Friday, May 27, 2016

Understanding Brain Development Across The Life Cycle To Improve Treatment For Young Patients

Reprinted from Eating Disorders Review
May/June Volume 27, Number 3
©2016 IAEDP
Better understanding of neuro-development and the concept of brain development across the life cycle can help clinicians improve treatment of teens and young adults, according to Dr. Scott E. Moseman, Medical Director, and Leah Graves, RDN, Nutrition Therapy Manager, at the Laureate Eating Disorders Program, Tulsa, OK. 
Dr. Moseman told symposium attendees that dividing eating disorders into traits and states can be helpful for understanding the development and maintenance of eating disorders among young patients. Underlying traits are genetically determined and affected by hormonal, developmental, and environmental pressures that eventually lead to illness. The illness is then sustained by intrinsic and environmental states.

Traits leading to risk

Temperament and personality traits that lead to anorexia are well known, including anxiety, negative emotionality and low self-esteem, along with low reactivity to reward, and harm avoidance. Some of the same traits, including negative emotionality and low self-esteem, can put an individual at risk of developing bulimia. The internal and external influences that promote risk include normal changes at puberty (estrogen changes that affect serotonin, corticotropin-releasing hormone [CRH], cortisol, and developmental changes in the frontal and limbic circuits), and body weight increase and distribution (due to leptin and ghrelin changes). Dr. Moseman added that during puberty, psychological and environmental influences activate, including “trauma and stress during sensitive periods to a sensitive brain.” Other elements include separation and individualization in a high-stress environment, coupled with a fat-phobic culture that holds up thinness as an ideal measure of success and that perpetuates high activity and low caloric intake.
Dr. Moseman said that several physiologic realities prevent anorexic patients from stopping their harmful behaviors. The anorexic patient’s brain, now malnourished, is state-dependent to continue the illness. Along with this is a regression to prepubertal gonadal function and excess limbic serotonin. One more element is that starvation causes increased excretion of CRH, leading to dysphoria, hyperactivity, and decreased feeding. 
Serotonin’s role in perpetuating anorexia has become clearer, too, he noted. With dieting, serotonin decreases, improving mood. Then, weight loss decreases CRH, worsening mood, which leads to dieting, and improved mood. For bulimic patients, there is a disconnect between ideal body image and urges to eat. Bulimics get positive reinforcement from stopping harmful behaviors, and this reduces dysphoria. However, the neurobiological model of intermittent excessive behavior may then come into play; this is behavior common to binge eating, drug abuse, alcoholism, and excessive gambling. Dopamine-related systems also power excessive eating.

Age and drug effectiveness

A patient’s age has much to do with the effectiveness of pharmacotherapy, according to Dr. Moseman. For example, he explained that most psychotropic agents act through neurotransmitters such as dopamine, serotonin, and norepinephrine, and their receptors undergo major changes during normal physical development. Receptor density peaks in the preschool years and then gradually declines toward adult levels in the late teens. In the few studies that have been done, results have shown that stimulants are less likely to induce euphoria in children than in adults, while antipsychotics are more likely to produce metabolic effects in younger patients than in adults. Thus, the younger the patient, the lower the tolerance to stimulants. Perhaps the most controversial example is the use of SSRIs and risk of suicide, he said.

Nutritional considerations

Dietitian Leah Graves told attendees that nutritional intervention is essential for healing and for helping patients get back on track with normal growth and development. Puberty brings significant increases in height, weight, bone mass, body composition, and sexual maturation, making nutritional needs greater at this time than at any other stage of development--other than the first year of life. For females, a linear growth spurt occurs prior to menarche and 15% to 25% of final adult height is often reached by menarche. Growth spurt begins later in males, who often gain 2 to 5 inches in height per year. Half of adult weight is gained during puberty, and 50% of bone mass and peak bone mass are reached during adolescence. By the age of 18 most teens have accumulated 90% of their bone mass. 
Graves told the audience that when an eating disorder occurs, food-related behaviors disrupt the availability of the essential energy, vitamins, and minerals needed for normal growth and development. Energy needs are high during these years; for males this can mean 3000 to 4000 kcal per day or more, and for females 2400 to 3000 or more per day. Patients need energy for healing in addition to the energy needed for normal growth and development. Those with restricting-type anorexia nervosa (AN-R) require more energy intake than do all other subgroup, while AN patients who have been obese require less energy in order to gain weight.

Some strategies to improve nutrition

According to Graves, two keys to improving nutrition among these patients are: (1) involving parents or caregivers in meals and (2)establishing a structured and consistent eating pattern for patients. Early weight gain is essential, and clinicians may find that their patients benefit from having fewer food choices at first. More recent studies have also suggested that younger patients tolerate a higher caloric load with larger incremental advances, such as 1500 to 1800 kcal/day, with subsequent daily increases of 120 to 200 kcal. Increased use of energy-dense foods may also improve outcome.
Later, patients can benefit from a variety of selections, including added fats, starchy carbohydrates, and caloric beverages. Graves described a newer approach to help patients deal with eating-related fears during weight restoration. Exposure and Response Prevention for AN (AN-EXRP) uses a technique first presented by Dr. Joanna Steinglass of Columbia University. This approach specifically addresses maladaptive eating behavior by targeting eating-related fears and anxiety during weight restoration (Int J Eat Disord. 2014. 47:174).
Graves advised addressing patients’ eating-related fears, and emphasized that weight restoration should be personalized, starting with the least-fear-producing foods and graduating to those that produce the most fear. When setting goal weights, it is also good to remember that a weight range is a moving target, she said, and should start where growth would be without the interference of the eating disorder. In this light it is helpful to determine an individual’s pattern of growth prior to the onset of his or her eating disorder. Weight expectations increase each year, to keep up with projected growth and development. This pattern is easier to explain to the patient with weight tables from the Centers for Disease Control and Prevention, Graves said. 

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