Are ASD's really becoming more common?

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Good day folks,

If what I'm going to talk about here isn't apparent by the title of the thread, then I am very sorry, I can't help you figure it out.

Let's cut the chit-chat. If you go back to the 1950s, ASD's were considered to be very rare, but, since the 1980s, the numbers have grown exponentially; between 1996 and 2007, numbers grew from 0.08% to 0.52%, and as of 2010, numbers run at 1.47%.

Do I believe that ASD's are becoming more common? Will those with ASD grow to outnumber NT's? Well, I did a quick regression analysis using MS excel (my equation, while not perfect, comes to y=0.6757e^0.2076x), and at this rate (if the frequency of autism is really growing exponentially, and doesn't stop), the majority (>50%) of the population will have a diagnosed ASD by the year... 2028 (10 years from the time of this post!) and the allele becomes fixed (i.e. the entire population has autism) by the year... 2031.

Does this make logical sense? I am not entirely sure, surely the numbers must level off someday. Maybe my exponential growth model is flawed, but even if the growth follows a logistic model, the frequency of ASD would still follow the exponential model until the half-way point. (If the math/stats-language has you lost, skip it -- I won't test you on it later)

My personal belief is that the frequency of ASD's hasn't changed that much over the years; maybe it's increased slightly, but it can't be that dramatic. Rather, it's becoming more common because of a change in diagnostic criteria and because of more awareness.

The old DSM-III criteria for ASD were:

1980: DSM-III wrote:
A. Onset before 30 months of age

B. Pervasive lack of responsiveness to other people

C. Gross deficits in language development

D. If speech is present, peculiar speech patterns such as immediate and delayed echolalia, metaphorical language, pronominal reversal

E. Bizarre responses to various aspects of the environment, e.g., resistance to change, peculiar interest in or attachments to animate or inanimate objects

ow let's move ahead to the DSM-IV, with both the criteria for autism and Aspergers.

1994: DSM-IV wrote (autism)
The central features of Autistic Disorder are the presence of markedly abnormal or impaired development in social interaction and communication, and a markedly restricted repertoire of activity and interest. The manifestations of this disorder vary greatly depending on the developmental level and chronological age of the individual. Autistic Disorder is sometimes referred to as Early Infantile Autism, Childhood Autism, or Kanner’s Autism (page 66).

A. A total of six (or more) items from (1), (2), and (3), with at least two from (1), and one each from (2) and (3):

Qualitative impairment in social interaction, as manifested by at least two of the following:
Marked impairment in the use of multiple nonverbal behaviors such as eye to-eye gaze, facial expression, body postures, and gestures to regulate social interaction .
Failure to develop peer relationships appropriate to developmental level
A lack of spontaneous seeking to share enjoyment, interests, or achievements with other people (e.g., by a lack of showing, bringing, or pointing out objects of interest)
Lack of social or emotional reciprocity
Qualitative impairments in communication as manifested by at least one of the following:
Delay in, or total lack of, the development of spoken language (not accompanied by an attempt to compensate through alternative modes of communication such as gestures or mime)
In individuals with adequate speech, marked impairment in the ability to initiate or sustain a conversation with others
Stereotyped and repetitive use of language or idiosyncratic language
Lack of varied, spontaneous make-believe play or social imitative play appropriate to developmental level
Restricted repetitive and stereotyped patterns of behavior, interests, and activities, as manifested by at least one of the following:
Encompassing preoccupation with one or more stereotyped patterns of interest that is abnormal either in intensity or focus
Apparently inflexible adherence to specific, nonfunctional routines or rituals
Stereotyped and repetitive motor mannerisms (e.g., hand or finger flapping or twisting, or complex whole-body movements)
Persistent preoccupation with parts of object

B. Delays or abnormal functioning in at least one of the following areas, with onset prior to age 3 years:

Social interaction
Language as used in social communication
Symbolic or imaginative play

C. The disturbance is not better accounted for by Rett’s Disorder or Childhood Disintegrative Disorder.

--------------------

1994: DSM-IV wrote (Aspergers)
The essential features of Asperger’s Disorder are severe and sustained impairment in social interaction and the development of restricted, repetitive patterns of behavior, interest, and activity. The disturbance must clinically show significant impairment in social, occupational, and other important areas of functioning. In contrast to Autistic Disorder, there are no clinically significant delays in language. In addition there are no clinically significant delays in cognitive development or in the development of age-appropriate self-help skills, adaptive behavior, and curiosity about the environment in childhood.

