This question often comes up because autistic people are at a greater risk for developing mental health problems, and some autism traits overlap with certain mental illnesses. As a result, autism is often not only incorrectly believed to be a mental illness but misdiagnosed as one.
While there can be, and often are, autistic people who have a co-occurring mental health concern, developmental disabilities and mental illnesses are defined, treated, and managed very differently.
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Developmental Disability vs. Mental Illness
According to the Centers for Disease Control and Prevention (CDC), developmental disabilities are “a group of conditions due to an impairment in physical, learning, language, or behavior areas. These conditions begin during the developmental period, may impact day-to-day functioning, and usually last throughout a person’s lifetime.”
Any mental illness, according to the National Institute of Mental Health (NIMH), is “a mental, behavioral, or emotional disorder. A mental illness can vary in impact, ranging from no impairment to mild, moderate, and even severe impairment.”
Serious mental illness, according to the NIMH, is “defined as a mental, behavioral, or emotional disorder resulting in serious functional impairment, which substantially interferes with or limits one or more major life activities.”
Present at birth or before age 18
Symptoms and traits are persistent, day in and day out
May cause physical, cognitive, and/or behavioral challenges
Core traits cannot be cured or effectively treated with medication
Will effect someone for life
May arise at any point in one’s life
Symptoms may be temporary or cyclical
Causes disturbance in thinking and perception
May cause hallucinations and delusions
May be effectively treated with medication
Other Conditions
To further understand the difference between these, it may help to know issues other than autism that are characterized as developmental disorders, as well as some defined as mental illnesses.
Other developmental disorders include:
Other mental illnesses include:
Common Misdiagnoses
Autism is not always a child’s first diagnosis, particularly if they are verbal and of average intelligence. Not infrequently, children who wind up with an autism diagnosis receive a range of other diagnoses first including, in some cases, mental disorders.
There is a simple reason for these misdiagnoses: A child who is bright and verbal may not be evaluated for autism. As a result, the child’s autism traits are viewed not as a set of related challenges, but as individual issues that could potentially be signs of another mental illness.
There are a number of autism traits that share behavior characteristics with other mental illnesses, and can lead to an erroneous diagnosis.
Anxiety-Related Behaviors
Autistic children mayperseverateon particular routines, objects, or phrases. This repetitive behavior is usually a tool for self-calming in autism.
However, the behavior can also seem nearly identical to the anxiety-related behaviors that are a hallmark ofobsessive-compulsive disorder.
Challenges in Social Communication
Autistic children may hyper-focus on their areas of particular interest, essentially ignoring the interests and concerns of others. In autism, this behavior is linked to challenges with social communication.In essence, autistic kids may be unaware that others have thoughts and feelings different from their own.
This could be another potential area of misdiagnosis, however, since the behavior itself can very much resemble some of the self-obsession that may be present innarcissistic personality disorder.
Losing Control of Emotions
Autistic children often lose control of their emotions and experiencemeltdowns(emotional and sometimes violent temper tantrums). In autism, meltdowns are almost always the result of either sensory assaults, anxiety, frustration, or a combination of all three.
In a child who has not been diagnosed with autism, however, the same traits may look likeoppositional defiant disorder, which is considered abehavioral disorder.
Autistic children with low support needs (level 1 autism) may also receive a range of inappropriate diagnoses before receiving their autism diagnosis. Some of the most common include ADHD,hyperlexia, learning disabilities, and speech delays.
It’s important to note that some autistic children with low support needs may not be diagnosed until they are well into their teens or even adulthood. When that happens, it can be tricky. Developmental disabilities usually appear in childhood, and it may be necessary to dig into an individual’s past to unearth signs that these traits existed prior to adulthood.
If childhood information isn’t readily available, it may be impossible to provide an autism diagnosis even if it is the most appropriate diagnosis based on traits and behavior.
Common Conditions Among Autistic People
Though autism may be mistaken for (and misdiagnosed as) a mental illness, it is important to note that it is common for autistic people to have both. In fact, mental illness is more common among autistic people than it is among the general population.
Depression and anxiety are the most common co-occurring mental illnesses for autistic people.
The fact is that for many autistic people, it is anxiety-provoking and depressing to attempt to overcome social, sensory, and/or intellectual challenges that are simply part of who they are.
