have been positively associated with both osteoporosis andhyperactivity.

Although one study found that overall daily cortisol rhythms in normal weight bulimic women were pretty much the same as in healthy women, another found evidence of greatly increased cortisol levels. It appears that, in bulimia, cortisol levels might be much higher than usual, although they still have a daily rhythm, unlike in anorexia. Even recovered bulimic patients continued to show a hyperreactivity to corticotropin-releasing hormone, which stimulates the release of cortisol, indicating an underlying neuroendocrine dysfunction.

Yet when cortisol levels were examined in relation to impulsivity, researchers found an inverse relationship between cortisol levels and impulsivity:

Patients with bulimic symptoms had significantly higher rates of cortisol suppression than controls and than restrictive anorectic patients. Percent cortisol suppression showed a strong and significant correlation with the patient's score on the Barratt Impulsiveness Scale. A hypersensitive cortisol response to dexamethasone, which might reflect hypothalamic-pituitary-adrenal axis dysfunctions might be specifically associated with impulsive subtypes of eating disorders.

Clearly, cortisol is just one player on a much larger field. Nor is it clear whether abnormalities in cortisol levels are cause or effect, and perhaps it's a little bit of either. Certainly the eating disorder exaggerates any underlying abnormalities. Whether the ED behaviors themselves cause the specific differences observed in cortisol levels in anorexia and bulimia, or whether these differences are part of the underlying risk factors for these illnesses also remains unclear.

(originally posted at ED Bites)

Long time, no write

Hi everyone.

My apologies for not writing recently- I had just started a new job in Washington, DC and was trying to move and get all my stuff organized. As well, I did some freelance writing that culminated in a Washington Post article on the Maudsley Method titled "A girl's suffering drove her parents to try a new anorexia treatment."

I do have several topics in the pipeline. However, there are one or two posts from my other blog ED Bites that might be of interest to parents, so I'm reposting them here. The first one is on hypermetabolism. The second is on cortisol and EDs.

Happy reading everyone!