A. Qualitative impairment in social interaction, as manifested by at least two of the following:

Marked impairment in the use of multiple nonverbal behaviors such as eye-to-eye gaze, facial expression, body postures, and gestures to regulate social interaction
Failure to develop peer relationships appropriate to developmental level
A lack of spontaneous seeking to share enjoyment, interests, or achievements with other people (e.g., by a lack of showing, bringing, or pointing out objects of interest to other people)
Lack of social or emotional reciprocity

B. Restricted repetitive and stereotyped patterns of behavior, interests, and activities, as manifested by at least one of the following:

Encompassing preoccupation with one or more stereotyped and restricted patterns of interest that is abnormal either in intensity or focus
Apparently inflexible adherence to specific, non-functional routines or rituals
Stereotyped and repetitive motor mannerisms (e.g., hand or finger flapping or twisting, or complex whole-body movements)
Persistent preoccupation with parts of objects

C. The disturbance causes clinically significant impairment in social, occupational, or other important areas of functioning.

D. There is no clinically significant general delay in language (e.g., single words used by age 2 years, communicative phrases used by age 3 years)

E. There is no clinically significant delay in cognitive development or in the development of age-appropriate self-help skills, adaptive behavior (other than in social interaction), and curiosity about the environment in childhood.

F. Criteria are not met for another specific Pervasive Developmental Disorder or Schizophrenia

Now, moving up to the DSM-V:

A. Persistent deficits in social communication and social interaction across multiple contexts, as manifested by the following, currently or by history (examples are illustrative, not exhaustive, see text):

Deficits in social-emotional reciprocity, ranging, for example, from abnormal social approach and failure of normal back-and-forth conversation; to reduced sharing of interests, emotions, or affect; to failure to initiate or respond to social interactions.
Deficits in nonverbal communicative behaviors used for social interaction, ranging, for example, from poorly integrated verbal and nonverbal communication; to abnormalities in eye contact and body language or deficits in understanding and use of gestures; to a total lack of facial expressions and nonverbal communication.
Deficits in developing, maintaining, and understanding relationships, ranging, for example, from difficulties adjusting behavior to suit various social contexts; to difficulties in sharing imaginative play or in making friends; to absence of interest in peers.

Specify current severity:
Severity is based on social communication impairments and restricted repetitive patterns of behavior (see Table 2).

B. Restricted, repetitive patterns of behavior, interests, or activities, as manifested by at least two of the following, currently or by history (examples are illustrative, not exhaustive; see text):

Stereotyped or repetitive motor movements, use of objects, or speech (e.g., simple motor stereotypies, lining up toys or flipping objects, echolalia, idiosyncratic phrases).
Insistence on sameness, inflexible adherence to routines, or ritualized patterns or verbal nonverbal behavior (e.g., extreme distress at small changes, difficulties with transitions, rigid thinking patterns, greeting rituals, need to take same route or eat food every day).
Highly restricted, fixated interests that are abnormal in intensity or focus (e.g, strong attachment to or preoccupation with unusual objects, excessively circumscribed or perseverative interest).
Hyper- or hyporeactivity to sensory input or unusual interests in sensory aspects of the environment (e.g., apparent indifference to pain/temperature, adverse response to specific sounds or textures, excessive smelling or touching of objects, visual fascination with lights or movement).

C. Symptoms must be present in the early developmental period (but may not become fully manifest until social demands exceed limited capacities, or may be masked by learned strategies in later life).

D. Symptoms cause clinically significant impairment in social, occupational, or other important areas of current functioning.

E. These disturbances are not better explained by intellectual disability (intellectual developmental disorder) or global developmental delay. Intellectual disability and autism spectrum disorder frequently co-occur; to make comorbid diagnoses of autism spectrum disorder and intellectual disability, social communication should be below that expected for general developmental level.

