The emergence of suicidality in patients receiving drug treatment is of concern because of the overall burden and the possible link with completed suicide. The lack of uniform requirements for defining, detecting and recording suicidality and the presence of disease related confounders create major problems. It is possible that Medication-Related Suicidality (MRS) differs from Psychopathology-Related Suicidality (PRS) in terms of phenomenology, clinical expression and time course, and may vary between children and adults. Unlike PRS, the time-course of MRS may be associated with possible differences in drug pharmacokinetics; abrupt onset; absence of suicidality prior to start of medication; and emergence of suicidality related co-morbidities after treatment.This proposal will focus on developing a web-based comprehensive methodology for the assessment and monitoring of suicidality and its mediators in children and adolescents using the HealthTrackerTM (a paediatric web-based health outcome monitoring system), with the aim of developing a Suicidality Assessment and Monitoring Module, a Bio-psycho-social Mediators of Suicidality Assessment Module, and a Suicidality-Related Psychiatric and Physical Illness Module. The information obtained will be used to computer-generate classification of suicidality using the Classification of Suicide-Related Thoughts and Behaviour (Silverman et al, 2007) and the Columbia Classification Algorithm of Suicidal Assessment (C-CASA) (Posner et al, 2007). The existing Medication Characteristics Module will be expanded to allow documentation of pharmacological characteristics of medication, to explore whether they mediate MRS. The methodology will then be tested in 3 paediatric observational trials (risperidone in conduct disorder; fluoxetine in depression, and montelukast in bronchial asthma) and standardized, which can be used pharmacovigilance and in epidemiological, observational, and registration trials.