What is the Diagnostic Classification of Mental Health and Developmental Disorder of Infancy and Early Childhood?


The Diagnostic Classification of Mental Health and Developmental Disorders of Infancy and Early Childhood (DC) is a developmentally based diagnostic manual that provides clinical criteria for categorising mental health and developmental disorders in infants and toddlers.

It is organised into a five-part axis system. The book has been translated into several languages and its model is widely adopted for the assessment of children of up to five years in age.

The DC 0-3R is meant to complement, but not replace, the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR), and the International Statistical Classification of Diseases and Related Health Problems (ICD-10) of the World Health Organisation (WHO). It is intended to enhance the understanding of young children by making it possible to assess, diagnose, and treat mental health problems in infants and toddlers by allowing for the identification of disorders not addressed in other classification systems.

The DC is organised around three primary principles:

  1. That children’s psychological functioning unfolds in the context of relationships;
  2. That individual differences in temperament and constitutional strengths and vulnerabilities play a major role in how children experience and process events; and
  3. That the family’s cultural context is important for the understanding of the child’s developmental course.

Brief History

Originally published in 1994, ZERO TO THREE’s Diagnostic Classification of Mental Health and Developmental Disorders of Infancy and Early Childhood (DC:03) was the first developmentally based system for diagnosing mental health and developmental disorders of infants and toddlers (i.e. 0 to 3).

The revised DC:03, published in 2005 (DC:03R) drew on empirical research and clinical practice that had occurred worldwide since the 1994 publication and extended the depth and criteria of the original DC:03.

DC:05 captures new findings relevant to diagnosis in young children and addresses unresolved issues in the field since DC:03R was published in 2005.

DC:05 is designed to help mental health and other professionals: recognize mental health and developmental challenges in infants and young children, through 5 years old; understand that relationships and psychosocial stressors contribute to mental health and developmental disorders and incorporate contextual factors into the diagnostic process; use diagnostic criteria effectively for classification, case formulation, and intervention; and facilitate research on mental health disorders in infants and young children. DC:05 enhances the professional’s ability to prevent, diagnose, and treat mental health problems in the earliest years by identifying and describing disorders not addressed in other classification systems and by pointing the way to effective intervention approaches. Individuals across disciplines, mental health clinicians, counsellors, physicians, nurses, early interventionists, social workers, and researchers will find DC:05 to be an essential guide to evaluation and treatment planning with infants, young children, and their families in a wide range of settings.

The Diagnostic Process

The diagnostic process is one that is ongoing and done over a period of time. The process includes gathering a series of information regarding the child’s behaviour and presenting problems. The information is collected by a clinician and pertains to the child’s adaptation and development across different occasions and contexts.

According to the DC, the diagnostic process consists of two aspects:

  1. The classification of disorders; and
  2. The assessment of individuals.

One of the primary reasons for the classification of disorders is to facilitate communication between professionals. Once a diagnosis has been made, a clinician can then make associations between their clients’ symptoms and previously existing knowledge regarding the disorders’ aetiology, pathogenesis, treatment, and prognosis. Furthermore, using the classification of disorders can facilitate the process of finding existing services and mental health systems that are appropriate for the particular needs of the affected child. The assessment of children thus becomes a pivotal process that is undertaken by clinicians in order to grant access to treatment and intervention services related to specified disorders.

Clinical assessment and diagnosis involves making observations and gathering information from multiple sources relating to the child’s life in conjunction with a general diagnostic scheme. Both the DSM and ICD classification systems have evolved to use a multiaxial scheme, thus, clinicians have been using them not only for the classification of disorder but also as a guide for assessment and diagnosis. The first three axes of the DSM and ICD relate to the classification of disorder, and the fourth and fifth relate to the assessment of the individual within their personal environment. Similarly, the DC also follows a multiaxial scheme.


The DC 0-3R provides a provisional diagnosis system, focusing on multi-axial classification. The system is a provisional system because it recognises the fluidity and change that may occur with more knowledge in the field. This classification system is not entirely synonymous with the DSM-IV and the ICD-10, because it concentrates on developmental issues. There is also an emphasis placed on dynamic processes, relationships, and adaptive patterns within a developmental framework. The use of this classification system imparts knowledge about the diagnostic profile of a child, and the various contextual factors that may contribute to difficulties.

The DC functions as a reference for the earlier manifestations of problems in infants and children, which can be connected to later problems in functioning. Secondly, the categorisation focuses on types of difficulties in young children that are not addressed in other classification models.

The diagnostic categories vary in description, with more familiar categories described less. Categories that are more specific to young childhood and infancy, and newly based on clinical approaches are described in more detail. Furthermore, some categories may have subtypes to promote research, clinical awareness, and intervention planning, whereas others do not. This is important information to keep in mind when reading the DC.

