Disorders usually first diagnosed in infancy, childhood or adolescence


Mild mental retardation

Moderate mental retardation

Severe mental retardation

Profound mental retardation

Mental retardation; severity unspecified


Reading disorder

Mathematics disorder

Disorder of written expression

Learning disorder

1.3 Motor skills disorders

Developmental coordination disorders

1.4 Communication disorders

Expressive language disorder

Mixed receptive-expressive language disorder


Communication disorder

Pervasive developmental disorders

Autistic Disorder

Rett's disorder

Childhood Disintegrative disorder

Asperger's disorder

Pervasive Developmental disorder

Attention-deficit and disruptive behavior disorders

  • Attention-Deficit Hyperactivity disorder

  • Combined subtype

  • Predominantly hyperactive-impulsive subtype

  • Predominantly inattentive subtype

  • Attention-Deficit Hyperactivity disorder

  • Conduct disorders

  • Childhood onset

  • Adolescent onset

  • Unspecified onset

    Oppositional Defiant disorder

  • Disruptive Behaviour disorder

  • Feeding and eating disorders of infancy or early childhood


  • Rumination disorder

  • Feeding disorder of infancy or early childhood

  • Tic disorders

    Touretet's disorders

  • Chronic motor or vocal tic disorder

  • Transient tic disorder

  • Tic disorder

Elimination disorders

  • Enuresis (not due to a general medical condition)
  • Encopresis, without constipation and overflow incontinence
  • Encopresis, with constipation and overflow incocntience
  • Other disorders of infancy, childhood, or adolescence

  • Separation anxiety disorder

  • Selective mutism

  • Reactive attachment disorder of infancy or early childhood

  • Stereotypic movement disorder

  • Disorder of infancy, childhood, or adolescence


Mental retardation (MR) is a condition diagnosed before age 18, usually in infancy or prior to birth, that includes below-average general intellectual function, and a lack of the skills necessary for daily living. When onset occurs at age 18 or after, it is called dementia, which can coexist with an MR diagnosis. Intelligence level as determined by individual standard assessment is below 70, and the ability to adapt to the demands of normal life is impaired. This is important because it distinguishes a diagnosis of MR from individuals with low IQ scores who are able to adapt to the demands of everyday life. Education, job training, support from family, and individual characteristics such as motivation and personality can all contribute to the ability of individuals with MR to adapt.

Other behavioral traits associated with MR (but not deemed criteria for an MR diagnosis) include aggression, dependency, impulsivity, passivity, self-injury, stubbornness, low self-esteem, and low frustration tolerance. Some may also exhibit mood disorders such as psychotic disorders and attention difficulties, though others are pleasant, otherwise healthy individuals. Sometimes physical traits, like shortness in stature and malformation of facial elements, can set individuals with MR apart, while others may have a normal appearance.

Mental retardation affects about 1 percent to 3 percent of the population.



Learning disabilities are neurologically-based processing problems. These processing problems can interfere with learning basic skills such as reading, writing and/or math.  They can also interfere with higher level skills such as organization, time planning, abstract reasoning, long or short term memory and attention.  It is important to realize that learning disabilities can affect an individual’s life beyond academics and can impact relationships with family, friends and in the workplace.

Since difficulties with reading, writing and/or math are recognizable problems during the school years, the signs and symptoms of learning disabilities are most often diagnosed during that time.  However, some individuals do not receive an evaluation until they are in post-secondary education or adults in the workforce.  Other individuals with learning disabilities may never receive an evaluation and go through life, never knowing why they have difficulties with academics and why they may be having problems in their jobs or in relationships with family and friends.

Learning disabilities should not be confused with learning problems which are primarily the result of visual, hearing, or motor handicaps; of mental retardation; of emotional disturbance; or of environmental, cultural or economic disadvantages.

Generally speaking, people with learning disabilities are of average or above average intelligence. There often appears to be a gap between the individual’s potential and actual achievement. This is why learning disabilities are referred to as “hidden disabilities”: the person looks perfectly “normal” and seems to be a very bright and intelligent person, yet may be unable to demonstrate the skill level expected from someone of a similar age.

A learning disability cannot be cured or fixed; it is a lifelong challenge. However, with appropriate support and intervention, people with learning disabilities can achieve success in school, at work, in relationships, and in the community.



Communication disorders include problems related to speech, language and auditory processing. Communication disorders may range from simple sound repetitions such as stuttering to occasional misarticulation of words to complete inability to use speech and language for communications (aphasia).

