What this article is about
In brief
This systematic review of 26 studies (2009-2019) found that adults with autism spectrum disorder show increased, not decreased, vulnerability to substance use and substance use disorder, challenging the old assumption that ASD is protective. The pattern was less consistent for adolescents, and routine screening for...
For nursing students
Study summary
For years, autism spectrum disorder (ASD) was assumed to protect people from substance use — the thinking was that social difficulties would keep autistic people away from the peer settings where drinking and drug use usually start. This systematic literature review by Helandri Haasbroek and Neo Morojele, published in the Review Journal of Autism and Developmental Disorders (2022), tested that assumption by pulling together 26 primary studies published between 2009 and 2019 on ASD and substance use in adults and adolescents.
The researchers searched seven databases (SpringerLink, ResearchGate, Cengage Learning, the Journal of Autism and Developmental Disorders, PubMed, Medline, and PsycINFO) using autism and substance-use search terms, screened 671 unique records after removing duplicates, and ended with 26 studies that met their inclusion criteria: primary research in English on adults or adolescents (age 11+) with ASD and either recreational substance use or misuse of prescribed substances.
The overall picture that emerged was more nuanced than a simple yes-or-no answer. Twenty-one of the 26 studies found that people with ASD were more vulnerable to substance use and substance use disorder (SUD) than the general population — not less. But five studies (Hofvander et al. 2009, Ramos et al. 2013, Mangerud et al. 2014, Schapir et al. 2016, and Churchard et al. 2019) found the opposite or no elevated risk. The authors drew particular attention to an age pattern in three of those five: Ramos, Mangerud, and Schapir all studied adolescent or young-adult samples. (The other two were different cases — Hofvander found autistic people no more at risk than other psychiatric patients, and Churchard studied a homeless population.) On this basis the authors concluded that ASD may not be protective for adults, while the picture for younger people is genuinely unclear and possibly different, since adolescents with ASD may be more socially sheltered and have less access to substances through peers.
When substance types were reported, alcohol was the most common substance used, followed by cannabis, with far less use of harder illegal drugs — a pattern the authors linked back to ASD's social-communication difficulties, since obtaining illegal drugs typically requires more complex social networking than buying alcohol or cannabis.
The review also looked at why this vulnerability might exist. Three overlapping explanations came up across the studies: environmental and social factors (loneliness, isolation, and using substances to cope with overstimulation or to feel more able to socialize), executive-functioning deficits (trouble with planning, weighing consequences, and breaking habitual behaviour, which may make it harder to foresee the downsides of substance use), and genetic/neurological overlap (shared genetic risk factors between ASD, ADHD, and SUD, including a possible role for the AUTS2 gene in heroin and alcohol dependence susceptibility). High rates of co-occurring depression, anxiety, and ADHD were repeatedly flagged as compounding the risk.
A recurring and troubling theme was that routine clinical screening for substance use is not standard practice for people with ASD, unlike for other psychiatric conditions such as schizophrenia. Because substance-related symptoms can look similar to autism-related traits (poor self-regulation, executive-function struggles), clinicians may miss SUD in autistic patients entirely. One included study on treatment (using modified cognitive behavioural therapy) showed some real promise, but also revealed that ASD-specific communication needs made standard SUD treatment approaches harder to deliver effectively.
For future nurses, the review is a reminder not to assume a patient's diagnosis rules out other risks. It points to the importance of routinely and non-judgmentally screening ASD patients for substance use, recognizing the specific stressors (isolation, sensory overload, social anxiety) that may drive use in this population, and being aware that standard SUD interventions may need real adaptation to work for autistic clients. The authors are careful to flag that their evidence base is limited — mostly small, cross-sectional studies from wealthy Western countries — so it should inform awareness and further research rather than firm clinical protocols.
Original publication
Source abstract and study details
Read the source abstract
Autism spectrum disorder has often been assumed to be a protective factor against substance use, yet the extent of substance use in this population has been difficult to determine as limited research has been done on these interacting variables. This systematic literature review examined 26 studies published between 2009 and 2019 to uncover the relationship between autism spectrum disorder and substance use. The types of participants included from the primary studies are adults and adolescents. A significant indication that this population is more susceptible to substance use and related disorders was found, yet this may only remain true for adults. Various interacting environmental and genetic/neurological factors combine and may contribute towards this vulnerability such as feelings of isolation, deficits in executive functioning and genetic heritability. High comorbidity rates of depression, anxiety disorders and attention deficit/hyperactivity disorder may further strengthen this vulnerability. Screening for substance use in these patients is not a common practice and the treatment of substance use disorder remains a challenge suggesting that many individuals may remain underdiagnosed. This research paper thus demonstrates the need and importance of more primary research to be done and for greater awareness of this vulnerability within mental health settings.
