Comorbidity between Autism Spectrum Disorder and Substance Use Disorders: A Review of Scientific Evidence

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Prevalence and High-Risk Subgroups:

ASD–SUD comorbidity is more frequent than previously assumed. Individuals with ASD and psychiatric comorbidities, particularly ADHD, show increased vulnerability (Butwicka et al., 2017; Huang et al., 2021).

Risk Factors and Explanatory Mechanisms:

Multiple factors contribute to the vulnerability of individuals with ASD to SUDs:

• Self-medication: Many individuals use substances to manage social anxiety, depression, or sensory overload (Arnevik & Helverschou, 2016; Haasbroek & Morojele, 2021).
• Neurobiological deficits: Overlapping reward and motivation systems implicated in ASD and addiction may increase sensitivity to the reinforcing effects of substances (Helverschou et al., 2022).
• Emotional coping difficulties: Problems identifying, expressing, and regulating emotions (alexithymia) can promote substance use as an escape from emotional distress.

Clinical Challenges and Therapeutic Considerations:

ASD–SUD comorbidity presents significant challenges for assessment and treatment:

• Complex clinical evaluation: SUD symptoms may be masked or confused with ASD traits. Repetitive behaviors or intense interests may be misinterpreted as addictive behaviors.
• Individualized treatment: Standard treatments, such as group therapy, may be ineffective for individuals with ASD. Adapted, structured, and predictable interventions focusing on emotional regulation, social skills, and daily routines are recommended (Arnevik & Helverschou, 2016; Helverschou et al., 2022).
• Complex therapeutic needs: Comorbidity requires additional clinical support, including identifying underlying motivations for substance use and personalizing healthy coping strategies.

Integration with Study Objectives:

The findings support the objectives of this review:

1. Evidence on prevalence: ASD–SUD comorbidity is clinically significant, with certain subgroups at higher risk.
2. Risk factors and mechanisms: Multiple vulnerability pathways were identified, including self-medication, neurobiological deficits, and emotional regulation difficulties.
3. Clinical challenges: Diagnostic complexity and the need for individualized approaches were highlighted.
4. Therapeutic implications: Adapted and structured treatments, alongside specialized clinician training, are essential.
5. Knowledge gaps: Longitudinal studies and adapted intervention protocols remain scarce, guiding future research.

Discussion

The findings of this structured narrative review indicate that ASD–SUD comorbidity is more prevalent and clinically significant than previously assumed. Contrary to traditional assumptions that ASD characteristics might protect against substance use, evidence shows that certain subgroups—particularly individuals with ASD without intellectual disability and with psychiatric comorbidities—exhibit heightened vulnerability (Butwicka et al., 2017; Huang et al., 2021).

Explanatory mechanisms include self-medication, neurobiological deficits, alterations in sensory processing, and difficulties with executive function. Self-medication illustrates how substance use can emerge as a coping strategy for social anxiety, depression, or sensory overload (Arnevik & Helverschou, 2016; Haasbroek & Morojele, 2021). Neurobiological overlaps in reward and motivation systems further increase susceptibility (Helverschou et al., 2022). Rothwell (2016) highlights shared molecular and neural pathways, including dopaminergic, glutamatergic, and GABAergic systems, suggesting overlapping mechanisms between ASD and addiction while recognizing distinct clinical trajectories.

Clinical challenges include diagnostic complexity due to overlapping symptoms, underdiagnosis of SUDs in ASD populations, and high dropout rates in conventional treatments (Helverschou et al., 2022; Walhout et al., 2022). These findings underscore the necessity for comprehensive, multidisciplinary evaluations incorporating neurodevelopmental, psychiatric, and addiction knowledge.

Ethical and Social Implications

• Diagnostic approach: Under-identification of SUDs in individuals with ASD raises ethical concerns, as delayed detection can worsen dependency and morbidity. Accurate, unbiased diagnoses are essential to prevent inadequate treatment or discrimination.
• Family context: ASD–SUD comorbidity affects not only the individual but also their families, increasing emotional burden, anxiety, and need for educational and psychological support. Families require information, training, and resources to actively participate in interventions.
• Public health and policy: Evidence highlights the need for early detection programs, adapted interventions, and specialized professional training. This includes clinical protocols for ASD–SUD, prevention programs, and strategies to integrate mental health and addiction services, alongside investment in longitudinal research and community support.

Conclusion

Current evidence indicates that ASD–SUD comorbidity is more frequent than previously assumed, significantly impacting physical, emotional, and social health (Butwicka et al., 2017; Huang et al., 2021). Vulnerability is influenced by self-medication, neurobiological and executive function deficits, difficulties in emotional regulation, and sensory processing challenges (Crane et al., 2013; Gioia et al., 2020; Verdejo-García & Bechara, 2019).

Evaluation and treatment require individualized, structured, and multidisciplinary approaches that integrate ASD characteristics and substance use patterns. The absence of adapted clinical protocols and underdiagnosis of comorbidity reveal important gaps in current practice (William et al., 2025; EMCDDA, 2024).

Mindfulness-based therapies and emotion regulation interventions show promise in adults with ASD and SUDs (Spek et al., 2019), while community-based and systemic programs provide family-inclusive support (Helverschou et al., 2022). Early detection remains critical for better prognosis (Shaw et al., 2022), and policy-level interventions are needed to enhance public health outcomes, including research on prevalence, prevention, and tailored treatment strategies (SAMHSA, 2022, 2024).

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