In addition to mental illness, many autistic children and adults receive additional developmental diagnoses. In many cases, their traits are associated with autism but it is sometimes helpful to know that a child also hasADHD, learning disabilities, hyperlexia, savant syndrome, or another disorder.
A secondary diagnosis, while it may or may not be completely appropriate, can sometimes provide direction for therapy, academic support, and services. Hopefully, in doing so, this could correct any potential misdiagnoses moving forward.
What Makes an Autistic Child a Savant?
9 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Centers for Disease Control and Prevention.Clinical testing and diagnosis for autism spectrum disorder.National Alliance on Mental Illness.Autism.Centers for Disease Control and Prevention.Developmental disability basics.National Institute of Mental Health.Mental illness.Caldwell-Harris CL.An explanation for repetitive motor behaviors in autism: facilitating inventions via trial-and-error discovery.Front Psychiatry. 2021;12:657774. doi:10.3389/fpsyt.2021.657774Rowland, David.The Neurophysical Cause of Autism.Journal of Neurology & Neurophysiology. 2020; Vol.11(5):001-004.National Autistic Society.Meltdowns - A Guide For All Audiences.Rai D, Heuvelman H, Dalman C, et al.Association Between Autism Spectrum Disorders With or Without Intellectual Disability and Depression in Young Adulthood.JAMA Netw Open.2018;1(4):e181465. doi:10.1001/jamanetworkopen.2018.1465Mosner MG, Kinard JL, Shah JS, et al.Rates of Co-occurring Psychiatric Disorders in Autism Spectrum Disorder Using the Mini International Neuropsychiatric Interview.J Autism Dev Disord. 2019;49(9):3819-3832. doi:10.1007/s10803-019-04090-1Additional ReadingBoyle CA, Boulet S, Schieve L, Cohen RA, Blumberg SJ, Yeargin-Allsopp M, Visser S, Kogan MD. Trends in the Prevalence of Developmental Disabilities in US Children, 1997–2008. Pediatrics. 2011; 27: 1034-1042.Patel V, Chisholm D, Dua T, et al., editors.Mental, Neurological, and Substance Use Disorders: Disease Control Priorities, Third Edition (Volume 4). Washington (DC): The International Bank for Reconstruction and Development / The World Bank.Quintero, Maria et al.Co-Occurring Mental Illness and Developmental Disabilities.Social Work Today,Vol. 10 No. 5 P. 6.Scott JG, Mihalopoulos C, Erskine HE, et al.Childhood Mental and Developmental Disorders.
9 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Centers for Disease Control and Prevention.Clinical testing and diagnosis for autism spectrum disorder.National Alliance on Mental Illness.Autism.Centers for Disease Control and Prevention.Developmental disability basics.National Institute of Mental Health.Mental illness.Caldwell-Harris CL.An explanation for repetitive motor behaviors in autism: facilitating inventions via trial-and-error discovery.Front Psychiatry. 2021;12:657774. doi:10.3389/fpsyt.2021.657774Rowland, David.The Neurophysical Cause of Autism.Journal of Neurology & Neurophysiology. 2020; Vol.11(5):001-004.National Autistic Society.Meltdowns - A Guide For All Audiences.Rai D, Heuvelman H, Dalman C, et al.Association Between Autism Spectrum Disorders With or Without Intellectual Disability and Depression in Young Adulthood.JAMA Netw Open.2018;1(4):e181465. doi:10.1001/jamanetworkopen.2018.1465Mosner MG, Kinard JL, Shah JS, et al.Rates of Co-occurring Psychiatric Disorders in Autism Spectrum Disorder Using the Mini International Neuropsychiatric Interview.J Autism Dev Disord. 2019;49(9):3819-3832. doi:10.1007/s10803-019-04090-1Additional ReadingBoyle CA, Boulet S, Schieve L, Cohen RA, Blumberg SJ, Yeargin-Allsopp M, Visser S, Kogan MD. Trends in the Prevalence of Developmental Disabilities in US Children, 1997–2008. Pediatrics. 2011; 27: 1034-1042.Patel V, Chisholm D, Dua T, et al., editors.Mental, Neurological, and Substance Use Disorders: Disease Control Priorities, Third Edition (Volume 4). Washington (DC): The International Bank for Reconstruction and Development / The World Bank.Quintero, Maria et al.Co-Occurring Mental Illness and Developmental Disabilities.Social Work Today,Vol. 10 No. 5 P. 6.Scott JG, Mihalopoulos C, Erskine HE, et al.Childhood Mental and Developmental Disorders.
