Asperger Syndrome in Females: An Underdiagnosed Population


Asperger syndrome (AS) is an Autism Spectrum Disorder (ASD) characterized by significant impairments in social interaction, and rigid, stereotypical, or repetitive behaviours that exist alongside normal language and cognitive skills (Fitzgerald & Corvin, 2001). Researchers often use the terms Asperger syndrome and high-functioning autism interchangeably (Attwood, 2006), and so for the purposes of this paper, Asperger syndrome will encompass both diagnoses, and assume an IQ in the normal range, i.e., > 70. The ratio of males to females with AS is currently about 10:1, and on average, boys are referred ten times more often for diagnostic assessment (Wagner, 2006). Overall, the lack of knowledge about girls and women with AS is mirrored by a relatively small amount of empirical research dedicated to this population (Thompson, Caruso, & Ellerbeck, 2003). Much of the available literature includes clinical observations, case studies, and anecdotal evidence.

Some feel that the uneven gender ratio is a natural reflection of biological sex differences. Jones, Skinner, Friez, Schwartz, and Stevenson (2008) propose a sex-linked genetic cause, and argue that the single X chromosome in males is inherently vulnerable, creating a lower threshold of susceptibility to AS. Alternatively, Baron-Cohen and Wheelwright (2004) hypothesize that gender differences in brain specialization may explain the male-dominated ratio, and contend that while females are naturally better at empathizing, males tend to think in a systemizing way. They conceptualize Asperger syndrome as an extreme systemizing form of the normal male brain that may develop due to high levels of testosterone exposure in utero. The question arises, however, as to what extent sex differences are biological, or influenced by sociocultural factors.

In contrast to the researchers that find support for the current gender ratio, many believe it is inaccurate (e.g., Attwood, 2006; Rastam, 2008). Thompson et al. (2003) claim that a long-standing sex bias in AS research has resulted in diagnostic criteria too dependent on a male prototype, and point out that 80% of all ASD study samples have been male, on average. They suggest further that our present knowledge about ASD is actually knowledge about males with ASD. Nyden, Hjelmquist, and Gillberg (2000) highlight comparable issues in the diagnostic criteria for Attention Deficit Hyperactivity Disorder (ADHD), while Rastam (2008) parallels the development of criteria for clinical eating disorders, based largely on the signs and symptoms prevalent in females. Hully and Lamar (2006) suggest that overdependence on a male prototype means that traits in females must appear exaggerated for diagnosis. Ironically, researchers are finding it difficult to obtain samples on females that are large enough to allow for comparison by sex (Hartley & Sikora, 2009). This paper will explore how psychiatric disorders may mask AS in females, gender differences in phenotypic expression that can cause diagnostic confusion, and the attitudes and behaviour of others toward females with AS that can contribute to a missed diagnosis.

Several disorders have the potential to overshadow Asperger syndrome in females including depression, ADHD and Anorexia Nervosa (AN) (Hartley & Sikora, 2009; Rastam, 2008; Ryden & Bejolet, 2008). Researchers feel that the risk of misinterpreting signs and symptoms is strong, and could lead to misdiagnosis, or failure to recognize AS as the primary disorder (Cooper & Hanstock, 2009; Ryden & Bejolet, 2008). Hully and Lamar (2006) observed that as girls grow older, the presenting problem is less often associated with a developmental disorder, and stress that clinicians must take a detailed patient history to rule out AS in females. Accordingly, Ryden and Bejolet (2008) found that adult women with AS comprised a large portion of the psychiatric outpatients that they studied (39 females and 44 males), and speculate that many females do not receive an accurate diagnosis until they seek treatment for a comorbid disorder.

Although the gender ratio for childhood depression is 1:1 in the general population, by adolescence, females are three times more likely to receive a diagnosis of depression (Cooper & Hanstock, 2009). In fact, Ryden and Bejolet (2008) found a history of depression most often in patients that had not received a diagnosis of AS until adulthood. This could underscore a lack of awareness of how Asperger syndrome looks at different ages, and in females. Symptoms that often cause diagnostic confusion include a flat affect, minimal facial expressions, flat intonation in speech, irritability, and social isolation (Cooper & Hanstock, 2009). Hartley and Sikora (2009) found that girls with ASD, as young as 1.5 years of age, displayed an anxious or depressed affect more often, which lends support to this idea. In addition, Cooper and Hanstock (2009) discovered that Jane, initially referred for confirmation of a mood disorder, had a stable baseline mood over a long period. They concluded that failure to recognize significant social impairments, along with a flat affect and monotone voice, a number of school changes, and normal IQ and language skills, resulted in a misdiagnosis of depression.

