Timeliness of Autism Spectrum Disorder Diagnosis and Use of Services among U.S. Elementary School-Aged Children

Abstract

Objective

This study assessed the relationship of timeliness of ASD diagnosis with current use of ASD-related services in a nationally-representative sample of U.S. children.

Methods

The CDC’s Survey of Pathways to Diagnosis and Services was used to assess experiences of 722 children age 6–11 with ASD. Bivariate and multivariate associations between age and delay in ASD diagnosis and use of health services were explored. Older age of diagnosis was defined as diagnosis at age 4 years or older. Delay in diagnosis was defined as time ≥2 years between first discussion of concerns with provider and ASD diagnosis. Health services included current use of behavioral intervention therapy (BI), school-based therapy, complementary/alternative medicine (CAM), and psychotropic medications.

Results

Mean age of ASD diagnosis was 4.4 years, and mean diagnostic delay was 2.2 years. On adjusted analysis, diagnosis at ≥4 years old was associated with lower likelihood of current BI or school-based therapy use. Diagnosis at ≥4 years old was also associated with higher likelihood of current psychotropic medication use. Likelihood of current psychotropic medication use increased with older age of ASD diagnosis. A ≥2 year delay in diagnosis was associated with higher likelihood of current CAM use. Likelihood of current CAM use increased as delay in diagnosis got longer.

Conclusions

Both older age of diagnosis and longer delay in diagnosis were associated with different health services utilization patterns among younger children with ASD. Prompt and early diagnosis may be associated with increased use of evidence-based therapies for ASD.

Introduction

Autism spectrum disorder (ASD) is a neurodevelopmental condition characterized by atypical social communication and interaction, coupled with restricted and/or repetitive behaviors and interests (1). ASD is common, affecting one in 68 U.S. children (2). Signs of ASD usually develop in the first two years of life (3, 4). Though diagnosis can usually be made by age two, average U.S. age of diagnosis is over four years (2). Delay between emergence of signs and ASD diagnosis is noteworthy because early intensive treatments may have long-term benefits for child functioning and family life (5–8).

Primary care providers (PCPs) are essential to early ASD detection, since they are in frequent contact with parents during a child’s first years. Nonetheless, some PCPs give false reassurance (9) or fail to direct families to diagnostic resources when valid parental concerns exist (10, 11). Although major pediatric organizations recommend routine ASD screening (12, 13), only around half of PCPs screen for ASD (14–16). Even when screening occurs, delays between initial conversations with providers and ASD diagnosis are common. Delays may relate to lack of family knowledge about ASD and the healthcare system, disability stigma, health- and educational-system communication or authorization difficulties, long waiting periods for evaluations, and geographic or transportation barriers (17–19).

When concerns for ASD exist, a child can be referred for treatment services. Some services target core ASD features (e.g., promoting social skills, reducing inflexible behaviors). Other services address ASD comorbidities (e.g., attentional problems, anxiety) (20). ASD-related service use varies by type (e.g., occupational therapy, prescribed medication) and amount (e.g., hours of services per week, medication dose) (21). There is no “best” combination of therapy for ASD in early childhood; however, behavioral intervention (BI) therapy directed at core ASD symptoms has strongest evidence of effectiveness (6–8). Other therapies, such as sensory integration therapy, complementary and alternative medicine (CAM) approaches and/or psychopharmacological treatments for ASD are more controversial (8, 22, 23).

Service use may correspond with timeliness of ASD diagnosis. For instance, it is possible that families experiencing long ASD diagnostic delays are more likely to use CAM, especially CAM that is easily purchased (e.g., supplements). Families may experience delays due to misdiagnosis (24), and therefore may use therapy or pharmacological treatments for other conditions (e.g., ADHD). Timeliness of diagnosis may affect families’ use of government-funded services (e.g., Part C Early Intervention) that depend on the child’s age (25). As pediatric organizations press for early ASD identification (12) it is important to determine whether timely diagnosis is associated with subsequent ASD-related service use. Thus, this study aimed to assess the relationship between ASD diagnostic age and delay with current health services use in a nationally-representative sample.

