ANTHROPOLOGICAL RESEARCHES AND STUDIES
No: 16

LONG-TERM ABA THERAPY OUTCOMES FOR CHILDREN WITH AUTISM IN A CLUSTERED SAMPLE FROM ROMANIA

Lăcrămioara PETRE (1), Cristina STAN (2), Aurelia PĂTRAȘCU (3), Monica PETRESCU (4), Suzana TURCU (5)
Keywords: ABA, autism, children, long-term therapy, ABAS-II

DOI: https://doi.org/10.26758/16.1.36

(1), (2), (4), (5) “Francisc I. Rainer” Anthropology Institute of the Romanian Academy, Bucharest, Romania

(3) Peretu Association of Children with Disabilities, Romania

Emails and ORCID iDS:

(1) lacramioara.petre@yahoo.com, https://orcid.org/0009-0008-1571-669X

(2) cristinabest2004@yahoo.com, https://orcid.org/0009-0002-9720-2495

(3) patrascuaurelia76@gmail.com, https://orcid.org/0009-0009-5740-0199

(4) monicapetrescu20032002@yahoo.ca, https://orcid.org/0009-0004-5714-5785

(5) suzana.turcu@antropologia.ro, https://orcid.org/0000-0003-0208-4052

Address correspondence to: Petre Lăcrămioara, “Francisc I. Rainer” Anthropology Institute of the Romanian Academy, email: lacramioara.petre@yahoo.com

Abstract

Objectives: Autism spectrum disorder (ASD) is a neurodevelopmental condition characterized by challenges in social communication and restricted, repetitive behaviors. Although no cure exists, various therapeutic approaches—especially early intervention programs—have shown positive effects on cognitive, social, and adaptive functioning. Applied Behavior Analysis (ABA) is one of the most empirically supported interventions for ASD and the most widely used in Romania.

Methods: This study evaluated the long-term outcomes of ABA therapy in a clustered sample of 23 children (19 boys, 4 girls) aged 4–11, all independently diagnosed with ASD. The children received consistent ABA therapy in the same Romanian therapy center for 4 years. Progress was measured annually using the Adaptive Behavior Assessment System–Second Edition (ABAS–II), assessing Conceptual, Social, and Practical adaptive behavior domains.

Results: At baseline, mean composite scores were low across domains: Conceptual (68.74), Social (64.96), Practical (64.39), and General Adaptive Composite (GAC: 63.57). After 4 years, mean improvements were: Conceptual (+17.30), Social (+16.70), Practical (+21.26), and GAC (+21.65). However, individual trajectories varied significantly, with some children showing regression—especially in the Social domain (range: -31 to +67, SD = 23.57).

Conclusions: While group-level progress after long-term ABA therapy is evident, individual outcomes are inconsistent. These findings underscore the need for individualized treatment planning and further research into factors influencing therapeutic response.

Keywords: ABA, autism, children, long-term therapy, ABAS-II

Suggested citation (APA):

Petre, L., Stan, C., Pătrașcu, A., Petrescu, M., & Turcu, S. (2026).  Long-term ABA therapy outcomes for children with autism in a clustered sample from Romania. Anthropological Researches and Studies, 16, 569-583. https://doi.org/10.26758/16.1.36

Introduction

Autism spectrum disorder (ASD) is a complex neurodevelopmental condition characterized by persistent difficulties in social communication and interaction, accompanied by restricted and repetitive patterns of behavior, interests, or activities. Symptoms typically emerge in early childhood and vary considerably in severity and manifestation, which underlies the use of the term spectrum (American Psychiatric Association, 2013).

Recent surveillance data from the U.S. Centers for Disease Control and Prevention estimate the prevalence of ASD at approximately 1 in 31 children, with boys affected 3.4 times more frequently than girls (Shaw et al., 2025). European data, while heterogeneous due to differences in diagnostic criteria and reporting systems, reveal a comparable upward trend in ASD identification. In Romania, official epidemiological statistics remain limited; however, reports from specialized centers and academic studies indicate a continuous increase in diagnoses, largely attributed to heightened awareness and improved access to services (Pasco et al, 2014)

ASD is a lifelong condition that influences multiple domains of functioning, including language acquisition, adaptive behavior, executive processes, and sensory integration. Although no curative treatment currently exists, early and sustained evidence-based interventions, particularly behavioral and developmental approaches, have been shown to significantly enhance quality of life and foster greater functional independence among autistic children (Lord et al., 2018).

