AuDHD & stimulant medication

In this article, we explore what the research says about stimulant medication for AuDHDers.

What are stimulants?

Stimulants are a class of medication that include drugs such as methylphenidates (e.g., Concerta or Ritalin), amphetamines (e.g., Adderall), lisdexamfetamine (e.g., Vyvanse), etc. They generally work by increasing two chemicals in our brain that are known to influence executive functioning: dopamine and norepinephrine. They are considered the most effective way to support ADHDers with their executive functioning challenges.

An ADHD vs. AuDHD example

Many (but not all) people with ADHD report that stimulant medication completely changed their lives. For example, a friend of mine described the experience of taking stimulants as having an immediate and palpable effect. They said within 1 hour of taking it for the first time, they felt a complete switch. Until that day, they did not know what it felt like to “have a quiet mind” or to “want to do something and just be able to decide to do it”. They say that the medication has helped them at work, at home, and even with managing their relationships.

I am AuDHD (autistic + ADHD), and I have taken stimulant medication to try and help with some of my disabling ADHD traits, such as my poor task initiation. However, I did not have a similar seemingly magical experience. It helped with my concentration a little bit, but it also heightened many of my disabling autistic traits like my sensory sensitivity, my low tolerance for ambiguity, and my struggles with task switching. I also experienced a lot of side effects and ultimately discontinued the medication after trying several kinds.

Looking into the research, it seems that our drastically different experiences are not uncommon. In general, stimulants do not seem to work the same way for AuDHD individuals and ADHD individuals.

Stimulant use in AuDHD

Considering that 50–70% of autistics also have ADHD^[1]The comorbidity of ADHD in children diagnosed with autism spectrum disorder (Stevens, et al. 2016)^[2]Identifying comorbid ADHD in autism: Attending to the inattentive presentation (Rau et al., 2020)^[3]Prevalence of attention-deficit/hyperactivity disorder in individuals with autism spectrum disorder: A meta-analysis (Rong et al., 2021), stimulants are a popular medication of choice for AuDHDers. Up to 52% of autistics are prescribed stimulants, especially in childhood.^[4]Use of psychotropic drugs in patients with autism spectrum disorders: a systematic review (Jobski et al., 2016)^[5]Understanding the Diversity of Pharmacotherapeutic Management of ADHD With Co-occurring Autism: An Australian Cross-Sectional Survey (Mellahn et al., 2022) However, just because they are commonly prescribed doesn’t necessarily mean that they are actually helpful for AuDHDers.

Are stimulants helpful for AuDHD?

Quite a few studies show that stimulants are effective in managing the challenging aspects of ADHD for those who are also autistic (AuDHD).^[6]Dose-Response Effects of Long-Acting Liquid Methylphenidate in Children with Attention Deficit/Hyperactivity Disorder (ADHD) and Autism Spectrum Disorder (ASD): A Pilot Study (Ghanizadeh et al., 2017)^[7]Methylphenidate in Autism Spectrum Disorder: A Long-Term Follow Up Naturalistic Study (Ventura et al., 2020)^[8]Effects of Extended-Release Methylphenidate Treatment on Cognitive Task Performance in Children with Autism Spectrum Disorder and Attention-Deficit/Hyperactivity Disorder (Pearson et al., 2020)^[9]The effect of autistic traits on response to and side-effects of pharmacological ADHD treatment in children with ADHD: results from a prospective clinical cohort (Lilja et al., 2022) However, when looking at the field of research as a whole, these positive effects do not appear to be reliable.

Overall, stimulants are not as effective for AuDHDers compared to ADHDers.^[10]The pediatric psychopharmacology of autism spectrum disorder: A systematic review – Part I: The past and the present (Persico et al., 2021)^[11]Pharmacotherapy in autism spectrum disorders, including promising older drugs warranting trials (Hellings, 2023)^[12] Pharmacotherapy of Attention-Deficit/Hyperactivity Disorder in Individuals with Autism Spectrum Disorder (Joshi & Wilens, 2022)^[13]An Update on Psychopharmacological Treatment of Autism Spectrum Disorder (Aishworiya et al., 2022) Data find that 75% of ADHDers respond positively to stimulants but only 49% of AuDHDers do.^[14]Pharmacotherapy in autism spectrum disorders, including promising older drugs warranting trials (Hellings, 2023) Moreover, of the AuDHDers that find stimulants to be helpful, they are not as helpful as they are for ADHDers.^[15]Pharmacotherapy in autism spectrum disorders, including promising older drugs warranting trials (Hellings, 2023)