Some causes of communication disorders include hearing loss, neurological disorders, brain injury, mental retardation, drug abuse, physical impairments such as cleft lip or palate, emotional or psychiatric disorders, and developmental disorders. Frequently, however, the cause is unknown. It is estimated that one in every 10 Americans, across all ages, races and genders, has experienced or lived with some type of communication disorder (including speech, language and hearing disorders). Nearly 6 million children under the age of 18 have a speech or language disorder.

About Speech

Speech is produced by precise, coordinated muscle actions in the head, neck, chest, and abdomen. Speech development is a gradual process that requires years of practice. During speech development, one learns how to regulate these muscles to produce intelligible speech. It is estimated that by the first grade, 5 percent of children have noticeable speech disorders, the majority of which have no known cause.

One category of speech disorder is dysfluency.

Stuttering is, perhaps, the most serious dysfluency. Stuttering is characterized by a disruption in the flow of speech. It includes repetitions of speech sounds, hesitations before and during speaking and, or, prolongations of speech sounds. There are over 15 million individuals who stutter in the world. Most stutterers first exhibit dysfluency at an early age, and stuttering occurs most frequently in children between the ages of 2 and 6, during language development. One child in 30 goes through a period of stuttering that can last six months or longer.

Articulation difficulties constitute the most numerous of all speech disorders. The term refers to difficulties with the way sounds are formed and strung together ("wabbit" for "rabbit"), omitting a sound ("han" for "hand"), or distorting a sound ("sip for ship")

Voice disorders, another type of speech disorder, relate to difficulties with the quality, pitch and loudness of the voice (prosody). People with voice disorders may have trouble with the way their voices sound. Listeners may have trouble understanding someone with a speech pathology.

Voice is generated by airflow from the lungs as the vocal folds are brought close together. The vocal folds vibrate when air is pushed past them with sufficient pressure. Without normal vibration of the vocal folds in the larynx (voice box), the sound of speech is absent. To produce a whisper, the vocal folds need to be partially separated. It is estimated that 7.5 million people in the United States have difficulties using their voices. Many people who have acquired normal speaking skills become communicatively impaired when their vocal apparatus fails. This can occur if the nerves controlling the functions of the larynx are impaired as a result of an accident, a surgical procedure or a viral infection.

It is important to distinguish between a difficulty in articulation of words and aphasia (a problem with the production of language).

About Language

Language is the expression of human communication through which knowledge, beliefs and behavior can be experienced, explained and shared. A language disorder is the impairment or deviant development of expression and, or, comprehension of words in context. The disorder may involve the form of language, the content of language and, or, the function of language as a communication tool. It is estimated that between 6 and 8 million individuals in the United States have some form of language impairment. Disorders of language affect children and adults differently. For children who do not use language normally from birth, or who acquire the impairment in childhood, the disorder occurs in the context of a language system that is not fully developed or acquired. Many adults acquire disorders of language because of stroke, head injury, dementia or brain tumors. Language disorders are also found in adults who failed to develop normal language because of childhood autism, hearing impairment or other congenital or acquired disorders of brain development.

About Auditory Processing (Hearing)

Auditory processing is the term used to describe what happens in your brain when it recognizes and interprets the sounds around you. Humans hear energy, which we recognize as sound when it travels through the ear and is changed into electrical impulses that can be interpreted by the brain. The "disorder" part of auditory processing disorder (APD) means that something is adversely affecting the processing or interpretation of information.

Children with APD often do not recognize subtle differences between sounds in words, even though the sounds themselves are loud and clear. For example, the request "Tell me how a couch and a chair are alike" may sound to a child with APD like "Tell me how a cow and a chair are alike." It can even be understood by the child as "Tell me how a cow and a hair are alike." These kinds of problems are more likely to occur when a person with APD is in a noisy environment or when he or she is listening to complex information.

APD goes by many other names. Sometimes it is referred to as central auditory processing disorder (CAPD). Other common names are auditory perception problem, auditory comprehension deficit, central auditory dysfunction, central deafness and so-called "word deafness."

Children with APD typically have normal hearing and intelligence.



The term "pervasive developmental disorders," also called PDDs, refers to a group of conditions that involve delays in the development of many basic skills. Most notable among them are the ability to socialize with others, to communicate, and to use imagination. Children with these conditions often are confused in their thinking and generally have problems understanding the world around them.

Because these conditions typically are identified in children around age 3 -- a critical period in a child's development -- they are called developmental disorders. The condition actually starts far earlier than age 3, but parents often do not notice a problem until the child is a toodler,  when differences in children of the same age can be more obvious or noted. These children may still not be walking, talking, or developing in the same way as their peers.

