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Editorial: Preschool behaviour problems - over-pathologised or under-identified? A developmental psychopathology perspective is needed.

Child psychopathology differs from adult psychopathology in many ways. Taking into account developmental aspects of psychopathology is of utmost importance for clinicians and researchers. The meaning of a specific behaviour varies across developmental periods as criteria for normal behaviour are age-dependent, and expression of psychopathology in children often changes in both type and intensity as a result of varying developmental capacities and demands across time (Rutter & Sroufe, 2000). However, current psychiatric classification systems tend to view childhood disorders as downward extensions of adult or adolescent disorders without taking into account developmental variations, age-specific aspects or setting considerations in characterising symptoms. Owing to the high level of behavioural variation and the enormous changes in organisation of behaviour during early childhood, the diagnostic challenge to differentiate psychopathological forms of preschool disruptive behaviour from early child temperament features and the broad range of normative misbehaviours poses a particular problem for the current psychiatric classification systems. Clinically, the question of whether, and under what circumstances, it is appropriate to apply the diagnostic category of disruptive behaviour disorder in preschool children is a crucial one. The answer should balance between the risk of over-pathologising normal behaviour in young children that represents developmentally deviant but transient manifestations of dysfunction on the one hand, and the risk of missed opportunities for early recognition of clinically significant indicators for the later onset of a full-blown disorder and appropriate early intervention on the other. Early identification and intervention might be regarded as particularly necessary, as disruptive behaviour syndromes not only constitute one of the most common diagnoses in preschool children and a major public health problem, but have also been regarded as relatively resistant to treatment interventions at a later age. In the first paper in this issue, Wakschlag, Tolan, and Leventhal point out that a developmentally specified nosology is needed for an improved identification of preschool disruptive behaviour. In their research review, they argue against an application of a uniform symptom set of symptoms to early childhood that may ‘falsely suggest continuity, whereas, in fact, it has poorly identified early childhood disruptive behavior because its determination rests either on extreme, rarely occurring behaviors or commonly occurring normative misbehaviors’. Features of problem behaviour beyond frequency are critical for distinguishing typical and atypical patterns. Wakschlag and colleagues illustrate that, rather than solely relying on occurrence or frequency criteria for a certain – broadly defined – problem behaviour, the consideration of its quality – operationalised in terms of its modulation, i.e., its intensity, flexibility to environmental input, and organisation – is necessary to differentiate clinical presentation of disruptive behaviour from normal behaviour and other syndromes. Their refined conceptualisation of disruptive behaviour disorders simultaneously considers developmental deviations in four continuous dimensions of misbehaviour, namely temper loss, aggression, non-compliance, and low concern for others, to differentiate emergentpsychopathology from normative variation in emotional and behavioural regulation and control, rather than taking a more narrow focus on a few extreme behaviours as symptomatic. Their developmentally specified, multidimensional approach to preschool disruptive behaviour can be considered as paradigmatic for developmental specification of child psychiatric disorders across the lifespan. Whether this approach will also enhance our ability to reliably characterise and differentiate subgroups with distinct aetiologies and developmental courses into persistence in and desistance from later psychopathology, and differential treatment responses, is a question for future research. Its risk is an expanding complexity. For further improvement of our knowledge on developmental processes in both normal development and psychopathology, a multiple-levels-of-analysis approach taking into account neurobiological mechanisms "the diagnostic challenge to differentiate psychopathological forms of preschool disruptive behaviour from early child temperament features and the broad range of normative misbehaviours poses a particular problem for the current psychiatric classification systems." Journal of Child Psychology and Psychiatry 51:1 (2010), pp 1–2 doi:10.1111/j.1469-7610.2009.02206.x