This pattern of findings is consistent across measures of several different ADHD traits. In AuDHD, studies find that stimulants are either less helpful or not helpful at all for reducing hyperactivity,^[16]Pharmacotherapy of attention deficit/hyperactivity disorder in individuals with autism spectrum disorder: A systematic review of the literature (Joshi et al., 2020)^[17]The pediatric psychopharmacology of autism spectrum disorder: A systematic review – Part I: The past and the present (Persico et al., 2021)^[18]Effects associated with on- and off-label stimulant treatment of core autism and ADHD symptoms exhibited by children with autism spectrum disorder (Barnard-Brak et al., 2019) inattention,^[19]The pediatric psychopharmacology of autism spectrum disorder: A systematic review – Part I: The past and the present (Persico et al., 2021)^[20]Effects associated with on- and off-label stimulant treatment of core autism and ADHD symptoms exhibited by children with autism spectrum disorder (Barnard-Brak et al., 2019) and impulsivity.^[21]The pediatric psychopharmacology of autism spectrum disorder: A systematic review – Part I: The past and the present (Persico et al., 2021)^[22]Effects associated with on- and off-label stimulant treatment of core autism and ADHD symptoms exhibited by children with autism spectrum disorder (Barnard-Brak et al., 2019)

One study did find that stimulant medication helped AuDHD individuals process information more quickly. But, there were no actual effects on improving attention, arguably one of the most challenging parts of having ADHD for managing day-to-day.^[23]Processing speed as a marker to stimulant effect in clinical sample of children with high functioning autism spectrum disorder (Peled et al., 2019)

Other studies suggest that these findings depend on individual IQ. In AuDHD, stimulants seem to be more effective for individuals with higher IQs compared to lower IQs.^[24]Pharmacotherapy of attention deficit/hyperactivity disorder in individuals with autism spectrum disorder: A systematic review of the literature (Joshi et al., 2020) Stimulants also seem to be more effective for AuDHDers who have low support needs compared to high support needs.^[25]Pharmacotherapy in autism spectrum disorders, including promising older drugs warranting trials (Hellings, 2023) Finally, stimulants seem to be most effective for AuDHDers who have more prominent ADHD traits compared to autistic traits. For example, in AuDHD individuals who have a lower preference for routine and repetitive behaviours.^[26]Pharmacotherapy in autism spectrum disorders, including promising older drugs warranting trials (Hellings, 2023)

Are there negative effects?

Stimulants seem to be less tolerable for AuDHDers compared to ADHDers.^[27]Practitioner Review: Pharmacological treatment of attention-deficit/hyperactivity disorder symptoms in children and youth with autism spectrum disorder: a systematic review and meta-analysis (Rodrigues et al., 2020) One report found that side effects in AuDHDers were double those of ADHDers. In this study, 18% of participants discontinued the medication due to side effects related to irritability, decreased appetite, and insomnia.^[28]Pharmacotherapy in autism spectrum disorders, including promising older drugs warranting trials (Hellings, 2023)

One commonly cited distressing side effect of stimulant use in AuDHD is emotion dysregulation or negative mood-related experiences.^[29]Pharmacotherapy of attention-deficit/hyperactivity disorder in individuals with autism spectrum disorder: A systematic review of the literature (Joshi et al., 2020) But once again, this finding doesn’t seem to be reliable. Other studies find that there is no real difference in measures of emotion dysregulation, like irritability, in AuDHDers who take stimulants.^[30]The effect of stimulants on irritability in autism comorbid with ADHD: a systematic review (Ghanizadeh et al., 2019)

I personally also experienced an unwanted heightening of many of my autistic traits. My sensory sensitivities were a lot more intense and my ability to switch tasks was a lot lower. I guess it helped my concentration because I was basically in hyperfocus all day every day, but this came at the expense of being able to take care of myself like eat, shower, and sleep. Instead, I would work on the same task for hours and not be able to shift away unless some sensory change in my environment caused me to immediately experience a meltdown.

