TY - GEN
T1 - Cognitive performance and weight gain in patients with severe anorexia nervosa
AU - Hemmingsen, Simone Daugaard
PY - 2023/6/19
Y1 - 2023/6/19
N2 - Introduction: Anorexia nervosa is characterized by fear of weight gain, a distorted body
perception, and restricted food intake leading to low body weight. There is no consensus
on the definition of severe anorexia nervosa. The Diagnostic and Statistical Manual of
Mental Disorders 5th edition presents categories of severe anorexia nervosa (body mass
index 15-15.99 kg/m2
) and extreme anorexia nervosa (body mass index <15 kg/m2
).
Severe underweight may affect cognitive functioning and mental health in patients with
anorexia nervosa. However, studies investigating whether cognitive functioning is retained
or can be regained in patients with severe and extreme anorexia nervosa are needed. A
deeper understanding of the cognitive mechanisms involved in severe and extreme
anorexia nervosa could provide the basis for highly warranted adaptation and development
of treatments for these patients. Objectives: The PhD thesis includes four studies (five papers) and addresses the
following objectives:
Study 1: Investigate whether cognitive performance improves following weight gain in
patients with anorexia nervosa
Study 2: Determine whether patients with severe and extreme anorexia nervosa have
cognitive flexibility difficulties
Study 3: Investigate changes in cortisol, depression, and anxiety levels during
hospitalization in patients with severe and extreme anorexia nervosa
Study 4: Examine cognitive performance in patients with severe and extreme anorexia
nervosa, and whether weight gain during hospitalization is associated with improved
cognitive performance.Methods: Study 1 (Paper 1) was a systematic review of cognitive performance and weight
gain in patients with anorexia nervosa. Study 2 (Paper 2) used a cross-sectional design to
investigate cognitive flexibility in patients with severe and extreme anorexia nervosa
compared to healthy control participants. Study 3 (Paper 3) was a longitudinal study that
investigated cortisol concentrations and depression and anxiety symptoms in patients with
severe and extreme anorexia nervosa. Study 4 (Paper 4) examined memory, cognitive
flexibility, attention, and processing speed in patients with severe and extreme anorexia
nervosa in a longitudinal design. A case report was conducted after the inclusion of an
extreme case in Study 4 (Paper 5).The three clinical studies included patients hospitalized in the specialized Nutrition Unit at
the Department of Endocrinology at Odense University Hospital in Denmark. They were
diagnosed according to the Diagnostic and Statistical Manual of Mental Disorders 5th
edition. Study 1: The systematic review was performed in accordance with the Preferred Reporting
Items for Systematic Reviews and Meta-analyses (PRISMA) statement. It was registered
at PROSPERO (ID CRD42019081993) prior to the literature searches in the databases
PubMed, PsychInfo, EMBASE, and Cochrane Library. Study 2: Cognitive flexibility was assessed in patients with severe and extreme anorexia
nervosa and healthy control participants using the Wisconsin Card Sorting Test.Study 3: Plasma and 24-hour urine cortisol concentrations and self-reported depression,
anxiety, and stress symptoms were measured in patients at hospital admission and at
discharge. Study 4: Cognitive performance was investigated with the Wechsler Memory Scale III, the
d2 Test of Attention, The Wechsler Adult Intelligence Scale IV (Processing Speed Index),
and the Delis Kaplan Executive Function System (Verbal Fluency, Design Fluency, and
Trail Making) in patients at hospital admission, at discharge, and at follow-up.Results: The systematic review (Study 1, Paper 1) included 24 research papers that
investigated cognitive performance in patients with anorexia nervosa before and after
weight gain. The literature was limited, and the studies used a variety of tests. For the
studies that investigated adults, few used similar cognitive tests and they found mixed
results. In children and adolescents, processing speed seemed to improve after weight
gain contrary to cognitive flexibility. In Study 2 (Paper 2), the 34 patients included had lower cognitive flexibility than the 34
healthy control participants after controlling for age and years of education. We found no
significant associations between cognitive flexibility and body mass index, illness duration,
depression, or eating disorder symptoms among patients with severe and extreme
anorexia nervosa.Out of 36 patients investigated at admission, 27 patients completed measurements at
discharge in Study 3 (Paper 3). We found no statistically significant changes in cortisol,
depression, and anxiety levels during hospitalization in the patients with severe and
extreme anorexia nervosa. Nor did we find any associations between cortisol and
psychopathology. In Study 4 (Paper 4), we found that the 33 patients included had normal cognitive
performance. Of these, 22 patients completed discharge assessments and 18 completed
follow-up assessments a few months after discharge. Between admission and discharge,
the patients gained a mean of 11.3% body weight and significantly improved memory,
processing speed, and concentration performance. However, we found no statistically significant associations between the cognitive improvement and percentage weight gain.
