AbstractThis review aims to describe the importance of i) detecting individuals at clinical high-risk for psychosis (schizophrenia) or bipolar disorder, especially in children and adolescents, in order to enable early intervention, and ii) evaluating different intervention strategies, especially pharmacotherapy, during the subsyndromal or “prodromal” stages of these severe and often debilitating disorders. The different approaches regarding the psychotic and bipolar clinical high-risk state are discussed, including reasons and evidence for early (pharmacological) intervention and risks of treatment vs. non-treatment. Only 10 prospective studies of antipsychotics (randomized=4) and 6 prospective studies of non-antipsychotic pharmacologic agents (randomized=3, i. e., omega-3 fatty acids=2, glycine=1) for the psychotic clinical high-risk state and only 4 prospective studies of mood stabilizing medications for the bipolar clinical high-risk state (randomized=2, i. e., lithium=1, valproate=1) were detected. Based on the minimal efficacy data, adverse effect risks, especially in pediatric populations, nonspecific psychopathology, and unknown true risk for the development of either psychosis or bipolar disorder or of chronically disabling symptoms and disability, medication treatment currently remains second choice after psychosocial intervention. Additional research in this area is clearly needed in order to shed more light on the relevance and predictive value of potentially prodromal symptoms, their identification and most appropriate management options.