An autism diagnosis may be challenged by the presence of other disorders. These may overlap with, overshadow, or mimic one another.

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There is no lab test for autism spectrum disorder (ASD). Rather, an ASD diagnosis is given after careful observation of symptoms and behaviors.

But sometimes, this may be more difficult than it sounds.

ASD exists on a spectrum and involves a wide range of symptoms and varying degrees of challenges. It’s also common for autistic people to have other disorders at the same time. Plus, autism may overlap or be overshadowed by other conditions.

This can make its identification more complex, potentially leading to missed or incorrect diagnoses.

ASD is a neurodevelopmental disorder affecting about 1.5% of the population. Since researchers began tracking the disorder in 2000, ASD diagnoses have steadily increased, primarily due to its growing awareness among the general public and the scientific community.

ASD can look very different from person to person. Each individual exhibits a unique set of symptoms and different degrees of severity.

This in itself can make an ASD diagnosis challenging, sometimes leading to:

  • a missed diagnosis
  • an incorrect diagnosis (misdiagnosis)
  • a late diagnosis

One of the biggest challenges is the co-occurrence of other disorders. About 70% to 80% of autistic people with milder forms of ASD are also diagnosed with another psychiatric condition. In fact, more than half of young autistic children have four or more other conditions.

A 2020 review study found the following prevalence rates of other psychiatric conditions in autistic people:

In addition, ASD and certain conditions may overshadow or even shape one another. For example, evidence from 2021 suggests that ASD may share a common developmental root with other disorders, be a basis for other conditions to flourish, or both.

For instance, the 2021 study cites research that has confirmed that ASD is a risk factor for conditions such as:

  • anxiety
  • depression
  • trauma- or stress-related symptoms
  • suicidal thoughts

These secondary conditions frequently arise due to the high levels of stress experienced by autistic people — often the result of difficulties with interpersonal and communication skills. In some cases, ASD may be overlooked while the secondary condition, such as depression, is diagnosed.

Gender may also play a role. Research from 2021 that grouped participants into male and female categories indicated that ASD symptoms in females are more likely to be overlooked or misdiagnosed.

This is linked to several factors:

  • Diagnostic tools are designed to identify symptoms commonly seen in males (due to mostly male samples in research).
  • Females are more likely to have internalizing symptoms, rather than externalizing symptoms, which could be confused with anxiety or depression.
  • Females have less obvious social and communication difficulties.

There may also be racial or ethnic disparities leading to missed diagnoses.

One 2019 study looked at the education and medical records of 266,000 children who were 8 years old in 2014. Of the 4,500 children researchers identified as having ASD symptoms, 25% had not been diagnosed or treated. These children were primarily Black and Hispanic males.

Before receiving an ASD diagnosis, many autistic people are misdiagnosed with a variety of conditions.

Research from 2020 has shown that adults who received an ASD diagnosis had frequently received diagnoses for:

The following disorders share many of the same symptoms as autism, which may result in a misdiagnosis:

  • ADHD. ASD shares several symptoms with ADHD, including difficulties with impulsivity, executive functioning, and hyperactivity. They also frequently co-occur.
  • Avoidant personality disorder, social anxiety disorder, shyness. Many autistic people have difficulty with social interaction. They may also prefer solitude, making them appear withdrawn or shy.
  • OCD. ASD often involves repetitive or ritualistic behaviors, which may look like OCD. These disorders also frequently co-occur. A 2020 study found that 9% of autistic participants had OCD, and in one 2018 study, 27.8% of people with OCD had undiagnosed ASD.
  • Schizophrenia spectrum disorders. Sensory issues in autistic people may be misdiagnosed as hallucinations in schizophrenia. It can also be difficult to tell the difference between the negative symptoms of schizophrenia and ASD symptoms.
  • Eating disorders. Autistic people often have food sensitivities and ritualistic eating behaviors, which may look like an eating disorder.
  • Personality disorders. This may be due to difficulties handling emotions or relating to other people.
  • Mood disorders. Many autistic people experience mood episodes, such as anger or depression, which might look like bipolar disorder.
  • Generalized anxiety disorder (GAD). Autistic people commonly experience tension and anxiety. Research from 2017 shows that 11% to 84% of autistic folks experience anxiety.
  • Language-based learning disabilities. Autistic people often have difficulties with verbal and nonverbal expressions.
  • Intellectual disability. Intellectual disability shares symptoms with ASD in social communication differences and repetitive behaviors.

Autism is a spectrum of various symptoms that may appear mild to severe. Below are some of the more common symptoms of autism:

  • difficulty interpreting what others are thinking or feeling (including body language, facial expressions, and social cues)
  • intense special interests
  • repetitive or ritualistic behaviors
  • trouble managing and regulating emotions
  • difficulty understanding idioms or nonliteral language
  • difficulty with conversational skills (keeping a conversation going or the natural give-and-take of a conversation)
  • strict daily routines or becoming emotionally distressed when routines are changed
  • trouble with using vocal or emotional inflection while speaking

If you believe you or your child has been misdiagnosed with autism, it’s important to discuss it with a doctor, your child’s pediatrician, or a mental health professional. You can let your doctor know why you believe a misdiagnosis has occurred and what you think the symptoms may actually point to.

If you think you’re autistic but have never received a diagnosis, consider writing down your symptoms and presenting the list to a doctor. Your doctor may refer you to a specialist for more testing.

If your healthcare professional dismisses your concerns, consider getting a second opinion.

Autism spectrum disorder affects about 1.5% of the population. It has a wide range of symptoms that may overlap with other conditions, making a misdiagnosis more likely.

Some autistic people have more severe levels of challenges, while others have milder symptoms that blend in with the neurotypical population. In fact, some autistic people with milder forms of ASD aren’t diagnosed until adulthood, when social or life demands may exceed their coping skills.

But whether a diagnosis is given in childhood or adulthood, the important thing is getting the correct diagnosis. As research continues to shed new light on autism, diagnostic tools will continue to improve, allowing people to receive earlier diagnoses and get the support they need or want to receive.