Research limitations

Many of the inconsistencies found in the research may be explained by how the studies tend to be conducted.^[31]The effect of stimulants on irritability in autism comorbid with ADHD: a systematic review (Ghanizadeh et al., 2019)^[32]Practitioner Review: Pharmacological treatment of attention-deficit/hyperactivity disorder symptoms in children and youth with autism spectrum disorder: a systematic review and meta-analysis (Rodrigues et al., 2020) One study notes that the majority of the studies that find positive effects for stimulant use in AuDHD are only conducted for a short period of time (typically 1 to 2 weeks) and so the efficacy of these positive effects may not outweigh the negative effects in the long-run.^[33]Practitioner Review: Pharmacological treatment of attention-deficit/hyperactivity disorder symptoms in children and youth with autism spectrum disorder: a systematic review and meta-analysis (Rodrigues et al., 2020)

Most studies are also conducted in children. This means that the results are usually determined based on parent and teacher reports. Therefore, the positive effects in certain studies may be based on external outsider observations instead of internal experiences, failing to capture how the child feels about the medication.^[34]Practitioner Review: Pharmacological treatment of attention-deficit/hyperactivity disorder symptoms in children and youth with autism spectrum disorder: a systematic review and meta-analysis (Rodrigues et al., 2020). This also means that we do not have much data on stimulant use in adults with AuDHD.

It is also important to point out that the negative side effects are expected to be even higher in the general AuDHD population because most researchers pre-screen autistic individuals and only select study participants who they think will respond well.^[35]Practitioner Review: Pharmacological treatment of attention-deficit/hyperactivity disorder symptoms in children and youth with autism spectrum disorder: a systematic review and meta-analysis (Rodrigues et al., 2020) This careful selection of participants means that the positive findings may not generalize well to the majority of AuDHDers and may even explain why when comparing to the field as a whole, the positive effects “go away”.

Finally, this topic has only been relevant for researchers in the last 10 years. Before 2013, autism couldn’t be co-diagnosed with ADHD. Many older studies looking at stimulant use in ADHD may have actually included undiagnosed autistics!

Summarizing the research

Putting this all together, the research on AuDHD and stimulants is messy. There is a need for newer and more comprehensive study approaches and studies conducted in adults. Based on what we know so far, we can summarize the findings as follows:

• Some AuDHDers find stimulants to be helpful for managing unwanted ADHD traits.
  • Positive effects are more likely in AuDHDers with high IQ, low support needs, and more noticeable ADHD compared to autistic traits.
  • Stimulants may help these individuals process information more quickly.
• However, most AuDHDers do not find stimulants to be as helpful as ADHDers do.
  • Stimulants are generally unhelpful for inattention, impulsivity, and hyperactivity.
• AuDHDers also report more intolerable side effects than ADHDers do, causing many AuDHDers to stop taking the medications.
  • These side effects include irritability, general emotional dysregulation, insomnia, and low appetite.

Deciding whether to try stimulants

If you have AuDHD and would like to try stimulants, don’t let the messy research deter you! There are definitely people who find stimulants to be helpful and you may be one of those people. If you decide that it’s worth trying but then find out that they don’t work or that they cause intolerable side effects, keep in mind that this doesn’t mean there is anything wrong with you or that you “don’t actually have ADHD”. It’s super common for AuDHDers to respond poorly to stimulants.

If you try stimulants and don’t find them helpful, but are looking for other forms of support, here are some options to consider:

• Try multiple kinds. Some people respond well to one type of stimulant but not another. For example, research finds that a lot of AuDHDers respond better to methylphenidates compared to amphetamines.^[36]Practitioner Review: Pharmacological treatment of attention-deficit/hyperactivity disorder symptoms in children and youth with autism spectrum disorder: a systematic review and meta-analysis (Rodrigues et al., 2020)
• Non-stimulant ADHD medications. Some autistics find them to be preferable to stimulants.^[37]Pharmacotherapy in autism spectrum disorders, including promising older drugs warranting trials (Hellings, 2023)
• Seeking out work/school accommodations. You may find that setting yourself up with accommodations, especially at work or at school, is enough to support your needs. You can check out our article about accommodations for some ideas.

Conclusion

This conversation is important for the AuDHD community. There is so much research and discussion about stimulant use in ADHD but this doesn’t exist for AuDHD. Knowing that ADHDers and AuDHDers often respond differently to medications means that this is a major gap in our understanding.

While research catches up, we would love to know about your own experiences. Have you taken stimulants? Did you find them helpful? Or did you experience minimal positive effects and lots of negative effects like me and many other AuDHDers?