The second-generation 'atypical' antipsychotics: similar improved efficacy but different neuroendocrine side effects

The neuroendocrine aspects of schizophrenia generally receive little attention. This is in marked contrast to depressive disorders, where neuroendocrine issues are central to discussions of pathophysiology and treatment. Although the nature of neuroendocrine dysfunction is less well characterized in schizophrenia than in major depression, a number of neuroendocrine abnormalities have been described. Hypercortisolemia has been extensively documented in patients with schizophrenia, particularly during acute exacerbations, with persistent hypercortisolemia being associated with ventricular enlargement and poor outcome. Similarly, abnormalities in thyroid function, the hypothalamo-pituitary-gonadal axis, growth hormone, prolactin, neurotensin, and other neuroendocrine parameters have also been described in schizophrenia. While the precise neuroendocrine profile of schizophrenia is incompletely characterized, the impact of antipsychotic medications employed in its treatment on various endocrine parameters is better understood. Different conventional and atypical antipsychotics variably contribute to hyperprolactinemia, insulin resistance, and other abnormalities. A critical overview of neuroendocrine abnormalities in schizophrenia is provided and the differential impact of different antipsychotics in contributing to neuroendocrine dysfunction is discussed.