Between discharge and follow-up, we found no improvement in performance.
The case report (Paper 5) described a 35-year-old woman with a body mass index of 7.7
who performed normal on cognitive measurements, except cognitive flexibility assessed
with the Wisconsin Card Sorting Test.Conclusion: Based on the studies in this PhD thesis, neuropsychological assessment of
severely malnourished patients with anorexia nervosa is possible. Patients with severe
and extreme anorexia nervosa seemed to have normal cognitive performance, despite
being severely underweight and depressed, but seemed to display cognitive inflexibility
compared to healthy control individuals. A theory of cognitive adaptation to severe
malnutrition in patients with anorexia nervosa was introduced. It was recommended to
evaluate individually whether a patient with severe or extreme anorexia nervosa has
specific cognitive difficulties that may be assessed and addressed in treatment. In addition,
it was suggested that future studies of cognitive performance should distinguish between
children, adolescents, and adults. Future research on larger samples could compare
patients with anorexia nervosa with very low body mass indexes to patients with higher
body mass indexes, in order to investigate whether weight status in adults with anorexia
nervosa is associated with cognitive performance.
AB - Introduction: Anorexia nervosa is characterized by fear of weight gain, a distorted body
perception, and restricted food intake leading to low body weight. There is no consensus
on the definition of severe anorexia nervosa. The Diagnostic and Statistical Manual of
Mental Disorders 5th edition presents categories of severe anorexia nervosa (body mass
index 15-15.99 kg/m2
) and extreme anorexia nervosa (body mass index <15 kg/m2
).
Severe underweight may affect cognitive functioning and mental health in patients with
anorexia nervosa. However, studies investigating whether cognitive functioning is retained
or can be regained in patients with severe and extreme anorexia nervosa are needed. A
deeper understanding of the cognitive mechanisms involved in severe and extreme
anorexia nervosa could provide the basis for highly warranted adaptation and development
of treatments for these patients. Objectives: The PhD thesis includes four studies (five papers) and addresses the
following objectives:
Study 1: Investigate whether cognitive performance improves following weight gain in
patients with anorexia nervosa
Study 2: Determine whether patients with severe and extreme anorexia nervosa have
cognitive flexibility difficulties
Study 3: Investigate changes in cortisol, depression, and anxiety levels during
hospitalization in patients with severe and extreme anorexia nervosa
Study 4: Examine cognitive performance in patients with severe and extreme anorexia
nervosa, and whether weight gain during hospitalization is associated with improved
cognitive performance.Methods: Study 1 (Paper 1) was a systematic review of cognitive performance and weight
gain in patients with anorexia nervosa. Study 2 (Paper 2) used a cross-sectional design to
investigate cognitive flexibility in patients with severe and extreme anorexia nervosa
compared to healthy control participants. Study 3 (Paper 3) was a longitudinal study that
investigated cortisol concentrations and depression and anxiety symptoms in patients with
severe and extreme anorexia nervosa. Study 4 (Paper 4) examined memory, cognitive
flexibility, attention, and processing speed in patients with severe and extreme anorexia
nervosa in a longitudinal design. A case report was conducted after the inclusion of an
extreme case in Study 4 (Paper 5).The three clinical studies included patients hospitalized in the specialized Nutrition Unit at
the Department of Endocrinology at Odense University Hospital in Denmark. They were
diagnosed according to the Diagnostic and Statistical Manual of Mental Disorders 5th
edition. Study 1: The systematic review was performed in accordance with the Preferred Reporting