Given the diverse manifestations of autism spectrum disorder (ASD), individualized and intensive intervention programs are widely recognized as best practice. Among these, Applied Behavior Analysis (ABA) stands out as the most implemented therapeutic approach for children with ASD in Romania. Grounded in behavioral science, ABA employs structured, evidence-based techniques to enhance developmental domains such as communication, social interaction, adaptive behavior, and cognitive functioning.

In Romania, the delivery of ABA therapy is predominantly facilitated by non-governmental organizations (NGOs) and licensed psychologists operating in private practices or specialized centers. This reliance on non-public providers stems from the limited integration of ABA services within the national healthcare system, compelling families to seek support through NGO-led initiatives or private professionals (Raiu, 2021).

Early intervention plays a pivotal role in shaping developmental outcomes for children with ASD. The period before age five is characterized by heightened neuroplasticity and rapid brain development, making it an optimal window for therapeutic engagement. Longitudinal research has consistently demonstrated that timely, personalized interventions during this stage yield significant improvements in language development, cognitive functioning, adaptive behavior, and behavioral regulation, while also reducing symptom severity. These benefits extend beyond childhood, contributing to increased autonomy and quality of life in later stages of development (Dawson et al., 2010; Estes et al., 2015).

ABA therapy, specifically, is rooted in the principles of operant conditioning and focuses on the systematic modification of socially significant behaviors. Its methodology emphasizes clearly defined goals, continuous data collection, positive reinforcement, and individualized treatment plans tailored to each child’s unique profile. Numerous studies have validated ABA’s effectiveness in enhancing communication, social skills, academic performance, and daily living abilities (Eckes et al., 2023). Intensive programs—typically involving 20 to 40 hours of therapy per week—have been shown to produce substantial developmental gains, particularly when initiated early and maintained consistently over time (Eldevik et al., 2009; Reichow et al., 2018).

Despite the widespread recognition of Applied Behavior Analysis (ABA) as an evidence-based intervention for autism, most empirical research has been conducted in North American and Western European contexts. This geographic concentration limits the generalizability of findings to other cultural and systemic environments. In countries like Romania, where access to diagnostic and therapeutic services remains uneven and is often concentrated in urban centers, it is essential to investigate how ABA performs within these distinct settings.

The present study seeks to evaluate the long-term outcomes of ABA therapy in a clustered sample of Romanian children diagnosed with ASD who received continuous intervention over a four-year period. Utilizing the Adaptive Behavior Assessment System, Second Edition (ABAS–II) as a standardized measurement tool, the research aims to assess changes in conceptual, social, and practical adaptive functioning—both at the group level and across individual developmental trajectories (Gray & Carter, 2013).

This study contributes to the limited body of empirical literature on ABA outcomes in Eastern Europe. By documenting the variability in therapeutic progress among children with ASD, it underscores the importance of individualized treatment planning and ongoing performance monitoring. The findings have the potential to inform clinical practice, shape policy development, and support the expansion of effective autism services in Romania and comparable contexts.

Literature Review: Long-Term Outcomes of ABA

While the short-term benefits of Applied Behavior Analysis (ABA) are well-established, research examining its long-term effects—spanning multiple years of intervention—is comparatively limited but gaining increased attention. For instance, Smith et al. (2000) conducted a four-year longitudinal study demonstrating sustained improvements in IQ, academic performance, and adaptive behavior. Similarly, Eldevik et al. (2010) reported significant developmental gains over a three-year period, although individual progress varied considerably.

To evaluate such outcomes, standardized instruments like the Adaptive Behavior Assessment System (ABAS–II) and the Vineland Adaptive Behavior Scales (VABS) are frequently employed. These tools assess adaptive functioning, which is a critical indicator of real-world independence and quality of life—dimensions not adequately captured by IQ tests alone (Kanne et al., 2011). Improvements in adaptive behavior are strongly correlated with long-term prognosis and successful integration into mainstream educational environments.

