Chapter 26: Autism spectrum disorders

Question 1

What is Autism spectrum disorder (ASD)?

Answer 1

• Autism spectrum disorder (ASD) = a developmental disorder involving behavioral deficits in 2 distinct domains:
  1. Persistent deficits in social communication and social interaction, and

2. Restricted, repetitive patterns of behavior, interests and activities.

Question 2

Which levels of severity does the DSM-5 distinguish and what are these levels based on?

Answer 2

• DSM-5 distinguishes the levels of severity of ASD based on the degree of support at each level.
• The levels are:
• Level 1: requires support.
• Level 2: requires substantial support.
• Level 3: requires very substantial support.

Question 3

Why is making an ASD diagnosis more complex in adulthood than in childhood?

Answer 3

• ASD is adulthood almost always concerns a milder form within the autism spectrum, in which people have learned social behavior over the years as compensation and camouflage for the autistic symptoms.
• When a patient presents to the mental healthcare at adult age, there are often comorbid disorders or psychosocial problems, which can obscure the autistic symptomatology.
• A developmental history is no longer possible at an adult age.
• It can be difficult to distinguish between ASD, anxiety disorders and schizophrenia because there is a great overlap.
• There is also a phenomenological overlap with various personality disorders.

Question 4

What are common features that mark problems in social interaction, communication and behavior in ASD, despite the heterogeneity in the clinical picture?

Answer 4

• Avoiding eye contact (some people have to consciously learn to make eye contact, which can become ‘staring’).
• Monotone and little/no voice attuned to the situation.
• Little use of supportive gestures, rigid motor skills.
• Formal and pendant language.
• Difficulty with structure.
• Difficulty with communicating or little initiative in this.
• Highly value fixed routines/predictability.
• Sensory under- or over-sensitivity.
• Abnormal information processing (easily overstimulated).

Question 5

What are factors that play a role in that the prevalence of ASD has risen?

Answer 5

• ASD is recognized early than it used to.
• ASD is better diagnosed.
• The world is getting more demanding (e.g., of social skills).

Question 6

What do twin studies tell us about ASD?

Answer 6

• Twin studies have shown that ASD is approximately 90% genetically determined, making it one of the most heritable disorders within psychiatry.

Question 7

What have research into ASD subgroups shown about chromosomes associated with ASD?

Answer 7

• Chromosomes 2 and 7 are associated with language developmental problems.
• Chromosomes 1, 15 and 17 are thought to be associated with language rigidity and obsessive-compulsive behavior.
• A link between the X chromosome and ASD is also thought to exist, since ASD occurs 4x more often in men and women (women have another X chromosome to compensate the defect on the one X chromosome and men don’t).

Question 8

What has research shown about cerebrum/brain volume abnormalities in people with ASD?

Answer 8

• +/- 20% of children with ASD have macrocephaly.
• Macrocephaly = a head circumference 2 standard deviations larger than the population average.
• This is related to the size of the brain mass (particularly frontal and temporal lobes).
• Growth mainly occurs during first 2 years of life, but the growth process of the brain volume is slower in the 5th year of life.
• As a result of white matter disorders in adolescents and adults with ASD, there appears to be reduced integration and connectivity, particularly in frontostriatal and parieto-occipital networks.
• The increase in brain volume is in turn counterbalanced by a decrease in the volume of the corpus callosum.

Question 9

What has research shown about the limbic system and cerebellum in people with ASD?

Answer 9

• Research about the limbic system in people with ASD has found:
• A higher cell density with smaller cells was found in the hippocampus, the amygdala and the entorinal cortex in all age groups.
• The amygdala is less activated in people with ASD for recognizing faces and for tasks that call on the theory of mind (because of reduces emotional arousal to stimuli).
• On the other hand, the amygdala seems over-activated when people with ASD look someone in the eye (> has to do with social anxiety).
• No abnormalities were found in the activation of the fusiform face area (FFA).
• Research about the cerebellum in people with ASD has found:
• Fewer purkinje cells are found in the posterior inferior parts of the hemispheres, as well as deviations in growth development.
• The cerebellar abnormalities in ASD are usually related to motor clumsiness and attention problems.
• There are indications that the mirror neuron system does not function properly in people with ASD (particularly in social or emotional tasks).

Question 10

What has research about neurochemistry and endocrinology found in people with ASD?