Reviewed findings
Main findings
- Of the 26 included studies, 21 found that people with ASD have an increased vulnerability to substance use and substance use disorder (SUD) compared with the general population, contradicting the historical assumption that ASD is protective against substance use.
- Five studies found a decreased or no elevated risk of substance use in ASD populations; the authors noted that three of these (Ramos et al. 2013, Mangerud et al. 2014, Schapir et al. 2016) used adolescent or young-adult samples, suggesting the increased-risk finding may hold mainly for adults.
- Among studies that specified substance types, alcohol was the most commonly used substance, followed by cannabis, with lower reported use of illegal 'hard' drugs, which the authors link to the social/communication skills typically needed to obtain illegal substances.
- Vulnerability to substance use in ASD was associated with a combination of environmental/social factors (isolation, coping with social anxiety and overstimulation), neurocognitive factors (executive-functioning deficits affecting risk perception and impulse control), and genetic/neurological overlap with ADHD (including a candidate role for the AUTS2 gene in heroin and alcohol dependence).
- Screening for substance use disorder is not a routine part of clinical assessment for people with ASD (unlike for conditions such as schizophrenia), which the authors argue likely leads to underdiagnosis of SUD in this population.
For teaching and learning
Education implications
- Nurses and clinicians working with autistic adults should not assume that an ASD diagnosis rules out substance use; routine, non-judgmental screening for substance use should be considered as part of standard psychiatric and primary care assessment, similar to practices used for other psychiatric conditions.
- Because comorbid depression, anxiety, and ADHD raise the risk of substance use in people with ASD, clinicians should treat these co-occurring conditions as flags for closer substance-use assessment rather than treating them in isolation.
- Substance intoxication or withdrawal can present with behaviours (poor self-regulation, reduced inhibitory control) that resemble autistic traits, so clinicians should consider substance use as a differential when unexplained behavioural changes appear in ASD patients.
- Standard substance use disorder treatments, including group-based therapy, may need modification for autistic clients — for example, adapting communication style and allowing more session time — since intensive unstructured social interaction can itself be a barrier to engagement.
- Because loneliness, social isolation, and difficulty coping with overstimulation were repeatedly identified as drivers of substance use in ASD, care plans should incorporate social support, structure, and coping-skills components alongside any substance use treatment.
For educators
Teaching and appraisal notes
This appraisal-ready systematic literature review (Haasbroek & Morojele, 2022, Review Journal of Autism and Developmental Disorders 9:1-20) synthesizes 26 primary studies (2009-2019) on the ASD-substance use relationship in adults and adolescents, updating and expanding a 2016 review by Arnevik and Helverschou (18 papers). It is a strong teaching example of PRISMA-guided review methodology paired with a mixed evidence base — useful for practicing critical appraisal rather than accepting a tidy conclusion.
Methodologically, the authors document a full PRISMA flow: 940 records identified across seven databases (search concluded May 2019), 671 remaining after de-duplication, and 26 finally included. Inclusion criteria required English-language primary research (qualitative, quantitative, or mixed methods; including case studies) on participants aged 11+ with ASD, involving recreational substance use or prescribed-substance misuse. Exclusions covered under-11 populations, maternal prenatal substance exposure literature, caregiver substance use, non-substance addictions (gambling, internet), and secondary literature reviews. Instructors can use the published PRISMA diagram and inclusion/exclusion table as a concrete worked example.
Study characteristics are worth flagging for discussion: 20 of 26 studies originated in Europe (predominantly the Netherlands and Sweden), only 6 elsewhere (USA, China, Australia); only 3 were longitudinal; sample sizes ranged from single-digit case studies to a 26,986-participant Swedish national cohort; all studies skewed heavily male; and 11 of 26 studies had overlapping ADHD/ASD samples, complicating attribution of risk to ASD specifically.
The central finding — heterogeneous across the literature — is that 21 of 26 studies found increased SUD/substance-use vulnerability in ASD populations, while 5 (Hofvander et al. 2009; Ramos et al. 2013; Mangerud et al. 2014; Schapir et al. 2016; Churchard et al. 2019) found no elevated or decreased risk. The authors' key interpretive contribution is noting that three of these five discordant studies (Ramos et al. 2013, Mangerud et al. 2014, Schapir et al. 2016) used adolescent or young-adult samples, suggesting the vulnerability effect may be age-dependent (the other two differ: Hofvander found no elevated risk relative to other psychiatric populations, and Churchard studied a homeless sample). This age-dependence hypothesis is the paper's most novel claim and a good discussion point on how reviews generate hypotheses — while modeling caution, since a pattern drawn from three studies is suggestive, not definitive.