Holtmann et al. (2007) found that females, across the entire sample that they studied, had significantly more attention difficulties than males, and similarly, Nyden et al. (2000) established that girls, aged 8 to 12 years, had greater impairment on the Freedom from Distractibility subscale than boys in the same age range. Greater attention difficulties in girls and women suggest that a misdiagnosis of ADHD may occur more often in this population. In accordance with this, Ryden and Bejolet (2008) assert that the lack of common sense and social disinhibition inherent in AS could be mistaken for impulsiveness, further increasing the likelihood of an incorrect ADHD diagnosis.

Ryden and Bejolet (2008) also discovered that adult female patients with Asperger syndrome scored higher on scales measuring borderline and passive aggressive traits, and mood instability, despite presenting with the same core AS features as males. Holtmann et al. (2007) uncovered a similar trend in their analysis of a matched subgroup of males and females.

Although core impairments were also equal in both genders, girls scored higher on scales measuring peer relationship impairments, social immaturity and dependency, as well as compulsive and bizarre behaviour, with older females scoring the highest. Similarly, Cooper and Hanstock (2009) found that Jane’s social impairments and deviance from her peers were more obvious as she grew older.

These findings suggest that if a clinician fails to notice a girl’s severe social difficulties in childhood, the result could be an incorrect diagnosis of BPD later on. Likewise, Ryden and Bejolet (2008) state that undetected AS might exist in a subgroup of older females diagnosed with BPD, which further emphasizes the importance of taking a detailed patient history when considering diagnosis. In addition, they stress that concepts of personality disorder and abnormal personality traits are difficult to separate in Asperger syndrome, and propose that a different model is needed to explain “odd personality” in this population.
Written by A. MacMillan

Aging and Autism – Insights from the Perspectives of Adults with High Functioning Autism/Asperger Syndrome

Art by Maria Zeldis

Art by Maria Zeldis

Over a year ago I had the privilege of being part of a research team exploring the experiences of adults with High Functioning Autism/Asperger’s Syndrome, within our community. Whilst most of the data generated in the early stages of the research was  considered comparatively raw, I never the less, picked up on some of the less anticipated and therefore more qualitatively unique themes that emerged from within the data.

One of those themes concerned the prospects of aging  for those with High Functioning Autism.

I nominate this as a unique theme because it may very well represent the first time that any research project has stumbled upon the issue of aging as  derived specifically from the perspectives of adults with high functioning autism themselves.

As an Autism parent I am well versed in the realm of potential fears  that we hold for our children’s care as they enter into adulthood.

The ever-present concern of what ‘will happen in the future’  forms not only a salient question for parent carers, but  is also, according to the words of many with High Functioning Autism,  increasingly forming an even more salient and potentially frightening question  for those with high functioning autism themselves.

‘What will happen to me when I can no longer remain independent within my own home?’

The level of concern that adults with high functioning autism express when discussing the issue of their own aging creates  a disturbing picture of  just what the reality of aged care may well represent for them.

A picture that from my perspective, demands that a clearer understanding of how adults with high functioning autism relate to the current structure of the aged care system and its  facilities, be obtained and worked upon as a matter of policy.

For example, could an adult with high functioning autism, who has been independent prior to old age, cope with having to adapt to the routine of a nursing or aged care home?

Would they cope with being told not only when to eat but what to eat?

Would they deal well with a constant intrusion on their privacy by well-meaning staff?

Many of the adults spoken to described the current version of aged care on offer to them as a ‘nightmare’ of epic proportions.

This descriptor was especially strong among those whose ability to lead  an independent life had been premised largely on their ability to remove themselves from the presence of others in order to eliminate stress when necessary.

To me such descriptions pose some serious questions around aging and autism that need to be addressed. For example :

What is on offer for adults with High Functioning  Autism who have extreme sensory sensitivities to noise and/or the presence of others?

What would happen in the event of a meltdown in such an environment?

Are aged care facilities really geared up for handling the multiple sensory issues and sensitivities that adults with High Functioning Autism can experience?

Research is increasingly showing that when it comes to the concerns of those with High Functioning Autism, we are no longer just  talking about the concerns of a small group of people who crave solitude.

Rather, research is beginning to uncover  the legitimate concerns of an increasingly growing number of adults who not only do not want to be placed in aged care facilities, but who doubt their very ability to survive in them.

These are people whose very quality of life can sometimes depend on their capacity to remove themselves from the presence of others. Their concerns are real and they need to be addressed.

Is this something any of you have thought about?

Have you read any articles that tackle the issue of aging and autism?

If so I’d be extremely interested in hearing more about your views on aging.

Thank you for taking the time to  read this post.