What Conditions Are Considered Pervasive Developmental Disorders?

There are five types of pervasive development disorders: 

Autism : Children with autism have problems with social interaction, pretend play, and communication. They also have a limited range of activities and interests. Many -- nearly three out of every four -- children with autism also have some degree of intellectual disability. Children with autism can frequently have seizures as well as low muscle tone. They also have underlying anxiety  and resistance to change.

  • Asperger's syndrome : Like children with autism, children with Asperger's syndrome have difficulty with social interaction and communication. They also have a narrow range of interests. However, children with Asperger's have average or above average intelligence and develop normally in the areas of language and cognition (the mental processes related to thinking and learning). Children with Asperger's often have difficulty concentrating and may have poor coordination. Asperger's is usually not recognized until children have enough language skills to show a limited focus and unusual patterns of speech.
  • Childhood disintegrative disorder: Children with this rare condition begin their development normally in all areas, physical and mental. At some point, usually between ages 2 and 10, a child with this illness loses many of the skills he or she has developed. In addition to the loss of social and language skills, a child with disintegrative disorder may lose control of other functions, including bowel and bladder control.
  • Rett syndrome : Children with this very rare disorder have the symptoms associated with a PDD and also suffer problems with physical development. They generally suffer the loss of many motor or movement skills -- such as walking and use of their hands -- and develop poor coordination. This condition has been linked to a defect on the X chromosome, so it almost always affects girls.
  • Pervasive development disorder, not otherwise specified (PDD-NOS): This category is used to refer to children who have significant problems with communication and play, and some difficulty interacting with others, but are too social to be considered autistic. It's sometimes referred to as a milder form of autism.
  • What Are the Symptoms of Pervasive Developmental Disorders?

  • The use of the word "pervasive" to describe these illnesses is somewhat misleading. The definition of pervasive is "to be present throughout," but children with PDDs generally do not have problems in all areas of functioning. Rather, most children with PDDs have specific problem areas and often function very well in other areas.

    Children with PDDs, such as autism, can display a wide range of symptoms that range from mild to disabling. They also vary widely in their individual abilities, intelligence, and behavior.

    General symptoms that may be present to some degree in a child with a PDD include:

    • Difficulty with verbal communication, including problems using and understanding language
    • Difficulty with non-verbal communication, such as gestures and facial expressions
    • Difficulty with social interaction, including relating to people and to his or her surroundings
    • Unusual ways of playing with toys and other objects
    • Difficulty adjusting to changes in routine or familiar surroundings
    • Repetitive body movements or patterns of behavior, such as hand flapping, spinning, and head banging
    • Changing response to sound; the child may be very sensitive to some noises and seem to not hear others.
    • Temper tantrums 
    • Difficulty sleeping
    • Aggressive behavior
    • Fearfulness or anxiety 

Attention-deficit and disruptive behavior disorders

Children who have chronic difficulties in maintaining attentional focus, completing work, being impulsive, or repeatedly engage in antisocial behaviors such as lying and cheating may have one or more Attention-Deficit and Disruptive Behavior Disorders. The disorders in this category include Conduct Disorder, Attention-Deficit Hyperactivity Disorder, and Oppositional Defiant Disorder. These three disorders are grouped together within the same category because of similarities between symptoms and prevalence rates For example, children with these disorders often have academic difficulties, poor social skills, and impulsivity (i.e., a tendency to act without thinking through potential consequences). In addition, boys far exceed girls in terms of rates of occurrence (although some researchers suggest that girls with ADHD may be overlooked because they tend to be more inattentive than hyperactive).

The Attention Deficit and Disruptive Behavior Disorders are the most commonly diagnosed disorders of childhood, and make up the majority of referrals of children to mental health treatment services. It used to be thought that the majority of children ultimately "grew out" of these disorders prior to the onset of adulthood. Recently, however, there is an increasing awareness that these disorders often do not disappear as children mature, but rather continue on into adulthood.

Introduction to Conduct Disorder

Conduct Disorder is one of the most frequently diagnosed mental disorders in children. A child with Conduct Disorder engages in repetitive, persistently deviant, impulsive, and/or antisocial behavior that violates the basic rights of other people, or age-appropriate social norms for expected behavior. Children with Conduct Disorder: 1) act aggressively in a way that causes or threatens to cause physical harm to others, 2) cause serious property damage even if they are not actually aggressive towards other adults or children, 3) steal, and are deceitful, and/or 4) frequently violate rules.