Methods

Data source and study sample

Data were drawn from the Center for Disease Control’s 2011 Survey of Pathways to Diagnosis and Services (“Pathways”). Pathways was a follow-back to the 2009/10 National Survey of Children with Special Health Care Needs (NS-CSHCN) (26), a nationally-representative, parent-reported telephone survey of CSHCN according to the CSHCN Screener (27, 28). NS-CSHCN’s response rate was 25.5% (29). Parents whose children had ASD, intellectual disability (ID) and/or developmental delay (DD) in the NS-CSHCN and were age 6–17 in 2011 were re-contacted to participate in Pathways. Pathways had a telephone and written component; this analysis only concerns the telephone component. 71% of eligible families were successfully re-contacted, and 87% of those agreed to participate in Pathways (N=4,032) (30). Methodology of NS-CSHCN and Pathways has been described and is available on the National Center for Health Statistics’ website (27, 29, 30).

In Pathways, we assessed experiences of elementary school-aged children (6–11 years) with current ASD. Children with ID and/or DD but not ASD, and children with past but not current ASD were excluded (N=2,098). Children age ≥12 (N=698) were excluded due to fewer ASD treatment guidelines in this group and recall bias concerns (e.g., parents of adolescents with ASD may not remember child’s diagnosis age). The survey was approved by the National Center for Health Statistics’ Institutional Review Board.

Variables

This study used two measures of timely ASD diagnosis. The first (“Age of ASD Diagnosis”) was based on responses to: “How old was your child when you were first told [s/he] had autism or autism spectrum disorder [by a healthcare provider]?” The second measure (“Delay in ASD Diagnosis”) was calculated as the difference in child age between when a parent “first talked with a doctor or healthcare provider about [developmental] concerns” and the age of ASD diagnosis. Since Pathways recorded age in months up to 36 months and in years thereafter, we standardized Age of ASD Diagnosis and Delay in ASD Diagnosis values to years by rounding to whole completed years (e.g., 6 months or 11 months=0 years; 15 months or 23 months=1 year). We rounded for three reasons: first, most parents of children >36-months would likely also do so (e.g., parents would report a child who is three years and 10 months old as age 3, not age 4). Rounding also kept age measurements uniform across ages, which is critical since many time intervals we examined spanned the 36-month time-point. Finally, rounding accounted for parents having difficulty remembering the exact month of events that occurred years prior.

Analyses treated age and delay outcomes as both dichotomous and continuous variables. In dichotomous analyses, older ASD diagnosis age was defined as ≥4 years based on mean sample diagnosis age (4.4 years). Also, clinically it would be possible to diagnose most children with ASD by age four (2). We similarly defined longer ASD diagnostic delay as ≥2 years between age of first provider conversation and diagnosis. We dichotomized delay at two years based on mean sample delay (2.2 years). Also, clinically this would be a long delay regardless of when parents initially expressed concerns: in most cases early signs of ASD are present by age two (31–33). In analyses where age or delay was treated as continuous, the variable was considered in whole years only.

Child and family factors previously associated with age of ASD diagnosis and ASD-related health services utilization served as covariates (34, 35). Factors included child age, gender, race/ethnicity, health insurance type, functional limitations status, household income relative to federal poverty level (FPL), parent education, census region, and family structure. FPL was defined in 2011 as $22,350 per family of four (36). Insurance was categorized as “any private insurance” or “public only or uninsured,” as many children had both private and public insurance and only 16 were uninsured. Functional limitations status, a sensitive indicator of elevated health services use, was used as a severity marker (37), and was defined as an affirmative response to the CSHCN Screener functional limitations items (e.g., “child is limited in any way in his/her ability to do things most children of the same age can do” due to “any medical, behavioral, or other health condition that is expected to has lasted or is expected to last 12 months or longer”) (28).

We studied four measures of ASD-related health services use; each has previously varied among children with ASD (35, 38, 39) and/or related conditions (40). Psychotropic medication use was identified if the child was taking any psychotropic medication “to meet his/her developmental needs” currently on a regular basis, including stimulants, antidepressants, anxiolytics, mood stabilizers, anti-seizure medications, antipsychotics, and sleep medications. BI use was defined as whether the child was using “behavioral intervention or modification services to meet his/her developmental needs” at least once per week currently on a regular basis. CAM use was defined as whether the child currently used “any type of alternative healthcare or treatment to meet his/her developmental needs” on a regular basis. School-based therapy use was defined as whether the child used social skills training, occupational, physical or speech/language therapy at school, currently on a regular basis.

