Atypical antipsychotics have become the treatment of choice for patients experiencing a first episode of schizophrenia. In addition, they are often prescribed for conditions such as bipolar disorder and dementia. While clinical trials have not yet established the efficacy of the atypical antipsychotics for these uses, a number of reports offer preliminary evidence that the atypical antipsychotics may be beneficial for affective disorders, substance abuse disorder, senile dementia, and pathologic aggression. Atypical agents may be particularly effective and tolerable in elderly patients who are especially susceptible to the adverse effects of conventional antipsychotic medication. Lower dosages are more necessary for the elderly than for younger adults. Current evidence suggests that clozapine is the most effective atypical antipsychotic for neuroleptic-resistant patients. Risperidone, olanzapine, and quetiapine may also be effective in a subset of these patients.