Answer 10

• Neurochemical studies of ASD have not yet provided an unambiguous picture and there are no known effective pharamceutical interventions for the core symptoms of ASD.
• Medication for ASD is therefore focused on the psychiatric comorbidity.
• Increased serotonin levels in early development can lead to loss of serotonin receptors, resulting in disrupted neuronal development.
• Peripheral serotonin levels are elevated in +/- 1/3 of people with ASD.
• Testosterone also has received a great deal of attention.
• Oxytocin also has a possible therapeutic effect on the core social symptoms of ASD.

Question 11

What is the extreme male brain theory of autism?

Answer 11

• The extreme male brain theory of autism = posits the idea that ASD is an extreme form of male thinking.

Question 12

What is the theory of mind (ToM)?

Answer 12

• The theory of mind = the ability to put one’s thoughts, feelings and intentions into someone else’s place.
• This makes ToM an important condition for being able to move (understand and predict) in a social environment.

Question 13

What has research of the theory of mind shown about people with ASD?

Answer 13

• That people with ASD do not have a fundamental defect in ToM, but rather a delay in the development of ToM skills.
• Individuals with ASD continue to have problems with social interactions, although they’re often able to perform correctly on ToM tasks.
• It is also possible that people with ASD barely use ToM.
• The most common hypothesis is that ASD involves a deficit in spontaneous mentalizing.

Question 14

What does spontaneous mentalizing mean?

Answer 14

• Sponteneous mentalizing = spontaneously encoding socially relevant information and automatically processing the mental states of another.

Question 15

What does the central coherence hypothesis about ASD mean and involve?

Answer 15

• The central coherence hypothesis = people with ASD cannot automatically process information globally and in context in order to arrive at a meaningful, coherent interpretation of the environment, but they can process information fragmentally and at a local level.
• According to Frith, people with ASD have a weak central coherence.
• A clouding factor in this theory is that central coherence is always operationalized in a different way.
• Weak central coherence is composed of 2 factors:
  1. Good analytical perception.
  2. Weak meaning perception.
• Other research found that central coherence is not so much a problem in recognizing global features or seeing meaning, but rather about preference (bias) for processing information at the local level.
• Central coherence is a feature that varies in the normal population and is therefore seen as a stylistic feature rather than a defect.

Question 16

What has research about the executive function in people with ASD suggested?

Answer 16

• That disorders of executive functions may underlie autistic symptoms (but still much uncertainty).
• A lack of cognitive flexibility is most frequently mentioned as typical of ASD and is therefore often associated with the rigidity that emerges in the stereotypical behaviors and interests of people with ASD.
• However, research has shown that there’s no direct relationship between cognitive flexibility and behavioral rigidity. There are several explanations for the often contradictory findings:
• There are general problems inherent in measuring executive functioning with structured tasks within a standardized test setting, lack of clarity about what executive functioning is, and the fact that different tasks are used to measure different aspects of concepts.
• The social interaction between the person with ASD and the test assistant plays a role (> better performance with no assistant present).

Question 17

What is the empathizing-systemizing theory and what does it involve?

Answer 17

• The empathizing-systemizing theory = states that the capacity for empathy consists of the ability to ascertain one’s mental state and also the ability to respond appropriately to the other person’s feelings and thought.
• According to the empathizing-systemizing theory, both social and non-social behavioral characteristics can be explained from a discrepancy between empathy and the ability to analyse or construct systems.
• This discrepancy was labeled as an extreme form of masculine thinking.

Question 18

How is the concept of systemizing defined in the empathizing-systemizing theory?

Answer 18

• Systemizing = the will to analyse and construct systems.

Question 19

What factors make the conceptual unity of ASD less likely?

Answer 19

• It is plausible that the different behavioral systems of ASD have no common basis at the genetic, neurological, or cognitive level.
• Also, each of the behavioral symptoms has its own neuronal circuit.

Question 20

What factors make the conceptual unity of ASD less likely?

Answer 20

• It is plausible that the different behavioral systems of ASD have no common basis at the genetic, neurological, or cognitive level.
• Also, each of the behavioral symptoms has its own neuronal circuit.

Question 20

What are endophenotypes?

Answer 20

• Endophenotypes are biological or neuropsychological markers that are:
• In the population related to disease.
• Hereditary themselves.
• Detectable when the disease is not manifest.
• Present within families at the same time.
• More common among relatives of patients than in the general population.