Obsessive-compulsive disorder (OCD) is estimated to affect between 0.5% and 2% of children and adolescents. The majority of clinical cases has both obsessions and compulsions. Depression, anxiety and tic disorders are common comorbid diagnoses, and assessment can therefore be complex. Several theories have been proposed for the aetiology and maintenance of the disorder, including cognitive-behavioural and neuropsychiatric theories. Cognitive-behavioural and pharmacological treatments are both probably efficacious therapies for children and adolescents but further research is needed to compare these treatments with each other, and to examine the use of combination therapies in controlled trials.

Professionals working in child and adolescent mental health services are increasingly encouraged to examine the evidence underlying their clinical practice. Embracing evidence-based practice can present difficulties, as barriers to changing practice exist. These difficulties are examined, along with the meaning of evidence-based practice in a multidisciplinary speciality, and the potential benefits that develop from it.

The argument for evidence-based child and adolescent mental health services is irresistible. Indeed, I have yet to meet a mental health practitioner who has told me that his or her work was not based on evidence. The exam question, however, is ‘what is the best evidence?’ In a helpful contribution to the current debate about evidence-based practice, Ramchandani, Joughin and Zwi point out that the answer depends on what the question was in the first place. They argue that while some clinical questions are best tackled using quantitative methods such as randomised trials, other questions are better answered using different techniques. Traditional hierarchies of evidence that give primacy to randomised trials may not always be appropriate to child mental health practice.

Reviews of the literature on attention-deficit/hyperactivity disorder (ADHD) typically begin early in the twentieth century with the descriptions provided by paediatrician George Still. Physician Alexander Crichton, however, described all of the essential features of the Inattentive subtype of ADHD more than a century earlier than Still. This article presents a short biography of Crichton, looks at his 1798 publication describing attentional disorders in otherwise healthy individuals, contrasts his medical writing with the moralism of Still, and shows how his thoughts and observations are very much in accord with DSM-IV criteria for the Inattentive subtype of ADHD.

This review outlines some of the difficulties involved in assessing preschool children's language development. Language is a sensitive indicator of a range of developmental difficulties yet the accurate identification of children who are experiencing delays or disorders is problematic. A range of different approaches are used to identify and assess language problems including norm-referenced assessments, questionnaires and language samples. Each of these is critically evaluated. In particular the reliability and validity of the measures and their ability to discriminate atypical patterns of development is considered. It is concluded that there are no simple assessment tools that identify and assess language development. Moreover, the use of single measures is considered inadequate for determining whether a child at any age has typical or delayed language. Ways to circumvent the limitations of the assessment tools are considered.

When Philip Graham takes up the Chair of the Association next June, it will be his second term in an office he originally held in 1982. Although he would modestly deny it, he is not only one of the UK's leading child and adolescent psychiatrists, but also widely respected internationally. Outside this country his reputation is particularly strong in Europe where he was President of the European Society for Child and Adolescent Psychiatry from 1987 to 1991. His appointment to the Foundation Chair of Child Psychiatry at the Institute of Child Health in 1975 marked the establishment of the second such chair in the UK. The esteem in which he was held there led to his appointment as Dean of the Institute from 1985 to 1990. On retirement in 1994 he was elected to the Chair of the National Children's Bureau, reflecting his broad perspective on the welfare of children.