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Centers for Disease Control and Prevention.Clinical testing and diagnosis for autism spectrum disorder.National Alliance on Mental Illness.Autism.Centers for Disease Control and Prevention.Developmental disability basics.National Institute of Mental Health.Mental illness.Caldwell-Harris CL.An explanation for repetitive motor behaviors in autism: facilitating inventions via trial-and-error discovery.Front Psychiatry. 2021;12:657774. doi:10.3389/fpsyt.2021.657774Rowland, David.The Neurophysical Cause of Autism.Journal of Neurology & Neurophysiology. 2020; Vol.11(5):001-004.National Autistic Society.Meltdowns - A Guide For All Audiences.Rai D, Heuvelman H, Dalman C, et al.Association Between Autism Spectrum Disorders With or Without Intellectual Disability and Depression in Young Adulthood.JAMA Netw Open.2018;1(4):e181465. doi:10.1001/jamanetworkopen.2018.1465Mosner MG, Kinard JL, Shah JS, et al.Rates of Co-occurring Psychiatric Disorders in Autism Spectrum Disorder Using the Mini International Neuropsychiatric Interview.J Autism Dev Disord. 2019;49(9):3819-3832. doi:10.1007/s10803-019-04090-1
Centers for Disease Control and Prevention.Clinical testing and diagnosis for autism spectrum disorder.
National Alliance on Mental Illness.Autism.
Centers for Disease Control and Prevention.Developmental disability basics.
National Institute of Mental Health.Mental illness.
Caldwell-Harris CL.An explanation for repetitive motor behaviors in autism: facilitating inventions via trial-and-error discovery.Front Psychiatry. 2021;12:657774. doi:10.3389/fpsyt.2021.657774
Rowland, David.The Neurophysical Cause of Autism.Journal of Neurology & Neurophysiology. 2020; Vol.11(5):001-004.
National Autistic Society.Meltdowns - A Guide For All Audiences.
Rai D, Heuvelman H, Dalman C, et al.Association Between Autism Spectrum Disorders With or Without Intellectual Disability and Depression in Young Adulthood.JAMA Netw Open.2018;1(4):e181465. doi:10.1001/jamanetworkopen.2018.1465
Mosner MG, Kinard JL, Shah JS, et al.Rates of Co-occurring Psychiatric Disorders in Autism Spectrum Disorder Using the Mini International Neuropsychiatric Interview.J Autism Dev Disord. 2019;49(9):3819-3832. doi:10.1007/s10803-019-04090-1
Boyle CA, Boulet S, Schieve L, Cohen RA, Blumberg SJ, Yeargin-Allsopp M, Visser S, Kogan MD. Trends in the Prevalence of Developmental Disabilities in US Children, 1997–2008. Pediatrics. 2011; 27: 1034-1042.Patel V, Chisholm D, Dua T, et al., editors.Mental, Neurological, and Substance Use Disorders: Disease Control Priorities, Third Edition (Volume 4). Washington (DC): The International Bank for Reconstruction and Development / The World Bank.Quintero, Maria et al.Co-Occurring Mental Illness and Developmental Disabilities.Social Work Today,Vol. 10 No. 5 P. 6.Scott JG, Mihalopoulos C, Erskine HE, et al.Childhood Mental and Developmental Disorders.
Boyle CA, Boulet S, Schieve L, Cohen RA, Blumberg SJ, Yeargin-Allsopp M, Visser S, Kogan MD. Trends in the Prevalence of Developmental Disabilities in US Children, 1997–2008. Pediatrics. 2011; 27: 1034-1042.
Patel V, Chisholm D, Dua T, et al., editors.Mental, Neurological, and Substance Use Disorders: Disease Control Priorities, Third Edition (Volume 4). Washington (DC): The International Bank for Reconstruction and Development / The World Bank.
Quintero, Maria et al.Co-Occurring Mental Illness and Developmental Disabilities.Social Work Today,Vol. 10 No. 5 P. 6.
Scott JG, Mihalopoulos C, Erskine HE, et al.Childhood Mental and Developmental Disorders.
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