How Do Developmental Disorders Differ from Mental Illnesses?

Updated June 27, 2023 · 1 Min Read

Explore this resource by Best Counseling Degrees to learn all about develeopmental disorders vs mental illness. is an advertising-supported site. Featured or trusted partner programs and all school search, finder, or match results are for schools that compensate us. This compensation does not influence our school rankings, resource guides, or other editorially-independent information published on this site.

Are you ready to discover your college program?

It is relatively easy to distinguish between medical conditions that are purely physical, in part because they are visibly obvious. Whether an individual is wearing a cast or a sling, an observer can clearly identify the condition as an arm injury. When it comes to the kind of conditions treated largely by counseling and psychology, differences are less apparent. Many people don’t understand the distinctions between mental illnesses and developmental disorders. As an aspiring counselor, you may help patients with either kind of disorder, or with a combination of disorders, so it’s important to understand the differences.

Differences between Developmental Disorders and Mental Illnesses

A well-known example of developmental disorders is autism, according to Mental illnesses include mood disorders such as depression and anxiety disorders and psychotic disorders such as schizophrenia, according to WebMD. Because both developmental disorders and mental illnesses affect thought processes and behavior, many people lump these different types of conditions together.

A key difference is that developmental disorders and mental illnesses thought processes and behavior in different ways, as the Intellectual Disability Rights Service illustrates. In the case of pervasive developmental disorders, individual with the disorder do not have the cognitive ability to have or understand certain thoughts. A developmental disorder may be an obstacle to learning. In contrast, a mental illness does not directly impact cognitive abilities, but instead changes an individual’s perceptions and thought processes. A child with a developmental disorder but no mental illness will typically not “hear voices” or otherwise have hallucinations, just as an individual with depression may lose motivation to engage in situations but will not lose the cognitive ability to understand those situations.

Developmental disorders are diagnosed when a patient is younger than 18 years of age. Mental illnesses can affect people of any age. While children can suffer from mental illnesses, these conditions can just as easily begin during adulthood. Additionally, these disorders differ in duration. Developmental disorders are lifelong disabilities. Mental illnesses may not be lifelong. Some are chronic while others are temporary or recur in episodes, but are not omnipresent.

Featured Online Programs

Figuring out where to apply? These top, accredited schools offer a variety of online degrees. Consider one of these accredited programs, and discover their value today.

Similarities between Developmental Disorders and Mental Illnesses

Both developmental disorders and mental illnesses are diagnosed by psychology professionals, though whether it’s a counselor, therapist, psychologist or psychiatrist that diagnoses and treats a given patient may vary. The Diagnostic and Statistical Manual of Mental Disorders (DSM), which is the book widely used to diagnose medical conditions in the realm of psychology and psychiatry, covers diagnosis of both types of disorders.

When you become a counselor, you may work with patients experiencing a variety of problems, from mental illnesses to developmental disorders. Some patients may suffer from multiple conditions, including combinations of developmental disorders and mental illnesses. During your education, the curriculum in your counseling degree program will help you understand the intricacies of diagnosing and treating developmental disorders and mental illnesses so that you can help every patient that comes to you to the best of your ability.

Learn More:

  • Characteristics of a Narcissist
  • Latest Posts

    Are you ready to do impactful work in your community?