Among the second generation antipsychotics, aripiprazole presents a new pharmacological profile, basically differentiated by a partial agonist effect on the D2 and D3 dopaminergic receptors. Five short-term efficacy studies, conducted on 1648 patients presenting with schizophrenia or acute relapse of schizoaffective disorders, demonstrated the greater efficacy of aripiprazole than the placebo and comparable efficacy to that of haloperidol and risperidone. The short-term tolerance profile was characterised by a lesser incidence of the extrapyramidal side effects and drowsiness than with haloperidol. Two thousand six hundred and eighty five patients were followed-up over a period of 26 to 52 weeks in five clinical trials versus a placebo and haloperidol, olanzapine, quetiapine and risperiodone: demonstrated efficacy in maintaining the response to treatment and on the delay before relapse was comparable to the other antipsychotics. The classical side effects of antipsychotics decreased in the long-term. Versus olanzapine, a glucid and lipid profile, clearly in favour of aripiprazole, was completed by a lesser incidence of hyperprolactinaemia. Aripiprazole is effective on all the dimensions of schizophrenia: the positive and negative and depressive and anxious symptomatology. It appears to be of interest, notably on the cognitive dimension, which should motivate more in-depth exploration of its place in the treatment in the early stages of schizophrenia. Its therapeutic schedule and the methods of initiation are an essential criterion to the success of treatment, notably during the substitution of other antipsychotics. The clinical and pharmacological originality of aripiprazole would justify the terminology of a "third generation antipsychotic".