The Multi-Axial System

Axis I: Clinical Disorders

Axis 1 of the DC provides diagnostic classifications for the most primary symptoms of the presenting difficulties. These diagnoses focus on the infant or child’s functioning. The primary diagnoses include:

  1. Posttraumatic Stress Disorder:
    • This refers to children who may be experiencing or have experienced a single traumatic event (e.g. an earthquake), a series of traumatic events (e.g. air raids), or chronic stress (e.g. abuse).
    • Furthermore, the nature of the trauma and its effect on the child must be understood in the context of the child. Specifically, attention must be paid to factors such as social context, personality factors, and the caregivers’ ability to assist with coping.
  2. Disorders of Affect:
    • This classification of disorders is related to the infant or child’s affective and behavioural experiences.
    • This group of disorders includes mood disorders and deprivation/maltreatment disorder.
    • This classification focuses on the infant or child’s functioning in its entirety rather than a specific event or situation (refer to Affective spectrum).
  3. Adjustment Disorder:
    • When considering a diagnosis of adjustment disorder, one has to examine the situational factors to determine if it is a mild disruption in the child’s usual functioning (e.g. switching schools).
    • These difficulties must also not meet the criteria for other disorders included in the categories.
  4. Regulation Disorders of Sensory Processing:
    1. The child manifests difficulties in regulating behavioural, motor, attention, physiological, sensory, and affective processes.
    2. These difficulties can affect the child’s daily functioning and relationships (refer to Sensory processing disorder).
  5. Sleep Behaviour Disorder:
    • To diagnose a sleep disorder, the child should be showing a sleep disturbance and not be demonstrating sensory reactive or processing difficulties.
    • This diagnosis should not be used when sleep problems are related to issues of anxiety or traumatic events.
  6. Eating Behaviour Disorder:
    • This diagnosis may become evident in infancy and young childhood as the child may show difficulties in regular eating patterns.
    • The child may not be regulating feeding with physiological reactions of hunger. This diagnosis is a primary diagnosis in the absence of traumatic, affective, and regulatory difficulties (refer to eating disorder).
  7. Disorders of Relating and Communicating:
    • These disorders involve difficulties in communication, in conjunction with difficulties in regulation of physiological, motor, cognitive, and many other processes.

Axis II: Relationship Classification

Axis II focuses on children and infants developing in the context of emotional relationships. Specifically, the quality of caregiving can have a strong impact in nurturance and steering a child on a particular developmental course, either adaptive or maladaptive. This particular axis concentrates on the diagnosis of a clinical issue in the relationship between the child and the caregiver. The presence of a disorder indicates difficulties in relationships. These disorders include various patterns that highlight behaviour, affective, and psychological factors between the child and the caregiver.

  • Overinvolved.
  • Underinvolved.
  • Anxious/Tense.
  • Angry/Hostile.
  • Mixed Relationship Disorder.
  • Abusive.

Axis III: Medical and Developmental Disorders and Conditions

Axis III focuses on physical, mental, or developmental classification using other diagnosis methods. These disorders and conditions are not treated as a single diagnosis, but as a problem that may co-exist with others, as it may involve developmental difficulties.

Axis IV: Psychosocial Stressors

This axis allows clinicians to focus on the intensity of psychosocial stress, which may act as influencing agents in infant and childhood difficulties/disorders. Psychosocial stress can have direct and indirect influences on infants and children, and depends on various factors.

Axis V: Emotional and Social Functioning

Emotional and social functioning capacities can be assessed using observations of the child with primary caregivers. The essential domains of functioning can be used in these observations on a 5-point scale, that describes overall functional emotional level.

Rating Scales and Checklists

The DC contains four forms that aid clinicians in identifying disorders in infants and toddlers, in examining the extent of problem behaviours, and in determining the nature of external factors influencing the child.

  • Functional Rating Scale for Emotional and Social Functioning Capacities: to evaluate the child’s communication skills and expressions of thoughts and feelings.
  • The Parent-Infant Relationship Global Assessment Scale (PIR-GAS; from Axis II): to evaluate the quality of a caregiver-child relationship and identify relationship disorders.
  • Relationship Problems Checklist (RPCL; from Axis II): allows the clinician to identify the extent to which a caregiver-child relationship can be described by a number of criterion-based qualities.
  • Psychosocial and Environmental Stressors Checklist (from Axis IV): to provide information on the stressors experienced by the child in various contexts.

The Future of DC

Important questions remain to be answered, in spite of the revisions made in the DC. Such questions include the following:

  • How can the functional adaptation of infants and children be evaluated and described independent of diagnosis?
  • How can disruptive behaviours of typical development in infants and children be distinguished from disordered behaviours that lead to atypical development?
  • Should Excessive Crying Disorder be considered as a functional regulatory disorder? Other functional regulatory disorders include Sleeping Behaviour and Feeding Behaviour Disorders.
  • Should future editions of the DC include a Family Axis containing information about family history of mental illness, family structure and available supports, and family culture? These aspects are all central to assessment and treatment planning.

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