Over the past decade, the scientific community has increasingly focused on the sustainability and variability of progress resulting from long-term behavioral interventions, particularly ABA. While early intervention remains foundational in autism treatment, understanding how gains persist or evolve over time is essential. ABA continues to be recognized as one of the most effective and empirically supported approaches, especially when delivered intensively and tailored to the child’s unique developmental profile (Zwaigenbaum et al., 2015).

Several longitudinal studies have explored these dynamics. Eldevik et al. (2012), in one of the most cited European studies, found that children receiving 20–30 hours of ABA therapy per week over three years exhibited substantial improvements in both cognitive and adaptive domains, particularly in communication and daily living skills—key predictors of functional independence. Likewise, Granpeesheh et al. (2014) analyzed data from over 150 children in intensive ABA programs and concluded that early responsiveness within the first 6–12 months was a strong predictor of sustained progress. This finding is echoed in more recent reviews (Tiura et al., 2017; Paynter et al., 2020), which emphasize the importance of individualized monitoring and early indicators of treatment efficacy.

A central consideration in evaluating long-term ABA outcomes is the selection of appropriate measurement tools. While IQ and language assessments provide useful benchmarks, they often fail to capture functional competencies such as dressing independently, navigating social interactions, or following classroom routines. Instruments like the VABS and ABAS-II/ABAS-3 offer a more ecologically valid assessment of practical, conceptual, and social functioning over time. For example, Vismara and Rogers (2021) found that gains in adaptive functioning were not only measurable but often more clinically meaningful than changes in IQ, particularly among children with moderate to severe autism. More recently, McCormick et al. (2023) highlighted that adaptive skills are more closely linked to long-term outcomes such as educational placement, peer relationships, and family independence than cognitive scores alone. Their findings also underscore the variability in individual trajectories—some children show steady progress, while others plateau or regress in specific domains. This heterogeneity reinforces the need for personalized treatment plans and continuous assessment throughout therapy.

Meta-analyses over the past decade support these conclusions while also identifying persistent limitations in the literature. Reichow and Wolery (2009) called for more rigorous research designs, a need that has been partially addressed. However, challenges such as small sample sizes, inconsistent implementation fidelity, and limited cultural diversity remain. More recent reviews, including Sandbank et al. (2020), stress the importance of distinguishing between efficacy (results in controlled settings) and effectiveness (outcomes in real-world contexts). Their work highlights the necessity of conducting studies in non-Western countries, where systemic, economic, and cultural factors may significantly influence therapy delivery and outcomes.

In this regard, research from Eastern Europe remains sparse. Although ABA has gained traction in Romania over the past 15 years, peer-reviewed data on long-term outcomes are still limited. Local variables—such as therapist availability, parental involvement, delayed diagnoses, and lack of public funding—can substantially affect the success of interventions. For instance, Nicolae et al. (2020) surveyed Romanian families and clinicians and found considerable discrepancies in ABA implementation, with many children receiving fewer than the recommended therapy hours due to financial constraints or therapist shortages. These findings underscore the urgent need for context-sensitive research that reflects the lived experiences and developmental trajectories of autistic children in Romania and similar regions.

Taken together, the evidence suggests that long-term ABA interventions can yield durable and meaningful improvements in adaptive functioning, particularly when interventions are individualized and closely monitored. Nonetheless, variability in outcomes remains a central theme. Tools like the ABAS-II provide a robust framework for capturing these nuanced patterns of change. As autism services continue to evolve globally, there is a pressing need for research that combines methodological rigor with cultural relevance. The present study contributes to this effort by offering one of the few longitudinal assessments of ABA therapy in Romania, using standardized adaptive behavior data to explore both group-level trends and individual variability over a four-year period.

Variability in Response to ABA Therapy

Although ABA is widely recognized for its effectiveness in treating autism spectrum disorder (ASD), research consistently underscores the heterogeneity in individual treatment responses. While some children exhibit rapid and substantial developmental gains, others progress more slowly or show minimal improvement—even when exposed to interventions of similar intensity and duration. This variability is influenced by several factors, including baseline cognitive functioning, co-occurring conditions (e.g., intellectual disability, ADHD, anxiety), initial language abilities, and the degree of family involvement (Rogers & Vismara, 2008; Vivanti et al., 2014).