Statistical analysis

Descriptive statistics were computed, assessing sample socio-demographic characteristics. Chi-square tests were used to compare proportions of children receiving the four ASD health services (psychotropic medications, BI, CAM, and school-based therapy) by socio-demographic characteristics.

To examine primary outcomes, chi-square tests were computed, comparing proportions of children receiving each of the health services, in children with older (≥4 years) versus younger (<4 years) diagnostic age, as well as longer (≥2 years) versus shorter (<2 years) diagnostic delay (Table 2). Logistic regression models were fit to examine unadjusted and adjusted associations between diagnostic age and delay with use of the four health services, controlling for all child and family covariates. Logit models were fit to examine ASD diagnostic age and delays as continuous variables in association with the four health services, controlling for the same covariates (Table 4). Sensitivity analyses tested if the interaction between diagnostic age and delay modified associations with health services use. Analyses additionally examined if the relationship of ASD diagnostic age and delay with services use was modified by length of ASD diagnosis (i.e., difference between child age of ASD diagnosis and child age when surveyed), by functional limitations status, or by comorbid ID diagnosis. Analyses were performed in Stata 13.1 (College Station, Texas), using survey weights to account for Pathways’ complex sampling design.

Table 2.

Weighted percentages with 95% confidence intervals of health services receipt by diagnostic delay and socio-demographic factors among U.S. children with ASD aged 6–11 years

	≥ 1 or more psychotropic medication type(s) used currently on a regular basis	Current use of behavioral intervention or modification at least once per week			Current use of complementary/alternative health care		≥ 1 School-based therapy
	Weighted %	95% CI	Weighted %	95% CI	Weighted %	95% CI	Weighted %	95% CI
Overall percentage	49	41.9–55.1	32	26.4– 38.3	16	12.4–21.3	79	72.7–83.9
ASD diagnostic age and delay
Diagnosed < 4 years old	31	22.4–40.5	44	34.2–53.5	20	13.4–29.8	90	82.6–94.1
Diagnosed ≥ 4 years old	60	51.3–67.2	25	18.6–33.0	14	9.6–19.7	72	63.3–79.2
Diagnostic delay < 2 years	41	32.2–50.3	39	30.7–48.4	11	7.7–15.6	83	74.4–89.1
Diagnostic delay ≥ 2 years	55	45.6–64.3	26	19.2–34.1	21	14.3–28.9	75	66.3–82.5
Sociodemographic factors
Age
6–8 years	38	28.4–48.2	35	26.3–45.3	18	11.1–26.9	81	70.5–88.6
9–11 years	56	47.4–64.0	30	23.1–38.2	16	11.0–21.6	77	69.5–83.7
Gender
Male	50	42.5–56.8	32	25.5–38.7	16	11.5–20.8	80	73.6–85.9
Female	44	28.0–60.8	34	21.4–48.2	20	10.2–35.0	71	56.0–81.7
Race/ethnicity
White, non-Hispanic	50	42.2–57.3	41	33.3–48.2	18	13.1–23.1	76	68.6–82.4
Hispanic	47	28.6–65.4	17	7.8–34.4	18	7.2–38.3	78	56.2–90.6
Black, non-Hispanic	49	25.8–71.9	23	10.0–44.8	12	3.4–33.8	89	70.7–96.6
Other race, non-Hispanic	47	27.5–67.1	18	9.5–31.4	12	5.6–23.6	86	66.1–94.8
Health insurance status/type
Any private insurance	47	39.1–54.6	31	24.5–38.1	16	11.5–22.7	78	70.1–83.9
Public only or uninsured	50	37.3–61.9	35	24.6–48.0	17	10.4–26.0	80	68.3–88.2
Functional limitations
No	44	33.7–55.1	26	17.4–35.8	13	7.9–21.1	66	54.6–76.0
Yes	51	42.8–59.5	36	28.9–44.3	18	13.1–25.1	87	81.6–91.3
Household income
0%–99% FPL	68	50.9–80.6	28	14.8–47.5	20	9.8–35.4	72	52.6–85.4
100%–199% FPL	49	34.8–63.8	33	21.2–46.9	10	5.5–18.3	91	83.2–95.2
200%–399% FPL	42	32.0–52.3	37	27.8–47.3	15	8.9–22.8	85	75.5–91.0
≥400% FPL	43	31.8–54.8	28	19.4–38.8	21	13.2–32.9	66	52.9–77.1
Parent educational attainment
High school or less	56	40.0–70.4	28	16.0–44.1	6	3.0–12.5	92	81.1–97.2
More than high school	46	39.2–53.2	33	27.2–40.0	20	14.7–25.7	75	67.5–80.7
U.S. census region
Northeast	37	24.2–51.0	46	33.1–59.5	12	6.8–21.2	87	76.1–93.0
Midwest	56	43.2–67.6	38	26.1–51.1	17	9.9–28.0	76	61.4–86.1
South	54	42.1–65.4	23	15.6–33.6	11	6.5–17.4	79	70.1–85.9
West	40	28.0–54.1	27	17.5–39.3	29	17.4–44.3	75	57.3–87.3
Family structure
2 parent biological/adopted	43	35.0–50.4	34	27.4–41.7	18	12.7–23.7	78	70.9–84.2
Single mother	56	39.8–71.7	35	21.1–53.0	20	9.8–36.3	78	59.4–89.3
Other	58	41.2–73.1	22	12.1–36.0	10	4.9–18.2	84	67.6–92.6