Symptoms of conduct disorder vary with age, changing as children develop increased strength, cognitive abilities and sexual maturity. Less severe symptomatic behaviors, such as lying and shoplifting, usually emerge first, while other, more severe behaviors, such as burglary or auto theft, usually emerge later.

Symptoms of conduct disorder may include:

  • Bullying, threatening, or intimidating behavior towards other children
  • Frequent starting of physical fights
  • Use of weapons or tools capable of causing serious physical harm to people or property (e.g., bricks, bats, broken bottles, knives, guns)
  • Physical cruelty toward animals or people
  • Stealing while confronting a victim (e.g., mugging, purse snatching, armed robbery)
  • Physical violence towards others (in the form of rape, assault, homicide, etc.)
  • Destruction of property (e.g., fire setting, breaking of windows, breaking into homes, buildings or cars)
  • Frequent and manipulative telling of lies or breaking of promises in order to obtain goods, favors, or to avoid debts or obligations (e.g., "conning" people)
  • Staying out at night despite parent's curfew rules (before the age of 13)
  • Repeatedly running away from home, or running away from home for a lengthy period of time
  • Use of alcohol or drugs
  • Truancy (skipping school) before the age of 13

According to the DSM, three or more of the above symptoms must be present within the space of 12 consecutive months before a child can receive the diagnosis of Conduct Disorder. In addition, the child's symptoms must also interfere with his or her social or academic functioning.

There are two subtypes of Conduct Disorder: Childhood-Onset Type and Adolescent-Onset Type. TheChildhood-Onset specifier applies when a child has exhibited at least one symptom of the disorder prior to age 10. Most of the children diagnosed with childhood-onset conduct disorder are males who are also physically aggressive. These children usually have disturbed peer relationships and may also be diagnosed with Oppositional Defiant Disorder (see below) during their early childhood years.

In the Adolescent-Onset type, there are no symptoms of the disorder before age 10. These children are less likely to show aggressive behaviors, and usually have more normal peer relationships. Males and females appear develop this subtype at approximately the same rates. Individuals with this subtype also are less likely to have persistent Conduct Disorder or to go on to develop Antisocial Personality Disorder or another personality disorder in adulthood.

Conduct disorder is common, and the number of children diagnosed with this illness has increased over the past few decades. According to the DSM, current prevalence rates for conduct disorder suggest that between 1% and 10% of children will qualify for the diagnosis.

Research suggests that Conduct Disorder is influenced by a combination of genetic and environmental factors. The disorder is more common among biological children of parents diagnosed with Alcohol Dependence, Mood Disorders (such as Major Depression or Bipolar Disorder), Schizophrenia, ADHD, or Conduct Disorder. Individuals with lower verbal intelligence IQ scores and brain-based problems (concentrating, remembering, thinking abstractly, etc.) have an increased chance, statistically, of also qualifying for a simultaneous (co-morbid) diagnosis of Conduct Disorder. These conditions affect how well children are able to solve problems, pay attention, exercise good judgment and to prevent themselves from impulsively engaging in inappropriate but otherwise rewarding (at least in the short term) behaviors.

Environmental triggers of conduct disorder include: family dysfunctions (e.g., exposure to protracted marital conflict, limited financial and emotional resources, instability, and disturbances of family values), peer rejection, and poor performance in school. The environmental triggers of conduct disorder generally come as a package deal. Children who perform poorly in school are often rejected by peers and teachers, fall behind in class, and show a greater likelihood of dropping out of school. The occurrence of any one of these factors lead to a greater likelihood that other behavioral problems will also develop.


Feeding and eating disorders of infancy or early childhood

Avoidant/restrictive food intake disorder (ARFID) is an eating disorder characterized by eating very little food or avoiding eating certain foods. It’s a relatively new diagnosis that expands on the previous diagnostic category of feeding disorder of infancy and early childhood, which was rarely used or studied.

Individuals with ARFID have developed some type of problem with feeding or eating that causes them to avoid particular foods or consuming food altogether. As a result, they aren’t able to take in enough calories or nutrients through their diet. This can lead to nutritional deficiencies, delayed growth, and problems with weight gain. Aside from health complications, people with ARFID may also experience difficulties at school or work due to their condition. They might have trouble participating in social activities, such as eating with other people, and maintaining relationships with others.

ARFID usually presents in infancy or during childhood, and may persist into adulthood. It may initially resemble the picky eating that’s common during childhood. For example, many children refuse to eat vegetables or foods of a certain odor or consistency. However, these picky eating patterns usually resolve within a few months without causing problems with growth or development.