The concept of differential responsiveness to ABA was notably introduced by Sherer and Schreibman (2005), who categorized children as “responders” or “non-responders” based on their developmental trajectories. Subsequent studies have reinforced this framework, suggesting that early progress—particularly within the first 6 to 12 months of therapy—may serve as a reliable predictor of long-term outcomes (Fein et al., 2013). These findings highlight the importance of individualized progress monitoring and caution against assuming uniform effectiveness across all children within group-based interventions.

ABA in the Romanian and Eastern European Context

Over the past two decades, autism intervention in Romania has undergone notable development, largely driven by non-governmental organizations (NGOs), private psychology practices, and grassroots advocacy. Despite ongoing challenges in integrating autism services into the public healthcare system, a range of therapeutic models is now available, with Applied Behavior Analysis (ABA) remaining the most prominent. Other commonly used approaches include speech and language therapy, occupational therapy, and, more recently, animal-assisted and integrative therapies. A key determinant of positive developmental outcomes in children with autism spectrum disorder (ASD) is the timing of intervention. Early childhood, particularly before age five, is characterized by heightened neuroplasticity and responsiveness to structured learning environments. Romanian research supports the global consensus that early diagnosis followed by targeted therapy significantly enhances outcomes in language, adaptive behavior, and emotional regulation (Bajko & Bazgan, 2018). Their study, based on clinical cases from Brașov, emphasizes that delays in diagnosis are often associated with persistent deficits in communication and socialization.

In practice, early intervention programs in Romania are primarily delivered through NGO-led centers, especially in urban areas such as Bucharest, Cluj, and Iași. These centers typically employ a multidisciplinary model that integrates ABA, developmental psychology, speech-language therapy, and parental coaching. In a qualitative study, Grasu (2015) identified team coordination, individualized treatment plans, and active parental involvement as key components of effective practice. However, systemic barriers remain, including the lack of formal accreditation for ABA therapists, inconsistent funding, and the absence of centralized guidelines.

Complementary therapies are also gaining visibility. For example, Zagrai et al. (2024) demonstrated that canine-assisted therapy can enhance social engagement and emotional responsiveness in children with ASD. In a pilot study conducted in Bistrița, participants in dog-assisted sessions showed significant improvements in eye contact, group play, and task participation, with effect sizes ranging from 15% to 38% compared to control groups. While not a replacement for core interventions like ABA, such methods may offer valuable support in socio-emotional development.

School inclusion is another major focus of Romanian therapeutic strategies. According to Ivan, Ciolcă, and Dreve (2021), pre-integration programs are essential for preparing children with ASD to transition into mainstream educational settings. These programs often combine behavioral therapy, occupational training, and classroom adaptations to address challenges in attention, motor coordination, and sensory processing. The authors stress the importance of individualized educational planning (IEP) and ongoing teacher training as prerequisites for sustainable inclusion. Despite these advancements, autism therapy has yet to be institutionalized as a standardized medical service within Romania’s public healthcare system. Consequently, most families rely on private funding or NGO support, leading to disparities in access between urban and rural populations. Nevertheless, the increasing number of ABA-certified professionals, growing international collaborations, and heightened awareness among educators and healthcare providers signal promising steps toward broader systemic integration.

Objectives

The present study aims to investigate the long-term effects of Applied Behavior Analysis (ABA) therapy on children diagnosed with autism spectrum disorder (ASD) in a Romanian clinical context. Specifically, it examines the developmental trajectories of a cohort of children who received ABA-based intervention over a four-year period in a consistent therapeutic environment. The study focuses on quantifying changes in adaptive functioning across multiple domains—Conceptual, Social, and Practical—using standardized assessment tools.

The primary objectives of this study are:

  1. To assess group-level progress in adaptive behavior (Conceptual, Social, Practical, and General Adaptive Composite domains) in children with ASD after four years of continuous ABA therapy.
  2. To evaluate the variability of individual developmental outcomes within the sample, identifying patterns of improvement, plateau, or regression in adaptive functioning.
  3. To explore the distribution of progress across specific adaptive behavior domains and determine which areas are most responsive or resistant to intervention.
  4. To contribute empirical data to the limited body of research on long-term ABA therapy outcomes in Eastern Europe, particularly Romania, where systemic, cultural, and structural variables may influence treatment effectiveness.
  5. To highlight the importance of individualized progress monitoring in autism therapy and advocate for further research on predictive factors influencing long-term treatment response.