Abbreviations: ASD, Autism Spectrum Disorder; CI, Confidence Interval; FPL, Federal Poverty Level

Table 4.

Associations of ASD age of diagnosis, diagnostic delay, and length of diagnosis with health services utilization among U.S. children with ASD aged 6–11 years: Adjusted logit regression model coefficients, 95% confidence intervals and p-values

	≥ 1 or more psychotropic medication type(s)			Current use of behavioral intervention or modification			Current use of complementary alternative health care			Current use of ≥ 1 school-based therapyb
ASD diagnostic age and delay	Coefficienta	CI	p	Coefficienta	CI	p	Coefficienta	CI	p	Coefficienta	CI	p
Age of ASD diagnosis	.38	.15 to .61	.001	−.22	−.45 to .02	.07	−.18	−.50 to .13	.27	−.22	−.53 to .09	.17
Delay in ASD diagnosis	−.03	−.22 to .15	.72	.04	−.14 to .23	.64	.32	.08 to .56	.009	.05	−.15 to .26	.61

Note: Models controlled for child gender, race/ethnicity, highest level of parent education, household income relative to the federal poverty level, census region, health insurance status/type, family structure, and functional limitations status

Abbreviations: ASD, Autism Spectrum Disorder; CI, 95% confidence interval

Results

Of 722 households meeting inclusion criteria, mean child age was 8.9 years. Most children (73%) were White non-Hispanic, privately insured (69%), and above 200% FPL (65%). 63% of children had functional limitations (Table 1). On average, parents first discussed developmental concerns with a provider when the child was 2.1 years old. Mean ASD diagnosis age was 4.4 years, leading to a mean diagnostic delay of 2.2 years (Figure 1). School-based therapy was the most frequently used health service (79%). 49% of children used psychotropic medications, 32% used BI, and 16% used CAM (Table 2).

Table 1.

Socio-demographic characteristics of U.S. children with ASD aged 6–11 years (N=722)

	Frequency	Mean ± SD/%
Age, years
	722	8.9±1.5
Gender
Female	135	18
Male	586	82
Race/ethnicity
White, non-Hispanic	519	73
Hispanic	73	10
Black, non-Hispanic	47	7
Other race, non-Hispanic	75	11
Health insurance status/type
Any private	487	69
Public only or uninsured	215	31
Functional limitations
No	269	37
Yes	453	63
Household income
0%–99% FPL	106	15
100%–199% FPL	149	21
200%–399% FPL	245	34
≥ 400% FPL	222	31
Parent educational attainment
High school or less	108	15
More than high school	614	85
U.S. Census Region
Northeast	138	19
Midwest	171	24
South	198	27
West	215	30
Family structure
2 parent biological/adopted	507	71
Single mother	106	15
Other	104	15

Abbreviations: ASD, Autism Spectrum Disorder; FPL, Federal Poverty Level; SD, Standard Deviation

Figure 1.

