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The Effects of Acute Dopamine Precursor Depletion on the Reinforcing Value of Exercise in Anorexia Nervosa.

ABSTRACT: This study investigated whether dopaminergic systems are involved in the motivation to engage in behaviours associated with anorexia nervosa (AN), specifically, the drive to exercise. Women recovered from AN (AN REC, n = 17) and healthy controls (HC, n = 15) were recruited. The acute phenylalanine/tyrosine depletion (APTD) method was used to transiently decrease dopamine synthesis and transmission. The effect of dopamine precursor depletion on drive to exercise was measured using a progressive ratio (PR) exercise breakpoint task. Both groups worked for the opportunity to exercise, and, at baseline, PR breakpoint scores were higher in AN REC than HC. Compared to values on the experimental control session, APTD did not decrease PR breakpoint scores in AN REC, but significantly decreased scores in HC. These data show that women recovered from AN are more motivated to exercise than HC, although in both groups, activity is more reinforcing than inactivity. Importantly, decreasing dopamine does not reduce the motivation to exercise in people recovered from AN, but in contrast, does so in HC. It is proposed that in AN, drive to exercise develops into a behaviour that is largely independent of dopamine mediated reward processes and becomes dependent on cortico-striatal neurocircuitry that regulates automated, habit- or compulsive-like behaviours. These data strengthen the case for the involvement of reward, learning, habit, and dopaminergic systems in the aetiology of AN.

SUBMITTER: O'Hara CB

PROVIDER: S-EPMC4726788 | biostudies-literature | 2016

REPOSITORIES: biostudies-literature

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The Effects of Acute Dopamine Precursor Depletion on the Reinforcing Value of Exercise in Anorexia Nervosa.

O'Hara Caitlin B CB Keyes Alexandra A Renwick Bethany B Leyton Marco M Campbell Iain C IC Schmidt Ulrike U

PloS one 20160125 1

This study investigated whether dopaminergic systems are involved in the motivation to engage in behaviours associated with anorexia nervosa (AN), specifically, the drive to exercise. Women recovered from AN (AN REC, n = 17) and healthy controls (HC, n = 15) were recruited. The acute phenylalanine/tyrosine depletion (APTD) method was used to transiently decrease dopamine synthesis and transmission. The effect of dopamine precursor depletion on drive to exercise was measured using a progressive r ...[more]

PMID: 26808920

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Project description:"Hyperactivity" has a wide prevalence range of 31% to 80% in the anorexia nervosa literature that could be partly due to the plethora of definitions provided by researchers in this field. The purpose of this study was two-fold: 1) To assess the variance across prevalence rates of problematic exercise encountered in patients with anorexia nervosa, in relation to seven different definitions found in the literature. 2) To examine how core eating disorder symptoms and the dimensions of emotional profile are associated with these different definitions and the impact of these definitions on the assessment of patients' quality of life. Exercise was evaluated in terms of duration, intensity, type and compulsion using a semi-structured questionnaire administered to 180 women suffering from severe anorexia nervosa. Seven different definitions of problematic exercise were identified in the literature: three entailing a single dimension of problematic exercise (duration, compulsion or intensity) and four combining these different dimensions. Emotional profile scores, obsessive-compulsive symptoms, eating disorder symptomatology, worries and concerns about body shape, self-esteem and quality of life were assessed using several established questionnaires. The prevalence of problematic exercise varied considerably from, 5% to 54%, depending on the number of criteria used for its definition. The type and level of eating disorder symptomatology was found to be associated with several definitions of problematic exercise. Surprisingly, a better self-reported quality of life was found among problematic exercisers compared to non-problematic exercisers in three of the definitions. The different definitions of problematic exercise explain the broad prevalence ranges and the conflicting associations generally reported in the literature between problematic exercise and eating disorder-related psychological parameters. There is an urgent need for a valid consensus on the definition of problematic exercise in anorexia nervosa. This will support the development of further research on the etiology and treatment of problematic exercise.

