Structured diagnostic interviews, which evolved along the development of classification's systems, are now widely used in adult psychiatry, in the fields of clinical trials, epidemiological studies, academic research as well as, more recently, clinical practice. These instruments improved the reliability of the data collection and interrater reliability allowing greater homogenisation of the subjects taking part in clinical research, essential factor to ensure the reproducibility of the results. The diagnostic instruments, conversely to the clinical traditional diagnostic processes allow a systematic and exhaustive exploration of disorders, diagnostic criteria but also severity levels, and duration. The format of the data collection, including the order of exploration of the symptoms, is fixed. The formulation of the questions is tested to be univocal, in order to avoid confusions. In child and adolescent, researches in pharmacology and epidemiology increased a lot in the last decade and the standardisation of diagnostic procedures is becoming a key feature. This Article aims to make an assessment, a selection, and a description of the standardized instruments helping psychiatric diagnosis currently available in the field of child and adolescent's psychiatry. Medline and PsycINFO databases were exhaustively checked and the selection of the instruments was based on the review of four main criteria: i) compatibility with international diagnostic systems (DSM IV and/or ICD-10); ii) number of disorders explored; iii) peer reviewed Journals and iv) richness of psychometric data. After the analysis of the instruments described or mentioned in the literature, 2 structured interviews [the Diagnostic Interview Schedule for Children (DISC) and the Children's Interview for Psychiatric Syndromes (ChIPS)] and 4 diagnostic semi-structured interviews [the Schedule for Affective Disorders and Schizophrenia for School-Age Children (Kiddie-SADS), the Diagnostic Interview for Children and Adolescent (DICA), the Child and Adolescent Psychiatric Assessment (CAPA) and the Interview Schedule for Children and Adolescents ISCA)] were retained according to the 3 first criteria. All can be administered by clinicians, and x out of 6 can also be administered by lay-interviewers. All include a child/adolescent version and a parent version. Two instruments evaluate the presence of DSM IV axe II disorders: The ISCA explores the criteria of the Antisocial Personality Disorder. The CAPA evaluates Borderline, Obsessional-compulsive, Histrionic and Schizotypic Personality Disorders. Regarding the psychometric quality criterion, the selection was much more difficult because of the lack of data and the weakness of the samples studied in reliability studies. Interrater reliability appeared to be good for the 6 instruments, with kappas ranging from 0.5 to 1. This is usual in such instruments. The test-retest reliability was found to vary from bad to excellent depending on the instruments, the "informant" status (child/adolescent or parent), and the disorder explored, kappas ranging from 0.32 to 1. The worst results concerned face-to-face reliability studies which showed weak concordances for the diagnoses, whatever the procedure implemented: Diagnostic interview vs. i) Another diagnostic interview, vs. ii) An expert diagnosis or vs. iii) Scales and questionnaires. Overall, the K-SADS-PL appeared to be the instrument that has the best test-retest reliability for Anxious Disorders and Affective Disorders (the value kappa showing good to excellent reliabilities). Several important methodological observations emerged from this review. Firstly, the metrological data corresponding to the diagnoses according to DSM IV or ICD-10 criteria's were lacking. The face validity was globally satisfactory, but the data concerning their face-to-face validities and their test-retest reliability, although better than in the former versions, were limited because they were tested on small sample. In fact, it appeared that the agreements depend on the informant, the sample studied, the various diagnostic categories and the instrument used. Since the studies carried out by Cohen et al., with now obsolete versions of the DISC and K-SADS, no other study establishing a comparison between two EDS have been conducted. Consequently, the clinicians must be very careful before comparing DSM or ICD diagnoses generated by different instruments. The second point was the length of the interviews that appeared sometimes longer than instruments used in adults, considering the fact that diagnostic procedure implies two independent interviews, one with the child/adolescent and one with the adult referent. The minimum duration was found to be 1 h 30 for the Chips in clinical setting, while it could reach 4 h or more for the DISC IV or the ISCA. The interviews had to be often carried out in several sessions, so the assessment became very difficult in easily tired and/or distractible subjects. The third point referred to the necessity to consider multiple data sources in young patients during the diagnostic procedure, and the weakness of the levels of agreement generally reported between sources. Empirically, it was observed that the investigator granted more weight to the report of the children than to the parent's one, when the clinical judgement was necessary to synthesize the data. On another level, studies showed a high agreement on the factual contents or on the specific events (ex: hospitalization), like on the obvious symptoms (ex: enuresis). The parents report more problems of behaviour, school and relational difficulties, whereas the children report more fear, anxiety, obsessions and compulsions, or delusional ideas. In other words, it appeared that children were better informants in describing their mental states (internalised disorders), and that adults would bring more reliable information in describing externalised disorders. Like McClellan and Werry, we think that further researches are needed to clarify if and when this is the case. The last major point concerned the problem of language. These instruments must be used in the maternal language of the interviewees and they were developed for most of them into English only. For example, there is only one instrument available into French (the Kiddie SADS). Nowadays, it remains difficult to conduct international studies in child and adolescent psychiatry and/or to compare data is this domain. To conclude, the use of the EDS and EDSS brings many benefits, in academic researches as well as in clinical practice, but a more systematic use is limited by a certain number of parameters. The instruments currently available in child and adolescent are far from being optimal in terms of quality and quantity. It seems necessary and useful to contribute to their development and their improvement. In particular, the following points should be considered: drastic reduction of the length of the interviews; simplification in the use of these instruments, during the interviews, but also in the treatment of the data collected during the final phase of diagnosis generation, the clinician having to carry out ceaseless returns to check the presence or not of each diagnostic criterion; reduction of the duration of the highly necessary training, which can be easily solved by the global simplification of the instruments; quantitative and qualitative improvements of psychometric properties, in particular in terms of sensitivity, specificity and face-to-face validity. Finally, it is highly necessary to continue to develop structured diagnostic interviews adapted to the assessment of child and adolescent psychiatric diagnoses keeping in mind simplicity, feasibility and reliability. Developing this kind of instruments is hard, expensive, and sometimes tiresome but it remains the inescapable stage to produce high quality data in the future.