Items for Systematic Reviews and Meta-analyses (PRISMA) statement. It was registered
at PROSPERO (ID CRD42019081993) prior to the literature searches in the databases
PubMed, PsychInfo, EMBASE, and Cochrane Library. Study 2: Cognitive flexibility was assessed in patients with severe and extreme anorexia
nervosa and healthy control participants using the Wisconsin Card Sorting Test.Study 3: Plasma and 24-hour urine cortisol concentrations and self-reported depression,
anxiety, and stress symptoms were measured in patients at hospital admission and at
discharge. Study 4: Cognitive performance was investigated with the Wechsler Memory Scale III, the
d2 Test of Attention, The Wechsler Adult Intelligence Scale IV (Processing Speed Index),
and the Delis Kaplan Executive Function System (Verbal Fluency, Design Fluency, and
Trail Making) in patients at hospital admission, at discharge, and at follow-up.Results: The systematic review (Study 1, Paper 1) included 24 research papers that
investigated cognitive performance in patients with anorexia nervosa before and after
weight gain. The literature was limited, and the studies used a variety of tests. For the
studies that investigated adults, few used similar cognitive tests and they found mixed
results. In children and adolescents, processing speed seemed to improve after weight
gain contrary to cognitive flexibility. In Study 2 (Paper 2), the 34 patients included had lower cognitive flexibility than the 34
healthy control participants after controlling for age and years of education. We found no
significant associations between cognitive flexibility and body mass index, illness duration,
depression, or eating disorder symptoms among patients with severe and extreme
anorexia nervosa.Out of 36 patients investigated at admission, 27 patients completed measurements at
discharge in Study 3 (Paper 3). We found no statistically significant changes in cortisol,
depression, and anxiety levels during hospitalization in the patients with severe and
extreme anorexia nervosa. Nor did we find any associations between cortisol and
psychopathology. In Study 4 (Paper 4), we found that the 33 patients included had normal cognitive
performance. Of these, 22 patients completed discharge assessments and 18 completed
follow-up assessments a few months after discharge. Between admission and discharge,
the patients gained a mean of 11.3% body weight and significantly improved memory,
processing speed, and concentration performance. However, we found no statistically significant associations between the cognitive improvement and percentage weight gain.
Between discharge and follow-up, we found no improvement in performance.
The case report (Paper 5) described a 35-year-old woman with a body mass index of 7.7
who performed normal on cognitive measurements, except cognitive flexibility assessed
with the Wisconsin Card Sorting Test.Conclusion: Based on the studies in this PhD thesis, neuropsychological assessment of
severely malnourished patients with anorexia nervosa is possible. Patients with severe
and extreme anorexia nervosa seemed to have normal cognitive performance, despite
being severely underweight and depressed, but seemed to display cognitive inflexibility
compared to healthy control individuals. A theory of cognitive adaptation to severe
malnutrition in patients with anorexia nervosa was introduced. It was recommended to
evaluate individually whether a patient with severe or extreme anorexia nervosa has
specific cognitive difficulties that may be assessed and addressed in treatment. In addition,
it was suggested that future studies of cognitive performance should distinguish between
children, adolescents, and adults. Future research on larger samples could compare
patients with anorexia nervosa with very low body mass indexes to patients with higher
body mass indexes, in order to investigate whether weight status in adults with anorexia
nervosa is associated with cognitive performance.
U2 - 10.21996/v457-3x16
DO - 10.21996/v457-3x16
M3 - Ph.D. thesis
PB - Syddansk Universitet. Det Sundhedsvidenskabelige Fakultet
ER -