Autism: Definition, Diagnostics and Causes

Autism is a puzzle. Indeed, the international symbol used to represent Autism is a puzzle piece(s). Most people believe the puzzle piece is used as a symbol of how autistic people do not fit into society, yet others believe that the puzzle piece stands for the uniqueness of each individual affected by Autism, or that the puzzle piece represents the piece of the puzzle that is missing in finding a cure for Autism. Although there are many misconceptions about what the puzzle piece means, the puzzle piece was chosen to represent Autism to symbolize the mysteriousness of this disorder (Pinning Down Autism, 2007). Much remains ambiguous about this disorder: the causes, the treatment, the prognosis, the prevention, and the cure.

Diagnostics

Autism is also puzzling because the disorder presents differently in each individual; no two people with Autism are exactly alike, they neither have the same strengths, nor the same weaknesses, which makes it especially difficult to narrow down the causes of Autism. Autism is classified by the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM IV) as belonging to the category of Pervasive Developmental Disorders (PDD). Pervasive Developmental Disorders are a group of disorders that are categorized based on delays or difficulties in communication skills and impaired social interactions (National Institute of Neurological Disorders and Stroke, 2011). Other disorders belonging in the category of Pervasive Developmental Disorders, in addition to Autism, include Rett's Disorder, Childhood Disintegrative Disorder, Asperger's Disorder, and Pervasive Developmental Disorder Not Otherwise Specified which includes Atypical Autism.

Interestingly, proposed revisions to the 2012 edition of the DSM V includes: complete removal of Rett's Disorder and combining Childhood Disintegrative Disorder, Asperger's Disorder, and Pervasive Developmental Disorder Not Otherwise Specified into the broad category of Autism Spectrum Disorder (American Psychiatric Association, 2010). Additionally, the "new" symptom of Sensory Integration Dysfunction (over or under reactivion to sensory stimuli) is proposed to be added to the diagnostic criterion for Autism Spectrum Disorders, which is currently not recognized as a symptom of any of the current separate categories of the Pervasive Developmental Disorders in the DSM IV (2010). Every parent with a child on the Autism Spectrum would have to agree that it is about time this symptom were added to the criterion for diagnosis; Sensory Integration Dysfunction is part-and-parcel of the everyday life experience of a person with Autism, affecting the individual just as intensely as all the other symptoms of Autism.

Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, (DSM IV)

In the DSM IV, an individual must present with at least six of the following criterion (American Psychiatric Association, 1995):

1) Impairment of social interaction, individual must present with at least two of the following (1995):
a) Inability to appropriately regulate social interaction behaviors such as eye contact, body postures, and gestures (1995)
b) Inability to foster age-appropriate peer relationships (1995)
c) Notable lack of spontaneous sharing of enjoyment with others (i.e. interests, achievements, etc.) (1995)
d) Deficiency in social and/or emotional interaction (1995)
2) Communication deficits; individual must present with at least one of the following (1995):
a) Deficit, delay, or lack of spoken language development (1995)
b) Individuals with appropriate speech demonstrate a lack of ability to initiate or maintain conversations with others (1995)
c) Demonstration of stereotypical, repetitive, or eccentric use of language (1995)
d) Notable lack of spontaneous imaginative, imitative, or make-believe play that is age appropriate (1995)
3) Repetitive, stereotypical behaviors, actions, or interests; individual must present with at least one of the following (1995):
a) Preoccupation with stereotypical interests that is abnormal in intensity or focus (1995)
b) Adherence to routines, rituals, and schedules with inability to be flexible when change occurs (1995)
c) Stereotypical and repetitive movements (i.e. hand/finger/arm flapping, twisting, rocking, etc.) (1995)
d) Tenacious obsession with objects (1995)

Additionally, delays in normal functioning with social interactions, social language communications, or imaginative play must present prior to the age of three; and the individual's delays are not better accounted for by another of the Pervasive Developmental Disorders (1995).

Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM V)

In the DSM IV, an individual must meet all four criteria (A, B, C, and D):

A) Deficits in social communication and interactions, individual must present with all three of the following criteria (American Psychiatric Association, 2011):
1) Deficiency in social and/or emotional interaction and communication, lack of ability to initiate or maintain conversations with others, notable lack of spontaneous sharing of enjoyment with others (i.e. interests, achievements, etc.) (2011)
2) Inability to appropriately regulate social interaction behaviors such as eye contact, body postures, and gestures, deficit, delay, or lack of spoken language development, lack of ability to initiate or maintain verbal and non-verbal conversations with others (2011)
3) Inability to foster age-appropriate peer relationships, little interest in other people, notable lack of spontaneous imaginative, imitative, or make-believe play that is age appropriate (2011)
B) Repetitive, stereotypical behaviors, actions, or interests; individual must present with at least two of the following (2011)
1) Demonstration of stereotypical, repetitive, or eccentric use of language (2011)
2) Adherence to routines, rituals, and schedules with inability to be flexible when change occurs (2011)
3) Preoccupation with stereotypical interests that is abnormal in intensity or focus (2011)
4) Sensory Integration Dysfunction (2011)
C) Symptoms present during early childhood (2011)
D) Symptoms inhibit or interfere with ability to function (2011)

It is clearly evident that the difference between the new and the old Diagnostic Statistics Manual are quite significant. In addition to classifying all Pervasive Developmental Disorders together under the same heading of Autism Spectrum Disorder, many of the diagnostic criteria are combined and expanded. The proposed changes to the DSM V do appear to make diagnosis easier and simpler. If the proposed changes meet final approval, the American Psychiatric Association will have accomplished this goal in the DSM V through the classification all the Pervasive Developmental Disorders under the single heading of Autism Spectrum Disorders, combining the diagnostic criteria (also eliminating unnecessary repetitions), and clarifying the diagnostic criteria.

Research into the Causes

The cause(s) of Autism remain a mystery at this time. It is known that there are genetic factors involved in Autism, as according to Levy (2009), "the relative risk of a second child having this diagnosis is 20-50 times higher than the population base rate" (p. 1632). Levy also notes that parents, as well as siblings, even when not diagnosed with Autism, will demonstrate various symptoms along the spectrum of Autism, including language delays, language difficulties as relates to social aspects, delays in social development, lack of close friendships, perfectionism, and/or a rigid personality (2009). It is important to note that Autism is a multifaceted disorder; many different factors interact to produce this unique disorder. Levy (2009) notes that the differences between the manifestation of Autism in monozygotic and dizygotic twins allude to the fact that Autism is caused by gene-on-gene as well as gene-on-environment interactions, hence, the difficulty in finding a cure or prevention for this disorder.

Plausible evidence suggests that autism is caused by abnormalities in the brain's structure and biochemical makeup (Carlson, 2011). It is believed that approximately 20 percent of autism cases are caused by biological issues including: herpes derived encephalitis, prenatal thalidomide, contraction of rubella during pregnancy, and tuberous sclerosis (2011). Indeed, Carlson (2011) noted that abnormalities in brain development of children with Autism from infancy to adolescence, at which time the Autistic brain remains about one or two percent larger than normal. Abnormalities are also noted in the structure of the cerebral cortex, including an increased number of short-range axons (but not long-range axons) in white matter, increased gyri in the frontal lobes, and the number and spacing of neurons (2011).