Project description:BackgroundLong-term consequences of comorbid autism spectrum disorder (ASD) in individuals with anorexia nervosa (AN) are inadequately investigated.MethodsIn the 1980s, 51 adolescent-onset AN cases (AN group) and 51 matched controls (COMP group) were recruited from the community. They have been examined on five occasions. The four last assessments included the Morgan-Russell Outcome Assessment Schedule (MROAS) to assess eating disorder outcomes (weight, dieting, menstruation), and related problems including psychiatric, psychosexual and socioeconomic state. In the present study, at age 44, when 30 years had elapsed, MROAS data were compared with previous results. At age 16, 21, 24 and 32 years, all individuals had been assessed regarding ASD. At the 30-year follow-up, the impact of the ASD on the MROAS data was analysed.ResultsIn the AN group, all core anorectic symptoms (weight, dieting, menstruation) were on a par with the COMP group at the 30-year follow-up, but the positive outcomes were limited to those who had never had an ASD diagnosis. Psychiatric state was significantly worse in the AN group, particularly in the subgroup who had an ASD diagnosis assigned. The AN group-again particularly those with ASD-had a more negative attitude to sexual matters than the COMP group. The AN group had worse outcomes than the COMP group for 'personal contacts', 'social contacts,' and 'employment record' at the 30-year follow-up and the outcomes were worse the more often an ASD diagnosis had been assigned.LimitationsRare data collection points throughout 30 years (only 5 assessments). ASD was assessed in the first four studies but was not assessed again at the 30-year follow-up.ConclusionsMental health, psychosexual, and socioeconomic status were compromised up to 30 years after AN onset. Coexisting ASD contributed to the poor outcome. Core anorectic symptoms had "normalised" three decades after AN onset. Some individuals with anorexia nervosa (AN) also suffer from autism. In this study we have investigated outcome of AN 30 years after the onset of AN and whether the presence of autism affects the outcome. Since the 1980s we have followed 51 individuals with teenage-onset AN and 51 healthy controls. They have been examined on five occasions, and an instrument that measures symptoms of AN (weight, dieting, body image), psychiatric symptoms, ability to work, and relationships with partner, family, and friends has been used to assess outcome. Autism was assessed in the first four studies. Symptoms of AN had normalised at 30-year follow-up, but only among those without autism. Psychiatric symptoms, ability to work, and relationships were issues that persisted after 30 years in the AN group, and those who had both autism and a history of AN had even more pronounced problems in these areas. The AN group had a more negative attitude to sexual matters than the control group, the outcome was worse the more often an autism diagnosis had been assigned.ConclusionsMental health, psychosexual, and socioeconomic status are affected up to 30 years after AN onset, particularly among those with autism.

Project description:Background: Anorexia nervosa (AN) is a life-threatening illness with poor treatment outcomes. Although transcranial direct current stimulation (tDCS) is a promising non-invasive brain stimulation method, its effect in patients with AN remains unclear. Objective: This study investigated changes in maladaptive eating behavior, body mass index (BMI), and depression after 10 sessions of anodal tDCS over the left dorsolateral prefrontal cortex (DLPFC). Methods: In this double-blind, randomized controlled trial, 43 inpatients with AN were divided to receive either active (n = 22) or sham (n = 21) tDCS over the left DLPFC (anode F3/cathode Fp2, 2 mA for 30 min). All patients filled the Eating Disorder Examination Questionnaire (EDE-Q) and Zung Self-Rating Depression Scale (ZUNG), and their BMI was measured. These values were obtained repeatedly in four stages: (1) before tDCS treatment, (2) after tDCS treatment, (3) in the follow-up after 2 weeks, and (4) in the follow-up after 4 weeks. Results: Primary outcomes (EDE-Q) based on the ANOVA results do not show any between-group differences either after the active part of the study or in the follow-up. Secondary analysis reveals a reduction in some items of EDE-Q. Compared with sham tDCS, active tDCS significantly improved self-evaluation based on body shape (p < 0.05) and significantly decreased the need of excessive control over calorie intake (p < 0.05) in the 4-week follow-up. However, the results do not survive multiple comparison correction. In both sham and active groups, the BMI values improved, albeit not significantly. Conclusion: We did not observe a significant effect of tDCS over the left DLPFC on complex psychopathology and weight recovery in patients with AN. tDCS reduced the need to follow specific dietary rules and improved body image evaluation in patients with AN. Tests with a larger sample and different positions of electrodes are needed. Clinical Trial Registration: www.ClinicalTrials.gov, identifier: NCT03273205.

Dataset Information

The Effects of Acute Dopamine Precursor Depletion on the Reinforcing Value of Exercise in Anorexia Nervosa.

Publications

The Effects of Acute Dopamine Precursor Depletion on the Reinforcing Value of Exercise in Anorexia Nervosa.

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