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Editorial                                                                                                                                             Open Access

## Special Issue on the Topic of Autism Spectrum Disorder

Angela M. Reiersen 1 and Sven Bölte 2

1 Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri, USA 2 Department of Women's and Children's Health, Neuropsychiatry Unit, Center of Neurodevelopmental Disorders (KIND), Karolinska Institutet, Stockholm, Sweden

## *Corresponding author: reiersea@psychiatry.wustl.edu

For this first special issue of the Scandinavian Journal of Child and Adolescent Psychiatry and Psychology (SJCAPP) ,  we  invited  authors  to  submit  papers about autism spectrum disorder (ASD). The topics of the final accepted manuscripts include the replication of some previous findings as well as new information in understudied areas.

One  important  and  inadequately  studied  area  is gender differences in the presentation  of  ASD (1). Some  investigators  have  expressed  concerns  that high-functioning girls with ASD may be underidentified  as  a  result  of  differences  in  their symptom presentation (1-3), and sex differences in ASD symptom presentation have also been suggested  by  some  studies  of  lower-functioning individuals  (4).  Because  the  type  and  severity  of specific  ASD-related behaviors may be different in females  with  ASD  as  compared  with  males  with ASD-for  example,  restricted-repetitive  behaviors (RRBs)  may  be  less  severe  in  girls-it  has  been suggested that new assessment methods are needed to  detect  the  types  of  ASD  symptoms  that  most commonly occur in females (1-3).

In  the  current  special  issue,  Nguyen  and  Ronald (5) compare ASD symptom presentation and other characteristics of low-functioning girls with ASD (n = 27) with those of typically developing (TD) girls (n  =  17)  and  also  with  those  of  low-functioning boys  with  ASD  (n  =  27).  The  TD  girl  group  was younger  (mean  age,  10  years)  than  the  other  two groups (mean ages, 15 years and 14 years for girls and boys, respectively) because the ASD groups had relatively  low  IQs  and  groups  were  matched  for mental age. The authors found the ASD symptom presentation of low-functioning boys and girls with ASD  to  be  largely  similar,  but  the  data  do  show trends  that  suggest  that  girls  with  ASD  may  have lower scores for many aspects of RRBs and higher scores for self-injurious behavior as compared with boys with ASD. These possible differences were not statistically  significant  after adjustment for multiple testing,  but  they  may  be  worth  further  study  in larger samples. Boys with ASD scored significantly higher  than  girls  with  ASD  or  TD  girls  on  a  test intended to measure attention to detail (the Wechsler  Intelligence  Scale  for  Children,  Revised, or  the  Wechsler  Abbreviated  Scale  of  Intelligence block design task), which suggests that any relative strength  on  the  block  design  task  in  children  with ASD versus TD controls may be unique to males. Further studies with larger samples and the inclusion of a control group of TD boys would help to clarify whether this sex difference in block design performance  is  related  to  sex  differences  in  ASD presentation  or  to  an  overall  tendency  for  males (with or without ASD) to perform relatively well on this task.

Although  Nguyen  and  Ronald  focused  on  lowfunctioning children and adolescents (i.e., those 7 to 19  years  old)  with  ASD,  it  is  also  important  to examine the presentation of ASD among females at older ages and  in those with higher levels of cognitive functioning. Trubanova and colleagues (6) present  a  case  series  of  high-functioning  young adult females with ASD to illustrate some characteristics that may contribute to the underidentification  of  ASD  in  females.  Although these  young  women  with  ASD  are  clearly  socially impaired, they may have high interest in friendships, and they may  even become  hyper-focused on aspects of friendship and social relations in a stereotyped  manner,  similar  to  the  way  in  which boys  with  ASD  may  focus  on  non-social  special interests.  This  case  series  also  illustrates  that  some young  women  with  ASD  may  have  borderline personality  disorder  traits  and  self-harm  behaviors. The  observation of  self-harm  behaviors  among young  women  with  ASD  is  consistent  with  the possible trend toward increased self-injury behaviors seen among girls in Nguyen and Ronald's study  that  was  just  described.  This  observation  is also  of  interest  in  the  context  of  some  recent literature regarding attention-deficit/hyperactivity disorder (ADHD) in females. One recent longitudinal study of girls with ADHD demonstrated that these individuals are at high risk for suicidal and self-injury behaviors as they mature into  adolescence  and  young  adulthood  (7).  Given the frequent co-occurrence of ADHD with ASD (8) and  the  evidence  for  a  strong  association  between RRBs and impulsivity (9) in population-based samples,  it  would  be  of  great  interest  for  future studies to investigate whether the risk for self-injury in  girls  with  ASD  is  increased  by  the  presence  of ADHD symptoms and whether girls  with  ADHD have a higher risk for self-injury when they have cooccurring  ASD.  Additional  research  is  needed  to confirm whether the patterns of behavior illustrated in  this  case  series  are  generally  more  common among females with ASD as compared with males with ASD.  However,  the  case  series  itself has clinical implications, because it illustrates how RRBs in females may be missed in patients in whom the topics of special interest or the characteristics of the RRBs  are  qualitatively  different  as  compared  with the classic descriptions of ASD-related behavior in males.