Material and Methods

Participants. The study included a sample of 23 children (19 boys and 4 girls) diagnosed with autism spectrum disorder (ASD). The participants were aged between 4 and 11 years at the beginning of the intervention. All children had been independently diagnosed by licensed clinicians according to the DSM-5 criteria, using standardized diagnostic tools. The inclusion criteria required that all participants: (1) had received a formal ASD diagnosis, (2) were enrolled in a full-time ABA program at the same therapy center in Romania, and (3) had undergone continuous ABA therapy for at least four years. No participants were excluded based on the severity of their condition.

Setting. All participants received therapy at a private ABA center located in an urban area in Romania. The center operates with a team of trained therapists under the supervision of Board Certified Behavior Analysts (BCBAs). Therapy was delivered in a one-on-one format and took place in structured therapy rooms designed to minimize distractions and facilitate individualized instruction. All sessions followed structured behavioral protocols tailored to the developmental needs and learning profiles of each child.

Measures. To assess the children’s development over time, the Adaptive Behavior Assessment System–Second Edition (ABAS-II) was used as the primary measurement tool. The ABAS-II is a standardized, norm-referenced assessment that evaluates adaptive functioning across three main domains:

Conceptual (e.g., communication, functional academics, self-direction),

Social (e.g., leisure, social skills),

Practical (e.g., self-care, home living, safety).

These domain scores are combined into a General Adaptive Composite (GAC) score, which provides an overall estimate of the child’s adaptive functioning. Procedure

At the beginning of the study, baseline assessments were conducted using the ABAS-II. The same assessment was repeated annually for four consecutive years to monitor progress. During the intervention period, each child received intensive ABA therapy for approximately 15-20 hours per week. Therapy goals were individualized and included programs targeting communication, self-help skills, play, academic readiness, and social interaction. Progress was tracked monthly using behavior analytic data collection systems, and treatment plans were updated quarterly based on performance. All therapists involved in the study had formal training in ABA principles and techniques, and sessions were supervised regularly to ensure fidelity to intervention protocols.

Results

The longitudinal analysis of adaptive behavior outcomes was conducted using scores from the ABAS-II administered annually over a four-year period. The results are presented across the four composite domains: Conceptual, Social, Practical, and General Adaptive Composite (GAC) in Table 1.

Table 1

 The means of the composite scores at baseline and over the 4 years of research (5 measurements) (to see Table 1, please click here)

From baseline to the 4-year follow-up, the GAC increased by 21.65 points (from 63.57 to 85.22), with the standard deviation increasing from 18.00 to 25.16, indicating greater variability in outcomes over time. The largest improvements were observed in the GAC and Practical domains, with gains of 21.65 and 21.26 points respectively. Conceptual and Social domains improved by 17.30 and 16.70 points.

Effect sizes calculated using Cohen’s d (mean difference divided by pooled standard deviation) for baseline to 4 years were:

GAC: d≈0.91 (large effect)

Conceptual: d≈0.76 (moderate to large effect)

Social: d≈0.70 (moderate effect)

Practical: d≈0.88 (large effect)

Year-to-year increments were relatively consistent, with the greatest annual gains in GAC and Practical domains occurring during the first two years. The Social domain showed slower but steady improvement, with the smallest gain after year 1 but larger increases after year 3. The Conceptual domain plateaued somewhat after year 2, suggesting early rapid development followed by stabilization.

These results align with prior research indicating that intensive, sustained intervention yields meaningful adaptive skill gains, particularly in practical and general functioning domains, with somewhat more gradual improvements in social skills. The increasing standard deviations over time may reflect individual variability in response to intervention.

Figure 1 shows the mean year-to-year changes in composite scores across the General Adaptive Composite (GAC) and its Conceptual, Social, and Practical domains, highlighting the dynamic progression of skills throughout the four-year intervention. The data show that while all domains benefit from sustained intervention, the timing and magnitude of improvements vary by domain. Cognitive (Conceptual) and general adaptive (GAC) skills show rapid early gains with later plateaus or slower growth, whereas social skills exhibit a delayed but more pronounced improvement pattern beginning in Year 2. Practical skills increase steadily with no clear plateau over the four years. These patterns align with the understanding that social skills may require extended intervention duration to develop fully, while cognitive and practical skills may respond more immediately to early intervention.