Your child may have ARFID if:

  • the eating problem isn’t being caused by a digestive disorder or other medical condition
  • the eating problem isn’t being caused by a food shortage or cultural food traditions
  • the eating problem isn’t being caused by an eating disorder, such as bulimia
  • they aren’t following the normal weight gain curve for their age
  • they’ve failed to gain weight or have lost a considerable amount of weight within the last month

You may want to schedule an appointment with your child’s doctor if your child is showing signs of ARFID. Treatment is needed to address both the medical and psychosocial aspects of this condition.

When it’s left untreated, ARFID can lead to serious long-term complications. It’s important to get an accurate diagnosis right away. If your child isn’t eating adequately but is at a normal weight for their age, you should still make an appointment with their doctor.


Tic disorders

Many people at some point experience spasm-like movements of particular muscles. These movements, known as tics and twitches, often affect the eyelids or face. They can, though, occur anywhere in the body.

In most instances, tics and twitches are harmless and temporary. In some cases, though, they may be caused by a tic disorder. Tic disorders generally can be managed with treatment and lifestyle changes.

What Are Tics and Twitches?

While many people use the terms tic and twitch interchangeably, there are differences between these two forms of movements.

Tics. There are two types of tics -- motor tics and vocal tics. These short-lasting sudden movements (motor tics) or uttered sounds (vocal tics) occur suddenly during what is otherwise normal behavior. Tics are often repetitive, with numerous successive occurrences of the same action. For instance, someone with a tic might blink his eyes multiple times or twitch her nose repeatedly.

Motor tics can be classified as either simple or complex. Simple motor tics may include movements such as eye-blinking, nose-twitching, head-jerking, or shoulder-shrugging. Complex motor tics consist of a series of movements performed in the same order. For instance a person might reach out and touch something repeatedly or kick out with one leg and then the other.

Tics are often classified not as involuntary movements but asunvoluntary movements. This means that people are able to suppress the actions for a time. The suppression, though, results in discomfort that grows until it is relieved by performing the tic.

While people of all ages can experience tics, they are most prevalent in children. Experts say that around 25% of children experience tics. And tics are far more likely to affect boys than girls.

No one knows exactly what causes tics to occur. Stress and slleep deprivation seem to play a role in both the occurrence and severity of motor tics.

Doctors once believed that certain  medications, including some used to treat attention deficit hyperactivity disorder, induced tics in children that were prone to them. Newer studies, though, suggest this is not the case.

Twitches. Unlike tics, the majority of muscle twitches are isolated occurrences, not repeated actions. Muscle twitches are also known as myoclonic jerks. They are entirely involuntary and cannot be controlled or suppressed.


Elimination disorders

What Are Elimination Disorders?

Elimination disorders occur in children who have problems going to the bathroom -- both defecating and urinating. Although it is not uncommon for young children to have occasional "accidents," there may be a problem if this behavior occurs repeatedly for longer than three months, particularly in children older than 5 years.

There are two types of elimination disorders, encopresis and enuresis.

  • Encopresis is the repeated passing of feces into places other than the toilet, such as in underwear or on the floor. This behavior may or may not be done on purpose.
  • Enuresis is the repeated passing of urine in places other than the toilet. Enuresis that occurs at night, or bed-wetting, is the most common type of elimination disorder. As with encopresis, this behavior may or may not be done on purpose.
  • What Are the Symptoms of Encopresis?

    In addition to defecating in improper places, a child with encopresis may have other symptoms, including:

    • Loss of appetite
    • Abdominal pain 
    • Loose, watery stools (bowel movements)
    • Scratching or rubbing the anal area due to irritation from watery stools
    • Decreased interest in physical activity 
    • Withdrawal from friends and family
    • Secretive behavior associated with bowel movements 

    What Causes Encopresis?

    The most common cause of encopresis is chronic (long-term)constipation, the inability to release stools from the bowel. This may occur for several reasons, including stress, not drinking enough water (which makes the stools hard and difficult to pass), and pain caused by a sore in or near the anus.

    When a child is constipated, a large mass of feces develops, which stretches the rectum. This stretching  dulls the nerve endings in the rectum, and the child may not feel the need to go to the bathroom or know that waste is coming out. The mass of feces also can become impacted -- too large or too hard to pass without pain. Eventually, the muscles that keep stool in the rectum can no longer hold it back. Although the large, hard mass of feces cannot pass, loose or liquid stool may leak around the impacted mass and onto the child's clothing.