Another topic of recent focus in the  ASD literature is the transition from  adolescence to adulthood,  including  the  seeking  of  independence and productivity through employment (10). In many cases, young people with ASD receive much of their treatment and services through their school systems, so  they  may  suddenly  be  without  resources  after they  finish  high  school.  In  the  United  States,  the National  Longitudinal  Transition  Study-2  showed that  employment  outcomes  of  young  adults  with ASD who were 21 to 25 years old were worse than those  of  young  adults  with  other  developmental disabilities who  had received special education services during high school (10). The article in this issue  by Kirchner  and  colleagues (11) explores factors that may facilitate or interfere with satisfactory  employment  experiences  among  young adults  with  ASD.  Kirchner  and  colleagues  found that  the  majority  of  high-functioning  adults  with ASD  report  that  it  is  useful  for  employers  and colleagues  to  be  aware  of  their  ASD  diagnoses. Some  of  the  more  common  interfering  factors included  sensory  sensitivities  in  the  workplace  and mental underload. In addition, the authors' findings suggest  that  many  young  adults  with  ASD  may benefit  from  working  in  an  area  related  to  their special interests. This article may help to inform the development  of  improved  work  environments  for individuals  with  ASD,  which  may  then  help  these individuals to use their strengths and special interests to succeed in the workplace.

A relatively  new  area  of  ASD  research  relates  to substance use and substance use disorders. Although substance use seems unlikely  among severely  affected  low-functioning  individuals  with ASD who may not have the social or language skills necessary to obtain substances on their own, higherfunctioning  forms  of  ASD  have  now  been  well recognized  for  years,  and  it  is  unclear  whether individuals with these variations have a high or low risk of substance use as they move into adolescence and adulthood. Existing research has suggested that ASD  may  actually  be  protective  against  substance use in adolescents (at least as compared  with individuals  with  other  psychiatric  diagnoses)  and that  adolescents  with  ASD who  do  use substances tend  to  also  have  co-occurring  ADHD  diagnoses (12). This has not previously been studied with large epidemiological samples of adolescents. In the current  issue  of SJCAPP, Mulligan  and  colleagues (13) examine rates of parent-reported substance use in  a  population-based  large  sibship  sample.  The authors found evidence that adolescents with clinically  elevated  ASD  symptoms  (but  without ADHD) are not at a statistically significant increased risk for alcohol or tobacco use as compared  with  controls  without  ASD  or  ADHD. However, these adolescents are at increased risk for other  drug  use  as  identified  by  a  Child  Behavior Checklist (14) item regarding the use of drugs (other than alcohol and tobacco) for non-medical purposes.  Adolescents  with  a  combination  of  high levels  of  ASD  symptoms  and  ADHD  were  at elevated  risk  for  alcohol,  tobacco,  and  other  drug use. Although the quality of data for this study was not  ideal  (i.e.,  the  only  measures  of  substance  use were  three  parent-report  Child  Behavior  Checklist items), the results suggest that clinicians should not assume that high-functioning patients with ASD are at  low  risk  for  substance  use,  especially  when  they also have co-occurring ADHD. This article suggests a need for the further study of factors that influence risk for substance use and its progression to dependence among  high-functioning adolescents and  adults  with  ASD.  In  fact,  there  is  already  one recent  population-based  study  that  involved  more detailed  substance use data; its results showed that the presence of elevated ASD traits does indeed put individuals  at  risk  for  alcohol,  tobacco,  and  drug dependence during adulthood, even after controlling for ADHD symptoms (15).

In summary, the current issue of SJCAPP focuses on  a  number  of  timely  topics  related  to  ASD. Further  work  is  needed  to  clarify  sex  differences with  regard  to  ASD  risk,  symptom  presentation, comorbidity, and response to treatment; to explore the  vocational  experiences  and  employment  needs of individuals with ASD who are transitioning from adolescence to adulthood; and to determine whether high-functioning individuals with ASD will benefit  from  specialized  substance  use  prevention and  treatment  interventions.  Beyond  the  scope  of the  articles  in  this  special  issue  are  many  other expanding areas of ASD research that are worthy of further study, particularly in the realms of genetics, brain mechanisms, and new treatment interventions for  ASD.  We  hope  that SJCAPP will  have  the opportunity to help disseminate some of this important work.

## References

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