NOTE: Individuals with a well-established DSM-IV diagnosis of autistic disorder, Asperger’s disorder, or pervasive developmental disorder not otherwise specified should be given the diagnosis of autism spectrum disorder. Individuals who have marked deficits in social communication, but whose symptoms do not otherwise meet criteria for autism spectrum disorder, should be evaluated for social (pragmatic) communication disorder.
TABLE 2 SEVERITY LEVELS FOR AUTISM SPECTRUM DISORDER

Level 3: “Requiring very substantial support”
Social Communication:

Severe deficits in verbal and nonverbal social communication skills cause severe impairments in functioning, very limited initiation of social interactions, and minimal response to social overtures from others. For example, a person with few words of intelligible speech who rarely initiates interaction and, when he or she does, makes unusual approaches to meet needs only and responds to only very direct social approaches.
Restricted, Repetitive Behaviours:

Inflexibility of behavior, extreme difficulty coping with change, or other restricted/repetitive behaviors markedly interfere with functioning in all spheres. Great distress/difficulty changing focus or action.

Level 2: “Requiring substantial support”
Social Communication:

Marked deficits in verbal and nonverbal social communication skills; social impairments apparent even with supports in place; limited initiation of social interactions; and reduced or abnormal responses to social overtures from others. For example, a person who speaks simple sentences, whose interaction is limited to narrow special interests, and who has markedly odd nonverbal communication.
Restricted, Repetitive Behaviours:

Inflexibility of behavior, difficulty coping with change, or other restricted/repetitive behaviors appear frequently enough to be obvious to the casual observer and interfere with functioning in a variety of contexts. Distress and/or difficulty changing focus or action.

Level 1: “Requiring support”
Social Communication:

Without supports in place, deficits in social communication cause noticeable impairments. Difficulty initiating social interactions, and clear examples of atypical or unsuccessful response to social overtures of others. May appear to have decreased interest in social interactions. For example, a person who is able to speak in full sentences and engages in communication but whose to-and-fro conversation with others fails, and whose attempts to make friends are odd and typically unsuccessful.
Restricted, Repetitive Behaviours:

Inflexibility of behavior causes significant interference with functioning in one or more contexts. Difficulty switching between activities. Problems of organization and planning hamper independence.

@Moderators: Sorry about posting this in three separate posts (too long for one post). If you can combine these posts and put them into collapsible spoilers, I'd be all the happier.

If you've been observant, you might have noticed that the definition of an ASD became alot broader in 1994 after the DSM-IV was released. Autism rates started to rise in 1996. Seems like a very *cough* interesting coincidence *cough*. Nowadays, it seems like anyone who exhibits trouble socialising will be diagnosed with an ASD, because I strongly suspect that much of the population has had enough of the other "accessory traits" (obsessions, stimming, etc etc) at some time or other (Note the criteria say "currently or by history"). Also, I think the media has a role to play. As soon as a parent sees a socially awkward child, what's the first thing that pops into his mind? That child might be autistic.

That brings me to a final point. Why are ASD's so much more frequently mentioned in the media than, let's say dyslexia? Probably because it's alot harder to hide the signs of an ASD than those of dyslexia, especially if you're not severely affected. If you're a slow reader as a child, you can probably get by using other means of obtaining information (YouTube videos, audiobooks, talking to classmates, etc). Bad spelling? Type everything, use a spell-checker, and none will be the wiser. Get lost easily? Use a GPS. But it is almost impossible to hide social weaknesses in comparison, as these will be revealed everytime you talk to your friends/parents/others in the world.

This is sort of tangent to your topic, but I'm always interested in the history of medicine. I love to see how diagnostic manuals have changed.

It's interesting to connect the advances in medicine and changes in culture.

Even though I was diagnosed in my mid 40s, I meet all of the original requirements for autism. We have always been here, but unaware our issues had a label. Our numbers are increasing because of increased ASD awareness.

My local support group has more grey haired people show up every month, surprised to see other ASD people with grey hair. It is very emotional for some to realize they are not as abnormal as they thought.

I agree with the broader diagnostic criteria.

I would add

Broader awareness due to to the internet, media coverege etc. When I was growing up there was no way for us to contact each other.

More sensory bombardment impairing more people to the point of meeting the diagnostic criteria.

Much more group interaction and multitasking skills needed today meaning some that could function in society with difficulty in the past can’t now.

Could it also have to do with increased urbanisation? In Canada, at least 80% of the population lives in cities nowadays. But, it's been said that city slickers aren't as happy as their country counterparts, and have more trouble with stress and ainxiety. No wonder New Yorkers always seem to be in a hurry.

What I'd like to know? Are folks like the fictional Sheldon Cooper becoming more common? People who are smart enough to hold good full time jobs so that they may not be "officially" diagnosed, but it is obvious that they are on the Spectrum.