The Differences Among Mental, Developmental, and Behavioral Conditions

Mental, developmental, and behavioral conditions often get grouped together because they affect thought processes and behavior. 

Developmental disabilities and behavioral disorders might have negative impacts on a child’s mental health, resulting in mental illness.

Like mental illnesses, some developmental disabilities and behavioral disorders are diagnosed and treated by mental health professionals, including therapists, psychologists, and psychiatrists. They can also be found in the Diagnostic and Statistical Manual of Mental Disorders, which is used to diagnose mental conditions. 

The term “dual diag­nosis” is often used to refer to children and adults who have developmental disability and/or behavioral difficulties with co-occurring mental illness. While these conditions can affect children in similar ways, they are very much different.

According to the Centers for Disease Control and Prevention (CDC):

  • Having another disorder is most common in children with depression: about 3 in 4 children aged 3-17 years with depression also have anxiety (73.8%) and almost 1 in 2 have behavior problems (47.2%).
  • For children aged 3-17 years with anxiety, more than 1 in 3 also have behavior problems (37.9%) and about 1 in 3 also have depression (32.3%).
  • For children aged 3-17 years with behavior problems, more than 1 in 3 also have anxiety (36.6%) and about 1 in 5 also have depression (20.3%).

Details and Differences

Mental Illness

Mental health disorders affect mood, thought processes, or behavior and can manifest in anyone at any time in their life. Mental illness does not directly impact cognitive abilities like some developmental disabilities, but they can change a person’s perceptions and thought processes and affect a person’s everyday functioning and ability to relate to others. While children can suffer from mental illnesses, these conditions can just as easily begin during adulthood and they may not be lifelong. 

Examples of mental illnesses that affect children: anxiety, attention-deficit/hyperactivity disorder (ADHD), depression, obsessive compulsive disorder (OCD), post-traumatic stress disorder. 

Developmental Disabilities

According to the US Center 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 include intellectual disabilities and physical disabilities. Some developmental disabilities begin before birth but all occur during the developmental period and continue throughout the person’s life. 

Examples of developmental disabilities that affect children: Autism Spectrum Disorder (ASD), vision impairment, cerebral palsy, hearing loss, and Down Syndrome.

Behavioral Disorders

Behavior disorders in children are diagnosed when the conduct becomes extreme and is considered pathological.  The primary difference between a behavior disorder and another type of psychiatric disorder is the presence of choice. Psychiatric conditions are considered to be involuntary while in behavior disorders, choices are essential. 

Examples of behavior disorders that affect children: oppositional defiant disorder (ODD) and conduct disorder (CD).

More Information

More information about mental, developmental, and behavioral conditions can be found on the CDC website.


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