Mean age and delay in ASD diagnosis among U.S. children aged 6–11

Abbreviations: ASD, Autism Spectrum Disorder

When ASD diagnosis age was dichotomized at four years, bivariate and multivariable analyses showed significant associations with psychotropic medication, BI, and school-based therapy use. The strongest association was with school-based therapy use: children with older ASD diagnosis age had lower odds of current school-based therapy use versus children with younger diagnosis age (72% of children diagnosed at ≥4 versus 90% of children diagnosed at <4 years; adjusted odds ratio [aOR]=.38, 95% confidence interval [CI]=.18–.83). BI use was also less likely among children diagnosed at older ages (25% versus 44%, aOR=.55, CI=.31–.97). Psychotropic medication use was more likely among children diagnosed at older ages (60% versus 31%; aOR=3.09, CI=1.77–5.39; Tables 2 and 3).

Table 3.

Unadjusted and adjusted odds ratios with 95% confidence intervals of health services utilization given late diagnosis (age ≥ 4 years) or diagnostic delay ≥ 2 years among U.S. children with ASD

	≥ 1 or more psychotropic medication type(s) used currently on a regular basis					Current use of behavioral intervention or modification at least once per week					Current use of complementary or alternative health care					Current use of ≥ 1 school-based therapyb
	OR	CI	aORa	CI	p	OR	CI	aORa	CI	p	OR	CI	aORa	CI	p	OR	CI	aORa	CI	p
Diagnosed at ≥ 4 years (reference: diagnosed at < 4 years)	3.31	1.92– 5.70	3.09	1.77– 5.39	<.001	.44	.25–.76	.55	.31–0.97	.039	.63	.32– 1.21	.84	.42–1.69	.628	.29	.14– .61	.38	.18–.83	.014
Diagnostic delay of ≥ 2 years (reference: diagnostic delay of < 2 years)	1.77	1.03– 3.03	1.69	.97– 2.94	.063	.54	.32– 0.93	.66	.38–1.13	.131	2.09	1.15– 3.80	2.81	1.50–5.73	.001	.62	.32– 1.23	.59	.30–1.15	.12

Abbreviations: aOR, adjusted odds ratio; CI, 95% confidence interval; OR, odds ratio

^aModels controlled for child age, sex, race/ethnicity, household income, insurance type, census region, functional limitations status, highest parent education level, and family structure.

^bSchool-based therapies included social skills training as well as occupational, physical or speech/language therapy provided at school to children currently on a regular basis.

When ASD diagnosis age was treated as continuous in multivariable models, there was a positive association between increasing age of diagnosis and psychotropic medication use (p=.001). There was a marginal negative association between diagnosis age and BI use (p=.07), and no significant associations with CAM or school-based therapy use (Table 4).

ASD diagnostic delay had a different effect on services use than did ASD diagnosis age. CAM use, which had no significant associations with diagnosis age, was nearly twice as common among children with longer versus shorter delays (21% versus 11%; aOR=2.81, CI=1.50–5.73). When diagnostic delay was treated as continuous, there was a significant association with CAM use: as diagnostic delay increased, the likelihood of current CAM use increased (p=.009). Psychotropic medication use had a significant positive bivariate association with diagnostic delay, but was of borderline significance (p=.063) in multivariable results, and was non-significant when delay was treated as continuous.

We considered whether the relationship between diagnostic delay and services receipt was affected by functional limitations status and found that as diagnostic delay increased, children with functional limitations became significantly less likely than children without functional limitations to receive school-based therapy (p=.04) (Supplemental Figure 1).

Interaction between diagnosis age and delay did not modify services use; that is, the relationship between diagnosis age and services use was not significantly different among those with shorter versus longer diagnostic delays. There was a significant negative interaction between diagnostic delay and ASD diagnosis length according to BI use: as both length of ASD diagnosis and diagnostic delay increased, likelihood of current BI use decreased among children. There were no significant interactions between diagnosis age and functional limitations, comorbid ID and diagnosis age, or comorbid ID and diagnostic delay in terms of subsequent services use.

Discussion

This study’s goal was to investigate whether timeliness of ASD diagnosis was associated with subsequent ASD-related health services use. Since both early and prompt ASD diagnosis are important public health goals (36), we considered timeliness of ASD diagnosis in two ways: if the child was diagnosed at a younger (versus older) age, and if the child experienced a longer (versus shorter) diagnostic delay. Results suggested children diagnosed at older ages were less likely to currently use ASD-related therapy services and were more likely to take psychotropic medication, compared to children diagnosed at younger ages. Results also suggested children experiencing longer diagnostic delays were more likely to use CAM compared to children experiencing shorter delays. Since analyses controlled for current age and functional limitations status, differences are unlikely to be related to age cohort effects or lower ASD severity among children with late or delayed diagnoses. In fact, results revealed children with ASD and functional limitations may be especially likely to receive no therapy services when diagnosis is delayed.