Figure 1

The means of the annual progress of composite scores for the entire group (to see Figure 1, please click here)

Despite the overall upward trend, a closer examination of individual data revealed a high degree of variability in developmental trajectories. While most participants demonstrated consistent progress across domains, a minority showed limited gains or even regression in certain areas.

In the Social domain, individual progress scores ranged from -31 to +67, with a standard deviation of 23.57, highlighting a wide dispersion of outcomes. Several children demonstrated exceptional improvements, whereas others experienced stagnation or a decline in specific subskills, despite continued intervention (Figure 2).

Figure 2

Individual Social scores after 4 years of ABA therapy (n=23) (to see Figure 2, please click here)

The longitudinal data for the Social domain in four selected participants (Subjects 5, 10, 19, and 20) over the 4-year intervention period reveal notable inter-individual variability in response to therapy. (Figure 3)

Figure 3

The longitudinal data for the Social domain in four selected participants (Subjects 5, 10, 19, and 20) (to see Figure 3, please click here)

The developmental trajectories of the four selected participants illustrate the variability in response to ABA therapy, particularly in the social domain. Subject 5 showed a pattern of initial decline, partial recovery, and eventual regression, indicating limited long-term benefit and possible stagnation. Subject 10 demonstrated early gains followed by a sharp drop and partial recovery, suggesting sensitivity to external factors or inconsistency in intervention. Subject 19 exhibited a persistent downward trend with minimal recovery, reflecting poor responsiveness to therapy. In contrast, Subject 20 displayed a delayed but sustained improvement, highlighting the potential for significant progress even after an initial decline. These patterns emphasize the need for individualized monitoring and flexible intervention strategies to accommodate diverse developmental responses.

A similar pattern of variability was noted in other domains, although to a lesser extent. For instance: Conceptual scores showed individual changes ranging from approximately -10 to +45, Practical domain changes ranged from -5 to +60, GAC scores had a range from -4 to +65. This heterogeneity underscores the individualized nature of treatment response and suggests that group-level averages may obscure significant intra-sample differences. For example, Subject 5 shows very different trajectories for all four domains (Figure 4).

Overall, the longitudinal trajectory of Subject 5 suggests an initial period of relative stability, followed by a transient domain-specific improvement in conceptual skills during the second year, and subsequently, a generalized decline across all domains by year four. This pattern may indicate insufficient long-term therapy effectiveness for this participant, potential regression due to external factors, or challenges in skill generalization and retention. The variability across domains also supports the necessity of individualized and dynamic intervention strategies.

Figure 4

Subject’s 5 longitudinal trajectories for all 4 domains for 4 years therapy (to see Figure 4, please click here)

Discussion

This study aimed to evaluate the long-term outcomes of Applied Behavior Analysis (ABA) therapy in a cohort of Romanian children diagnosed with autism spectrum disorder (ASD) over a four-year intervention period. The findings demonstrate statistically and clinically significant improvements in adaptive functioning at the group level, particularly in the Practical and General Adaptive Composite (GAC) domains. These results are consistent with prior research indicating that sustained ABA-based interventions can yield substantial developmental gains when delivered consistently over extended periods (Anderson & Carr, 2021).

Improvements in the Conceptual and Social domains, while positive on average, exhibited greater individual variability. This aligns with existing literature emphasizing that treatment response is not uniform and may be influenced by factors such as baseline cognitive functioning, language abilities, comorbid conditions, and family involvement (Paynter et al., 2020; Tiura et al., 2017). The high standard deviation observed in the Social domain, along with instances of regression, underscores the need for individualized treatment approaches and ongoing monitoring of social skill development.

The study further confirms that long-term engagement in therapy is essential but does not guarantee uniform progress. Some participants demonstrated slower or regressive patterns despite consistent exposure to the same therapeutic setting and team. These findings support calls to move beyond group averages and investigate predictors of treatment responsiveness (McCormick et al., 2023; Sandbank et al., 2020). Additionally, structural differences in ABA implementation in Romania—such as variability in therapist training, service accessibility, and systemic support—may influence intervention fidelity and outcomes (Nicolae et al., 2020). Recent perspectives also highlight the importance of aligning early interventions with neurodiversity principles and autistic values. This reinforces the need for ABA programs that are not only effective but also individualized, respectful, and affirming (Sulek et al., 2025).

