WASHINGTON – The new Diagnostic and Statistical Manual of Mental Disorders criteria for autism spectrum disorder might significantly affect the diagnosis of ASD in very young children, a retrospective analysis has shown.
Only 35% of a sample of children diagnosed with ASD before age 3 based on DSM-IV criteria retained the diagnosis when DSM-5 criteria were applied.
"The strict nature of the criteria in a population whose symptomatology may be emerging is at odds with an early diagnosis model," said Dr. Lisa H. Shulman, director of the Rehabilitation, Evaluation and Learning for Autistic Infants and Toddlers program at the Albert Einstein College of Medicine, New York.
"Clearly, prospective studies on the impact of DSM-5 on early diagnosis are needed," she said at the annual meeting of the Pediatric Academic Societies (PAS).
Studies of the impact of the new criteria on diagnosis of ASD have focused on school-age children. Dr. Shulman and her coinvestigators looked at younger children, examining all the children who had been diagnosed with ASD by 3 years of age based on a multidisciplinary evaluation at their center during 2003-2010. Diagnoses were based on DSM-IV criteria. Childhood Autism Rating Scale (CARS) scores also were examined, however, and cognitive testing was completed in some of the children.
To determine how many of the children would retain the diagnosis using DSM-5 criteria, an algorithm was used to map data from the DSM-IV and the CARS scores onto the DSM-5 criteria. Of 237 children who had been diagnosed with ASD by age 3 at the inner-city early intervention program, only 84 children (35%) met the criteria for ASD using the DSM-5 criteria.
The children whose diagnosis was retained using DSM-5 criteria were significantly more likely to have had higher CARS scores (38.3 vs. 33.5), which are indicative of more severe social impairment. They also had a trend toward lower cognition, with 34% of those with an IQ of less than 70 diagnosed under DSM-5 criteria, compared with 12% with IQ greater than 70, Dr. Shulman reported.
The potential of the DSM-5 criteria to diagnose the more impaired children preferentially might present an obstacle to diagnosis for the children most likely to benefit from early intervention – those with the mildest symptomatology, she said.
To be classified as having ASD using the DSM-5 criteria, a child has to meet each of three categories of social-communication criteria: deficits in social-emotional reciprocity; deficits in nonverbal communicative behaviors used for social interaction; and deficits in developing and maintaining relationships and adjusting behavior to social contexts appropriate to developmental level.
In addition, a child also must have at least two out of four types of restrictive/repetitive patterns of behavior, interests, or activities: stereotyped or repetitive speech, motor movements, or use of objects; excessive adherence to routines or ritualized patterns of verbal or nonverbal behavior; highly restricted fixated interests that are abnormal in intensity or focus; and hyper- or hyporeactivity to sensory input or unusual interest in sensory aspects of the environment.
The group of social-communication criteria least commonly met by the children in the study was "deficits in developing relationships." The specific criteria included in this group – difficulty sharing imaginative play, difficulty in making friends, and absence of interest in people – are especially challenging to apply to and evaluate in young children, said Dr. Shulman, associate professor of pediatrics at Albert Einstein.
Only 61% of the children met at least one of the criteria in this category. "For very young children, where we’re not in the situation to have information or parental concerns regarding making friends, we’re left with ‘absence of interest in people’ – a pretty extreme criteria," she said.
Three of the four "restrictive/repetitive" interests were reported in less than half of the children. While repetitive use of objects or motor movements was present in 89%, excessive adherence to routines was reported in 28%, restricted interests in 41%, and hyper-hypo sensitivity in 25%.
The low rate of hyper-hypo sensitivity was "interesting," Dr. Shulman noted, as inclusion of these sensitivities is new to the manual and "thought to be a nod to young children, who often have more of these symptoms." Consideration of CARS scores in the analysis provided some degree of a measure for these sensitivities, she noted.
The DSM-IV described five different disorders under the general category of "pervasive developmental disorders," for which diagnoses could be made based on 12 criteria; this allowed for any of 2,688 combinations of criteria to arrive at a diagnosis. Under the new version, which describes 1 disorder based on 5 out of 7 criteria being met, "only 12 combinations of criteria can arrive at a diagnosis," Dr. Shulman noted.