Three explanatory mechanisms are proposed and can be mapped directly to nursing curricula on comorbidity and biopsychosocial models: (1) environmental/social factors — isolation, using substances to cope with communication anxiety or sensory overload, or to feel able to socialize; (2) neurocognitive vulnerability — executive-functioning deficits impairing risk assessment and impulse control; and (3) genetic/neurological overlap with ADHD, including candidate-gene work (AUTS2) linking an ASD susceptibility locus to heroin/alcohol dependence. Instructors should note the genetic evidence is thin (essentially one candidate-gene study) and should be presented as hypothesis-generating, not established mechanism.
Clinically, the review's strongest practice-relevant finding is that SUD screening is not routine in ASD care (Palmqvist et al. 2014, Sweden), unlike schizophrenia, creating diagnostic-overshadowing risk since intoxication effects can mimic autistic traits. The Helverschou et al. (2019) case series (n=4) piloting modified CBT for co-occurring ASD/SUD is the only treatment-outcome study in the set and is appropriately underpowered but pedagogically useful for discussing tailored intervention design and small-n exploratory trial limitations.
Suggested classroom uses: (1) PRISMA/appraisal exercise using the published flow diagram and Table 2 summary; (2) discussion of confounding by ADHD comorbidity across 11/26 studies; (3) critique of cross-sectional predominance and its limits for causal direction and age-of-onset inference; (4) discussion of diagnostic overshadowing and screening equity across psychiatric populations; (5) contrast of DSM-IV subtype terminology (Asperger's, PDD-NOS) with DSM-5 unified ASD criteria and the comparability problems this creates across the included literature.
Critical appraisal
Limitations
- Most of the 26 included studies were cross-sectional (only 3 were longitudinal), which prevents the authors from establishing whether ASD causes increased substance use risk or simply co-occurs with it.
- Twenty of the 26 studies originated in European countries and the rest largely from other high-income nations (USA, Australia) with one from China; findings may not generalize to lower-income or non-Western populations with different access to healthcare and different substance use environments.
- Sample sizes varied enormously, from single-digit case studies and small clinical samples (as few as 4-8 participants) to a national cohort of nearly 27,000; several of the more striking findings come from very small samples that the original study authors themselves flagged as preliminary.
Classroom use
Discussion Questions
- Why might ASD have historically been assumed to be protective against substance use, and what does this review suggest is wrong with that assumption for adults specifically?
- The review noted that three of the five studies showing decreased/no increased risk (Ramos, Mangerud, Schapir) were conducted with adolescent or young-adult samples. What competing explanations could account for this age-related pattern besides a true developmental difference in risk?
- How might the predominance of alcohol and cannabis use (versus illegal 'hard' drugs) in ASD populations relate to the social and communication challenges characteristic of autism?
- What ethical and practical challenges arise when trying to introduce routine substance use screening into standard ASD clinical care, and how might nurses working in Canadian mental health and primary-care settings help address them within their scope of practice?
- How could 'diagnostic overshadowing' (where substance-related symptoms are mistaken for autism traits) lead to underdiagnosis of SUD in ASD patients, and what assessment strategies could reduce this risk?
- Given that 11 of the 26 studies included participants with both ASD and ADHD, how confident can we be that the findings reflect ASD-specific risk rather than ADHD or shared risk factors?
Source-based questions
Frequently asked questions
Are adolescents with autism also at higher risk of substance use, according to this review?
The evidence is less clear for adolescents. Among the five studies in this review that did not find an increased risk, three were conducted in adolescent or young-adult samples, which led the authors to suggest the elevated risk found in most studies may be more specific to adults.
Why might people with autism be vulnerable to substance use disorder?
This review identifies three overlapping contributors: social/environmental factors like isolation and coping with anxiety, executive-functioning deficits that impair risk assessment, and genetic/neurological overlap with ADHD and possible shared genetic risk factors.
Can standard substance use disorder treatments work for people with autism?
The review discusses one small study using cognitive behavioural therapy modified for ASD, which showed some success but also highlighted that standard treatment approaches (like group therapy) may need adaptation for autistic clients' communication needs.
Is there a genetic link between autism and substance use disorder?
Preliminary evidence discussed in this review points to shared genetic overlap between ASD and ADHD, and one study identified a candidate gene (AUTS2) associated with both ASD and heroin/alcohol dependence susceptibility, though this evidence is limited and needs further research.
What role does comorbidity with depression, anxiety, or ADHD play in ASD and substance use?
The review notes that high rates of comorbid depression, anxiety disorders, and ADHD may further strengthen the vulnerability of people with ASD to substance use and related disorders.