Though the optimal type and amount of ASD therapy remains unclear, there is growing consensus that early therapy benefits children and families (41). It is therefore concerning that nearly a quarter of the elementary school-aged children studied were receiving no school-based therapy, and over half were not receiving BI. When we considered the approximately 50% of children who were ≥4 years at diagnosis, current therapy use was even lower. Instead, children diagnosed at older ages were more likely to receive psychotropic medications, which generally do not treat core ASD features. Similarly, children with long diagnostic delays were more likely to use CAM. Children with long delays and functional limitations (who may have the greatest therapy needs) had some of the lowest rates of school-based therapies. Together, these results suggest families who receive later ASD diagnoses are less likely use evidence-based therapy directed at core ASD symptoms and more likely to use alternative treatments, especially when a child is significantly impaired.

These findings should interest providers and policymakers. Previous research has indicated most parents delay only a few months before talking to providers about developmental concerns; however, substantial delays occur after initial provider conversations (10). This study adds to the literature by suggesting ASD diagnostic delays are also associated with long-term treatment differences. Results suggest that if long-term ASD therapy use is a priority, payers and policymakers may need to proactively accelerate diagnosis by incentivizing screening or enhancing case management of children at high risk for diagnostic delays. From a population standpoint, as children receive earlier ASD diagnoses, payers may expect changes in service use patterns toward more therapy use and less pharmacology.

Though ASD diagnostic delays may play a causal role in subsequent services use, alternative explanations of study findings are plausible. For instance, families who receive a delayed diagnosis may be less connected to the healthcare system for a number of reasons (e.g., skepticism about effectiveness of conventional care, financial or geographic barriers to accessing care), making them less likely to seek conventional services and more likely to pursue CAM. Even if one were to assume later diagnosis causes subsequent decreased conventional service use, the mechanism whereby that occurs is unclear. Pathways did not collect information about what therapy services parents were offered, why parents chose or rejected any particular services, or whether current services were specifically for ASD versus some other developmental/behavioral problem. Parents’ beliefs about ASD may play a role in subsequent treatment decisions (35, 42); research exploring parents’ beliefs regarding treatment or longitudinal studies following families’ treatment decisions may elucidate these findings. Future research should explore why children were using certain therapies at high rates (e.g., psychotropic medications which are not generally indicated for ASD).

The study has other limitations. Pathways is based on parent report; consequently, ASD diagnoses were not verified. Few data exist regarding validity of parent-reported ASD diagnoses; however, national parent-reported surveys have produced prevalence estimates similar to studies that used more rigorous methods of ASD verification (2). There was no way to validate type or frequency of service use, although studies have revealed parents to be reliable sources of medication and health service use in typically-developing children (43–46). Recall bias may also limit findings: parents may have had difficulty recalling the timing of their first conversation with a provider about developmental concerns or timing ASD diagnosis. To limit recall bias and account for imprecise date reporting, this study reported age in years and assessed only elementary school-aged children. Nonetheless, correlations found in the data may be due to biases in parent reporting rather than true associations (e.g., perhaps parents who report earlier ASD diagnoses also more often report certain details about their child’s current therapy compared to other parents). Also, since the study rounded age and delay to whole completed years, findings may underestimate diagnosis age and diagnostic delay for some children.

This study focused on children with ASD, regardless of comorbid ID and/or DD. Children with ASD and comorbid ID and DD may have use different services than other children with ASD (21). Sensitivity analyses did not suggest these were salient to the studied outcomes. We used child current functional status as a covariate in models to adjust for confounding by severity; however, current functional status may have differed from functional status at time of initial provider conversation and/or ASD diagnosis. Finally, the sample from Pathways and the NS-CSHCN could be subject to non-response bias from either survey.

Conclusions

To our knowledge, this is the first study indicating that children diagnosed with ASD at older ages or after longer delays use different health services than other children with ASD. Results suggest children with diagnostic delays or older diagnosis age were least likely to use conventional ASD therapy and were most likely to use alternate treatments such as medication or CAM. Results also suggest efforts to increase early ASD diagnosis may result in greater ASD-related therapy use and improved functional outcomes for children with ASD.