In summary, while ABA remains a robust and empirically supported intervention for many children with ASD, its outcomes are heterogeneous. The study emphasizes the importance of standardized assessments (e.g., ABAS-II) to guide therapy adjustments and advocates for research that considers long-term, real-world functioning—particularly in underrepresented regions such as Eastern Europe.

Limitations

Several limitations should be acknowledged. First, the study utilized a relatively small, non-random sample from a single therapy center, which limits the generalizability of the findings. Second, the absence of a control or comparison group precludes definitive causal conclusions regarding ABA effectiveness. Third, reliance on ABAS-II composite scores, while informative, may not capture the full spectrum of functional changes or contextual factors influencing development. Future studies may benefit from incorporating mixed-method designs to address these limitations and provide a more nuanced understanding of therapy outcomes.

Future Directions

Future research should aim to identify predictors of individual progress and treatment responsiveness, including language level at intake, family involvement, and comorbid conditions. Larger-scale, multi-center studies across Romania and other Eastern European countries are needed to explore systemic influences and inform public policy and funding strategies for ASD interventions. Additionally, longitudinal follow-up beyond four years would help assess the sustainability of gains into adolescence. Mixed-method approaches that integrate quantitative assessments with qualitative insights from families and therapists could further enrich understanding of therapy dynamics and lived experiences.

Conclusions

This study investigated the long-term effects of Applied Behavior Analysis (ABA) therapy on adaptive functioning in a group of Romanian children diagnosed with autism spectrum disorder (ASD) who received consistent intervention over a four-year period. Using the ABAS-II as the primary assessment tool, the study tracked individual and group-level progress across the domains of Conceptual, Social, Practical functioning, and the General Adaptive Composite (GAC).

The results reveal significant improvements in all measured domains, with the most pronounced gains observed in Practical skills and overall adaptive functioning. These findings support a growing body of evidence that sustained, structured ABA intervention contributes meaningfully to the development of essential life skills in children with ASD. However, the data also highlight considerable variability in individual outcomes, particularly in the Social domain, where progress ranged from substantial gains to stagnation or regression.

These findings underscore the effectiveness of long-term ABA interventions while emphasizing the necessity of individualized treatment planning and continuous progress monitoring. Clinicians must remain responsive to each child’s unique developmental profile, adjusting goals and strategies accordingly. Strictly standardized programs may limit therapeutic effectiveness, especially in complex domains such as social communication.

This study also contributes to the limited body of Eastern European research on autism treatment outcomes. Romania’s evolving therapeutic landscape offers a valuable context for further inquiry into how structural, cultural, and systemic factors influence the delivery and impact of evidence-based interventions.

Future research should explore predictors of individual responsiveness to ABA therapy, including language development, cognitive level, comorbidities, family involvement, and therapist expertise. Longitudinal studies with larger, more diverse samples are needed to validate these findings and assess generalizability. Moreover, incorporating mixed-method approaches—combining quantitative assessments with qualitative data—may yield deeper insights into treatment dynamics, barriers, and the generalization of acquired skills to naturalistic settings.

In conclusion, this study confirms that long-term ABA intervention can lead to meaningful gains in adaptive behavior among children with autism in Romania. It also illustrates the heterogeneity of individual outcomes, reinforcing the need for flexible intervention models, continuous assessment, and a deeper understanding of contextual influences to optimize therapeutic impact and support each child’s developmental potential.

Competing interests

The authors declare no competing interests.

Ethics Committee Approval

This study was reviewed and approved by the Ethics Committee of the “Francisc I. Rainer” Institute of Anthropology, Romanian Academy. All study procedures were conducted in accordance with the ethical standards of the institutional research committee and with the principles of the Declaration of Helsinki and its subsequent amendments.

Consent to participate

Written informed consent was obtained from the parent or legal guardian of each participating child prior to enrollment in the study. The consent included permission for the collection, analysis, and anonymous use of the data for scientific research and publication purposes. Participants’ confidentiality and privacy were protected throughout the study.

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