One theory hypothesizes that high levels of serotonin (hyperserotonemia) is the cause of the behavior and cellular deviations seen in Autism. The hypothesis states that during prenatal development, prior to the formation of the blood-brain barrier, large blood levels of serotonin enter the fetal brain causing damage to serotonin terminals; this forfeiture of serotonin terminals is permanent causing the eventual symptoms of Autism (Whittaker-Azmitia, 2005). Research using the serotonin agonist, 5-methoxytryptamine (5-MT) was conducted on rats, whose serotonin terminal development is closely related to that of humans. These studies found that the rats administered 5-MT from the 12th to 20th day of gestation demonstrated a reduction in metabolic activity in the cortex, changes were observed in the cortex columnar development, an increase was found in the calcitonin gene related peptide in the amygdala central nucleus (fear response region of the brain), a reduction in oxytocin was discovered in the hypothalamus paraventricular nucleus (area of the brain involved in bonding and social memory), changes were noted in serotonin receptors, and the rats displayed "autistic-like" behavior (2005). Of particular interest are the roles that oxytocin and serotonin play in social recognition, social memory, pro-social behaviors, and an increase in fear response (2005). It is noteworthy that children treated with oxytocin infusions experience a reduction in some autistic behaviors (2005). This and future research into the roles of serotonin and oxytocin, as well as methods of treating, reversing, or preventing a loss of serotonin and oxytocin, may provide a missing piece of the Autism puzzle.

Attempts to narrow down a single theory to explain the basic and comorbid deficits seen in Autism has been largely futile; this lack of success is believed to be due to the pre- and postnatal neural development and the lack of uniformity in the presentation of symptoms across the Autism Spectrum Disorder (Levy, 2009). Neurobiological research has discovered macrocephaly in approximately 20 percent of Autistic children; overgrowths of cortical white matter; abnormal growth patterns in the frontal and temporal lobes as well as the limbic structures (including the amygdala); cytoarchitectural abnormalities, including a reduction in number and size of purklnje cells; cortical minicolumn abnormalities; impeded neuronal activity in the inferior frontal gyrus; disruptions in white matter in the areas of the brain associated with social functioning; a reduction in the functional connectivity in areas of the brain related to working memory, social cognition and perception, language, and problem solving; and hypoactivation in the fusiform face area (area of the brain associated with the perception of people versus objects (2009).

Conclusion

Autism is indeed quite puzzling. The causes of Autism, to this day, remain a mystery. The symptoms and manifestations of this disorder present differently, thus affecting each individual differently, and unfortunately, make this puzzle even more difficult to solve. Thanks to the American Psychiatric Association, the symptoms of Autism are easier for physicians to recognize, thus allowing children to get treatment earlier and improving the prognosis. Research, too, is expanding into new territories and offering promising new insights into the disorder; yet this research also offers new hope that one day humankind will understand the mysteries and discover the causes, treatments, preventions and cures for Autism.

References

American Psychiatric Association. (1995). Diagnostic and statistical manual of mental disorders, 4th ed. Washington, DC; American Psychiatric Association.

American Psychiatric Association. (2010). Disorders usually first diagnosed in infancy, childhood, or adolescence. American Psychiatric Association DSM-5 Development. Retrieved from http://www.dsm5.org/ProposedRevisions/Pages/InfancyChildhoodAdolescence.....

American Psychiatric Association. (2011). A 09: Autism Spectrum Disorder. American Psychiatric Association DSM=5 Development. Retrieved from http://www.dsm5.org/ProposedRevisions/Pages/proposedrevision.aspx?rid=94.

Carlson, N. R. (2011). Foundation of behavioral neuroscience, 8th ed. Boston, MA; Pearson Education, Inc., publishing as Allyn & Bacon.

Levy, S. E. (2009). Autism. The Lancet; 374(9701). DOI: 10.1016/S0140-6736(09)61376-3

National Institute of Neurological Disorders and Stroke. (2011). NINDS pervasive developmental disorders information page. National Institute of Neurological Disorders and Stroke. Retrieved from http://www.ninds.nih.gov/disorders/pdd/pdd.htm.

Pinning Down Autism. (2007). The significance of the puzzle piece image. Pinning Down Autism Foundation. Retrieved from http://www.pinningdownautism.com/autism.html.