Disruptive or externalizing behavior disorders include Oppositional Defi ant Disorder
(ODD) and Conduct Disorder (CD). Disruptive behaviors in the broader sense, as used in the
present thesis, generally contain three problem domains: attention/hyperactivity problems,
aggressive/oppositional problems, and rule-breaking/conduct problems. The objective of
the studies described in this thesis was to investigate taxonomy of disruptive behavior in
children and adolescents.
In chapter 1, the background and the aims of the studies in this thesis were presented.
Taxonomy is the process of the identifi cation of groups of individuals according to their
properties, hence according to intrinsic criteria, e.g. individual problems or symptoms.
Assessment identifi es the distinguishing features of each individual case, which, in child
and adolescent psychiatry, can be expressed in behavioral, emotional, or physical measures.
Assessment can be used to classify an individual in the proper taxonomic category.
Different approaches to taxonomy in child and adolescent psychiatry are possible, e.g.
the top-down approach of the DSM (Diagnostic and Statistical Manual of Mental Disorders)
system and the bottom-up approach of latent class analysis (LCA), a person-oriented
approach which makes use of categorical latent variables.
In the present thesis, the taxonomy of disruptive behavior in children and adolescents was
investigated, using different samples, different informants, different methods (interviews
as well as questionnaires), and different taxonomic systems. The main research questions
addressed in this thesis were:
− Do the DSM and the LCA approaches to taxonomy of ADHD (Attention-Defi cit/
Hyperactivity Disorder) symptoms yield different or comparable results, especially
regarding the three subtypes of ADHD (inattentive, hyperactive-impulsive, and combined
subtypes)?
− Which taxonomy arises when the LCA approach is applied to teacher-reported inattention
and hyperactivity/impulsivity symptoms in referred children and adolescents?
− To which extent can parents provide information about ADHD symptoms in school,
independently of their vision on the child’s functioning at home; to which extent can
teachers provide information about ADHD symptoms at home, independently of their
vision on the child’s functioning in school?
− Which taxonomy arises when the LCA approach is applied to mother-reported disruptive
behavior in referred adolescents?
− Can a taxonomy of disruptive behaviors in referred children and adolescents found
by application of LCA be validated by studying the outcome of these children and
adolescents?