Are biochemical markers for treatment-resistant schizophrenia state dependent or traits?

With increased understanding of antipsychotic drug treatment, the emphasis in research and clinical practice is shifting toward patients who do not respond or who respond only in part. At present the clinician can determine only after the fact whether a schizophrenic patient will respond to drug treatment. Antipsychotic drug response is seen as state dependent and may be determined by the biochemical condition of the patient. The authors have reviewed studies of biochemical measures and antipsychotic drug response. It appears that psychotic patients with elevated catecholamine release are likely to respond rapidly to neuroleptic treatment, whereas psychotic patients with lower cerebrospinal fluid (CSF) or plasma catecholamine levels are most likely to be treatment nonresponders. A dysregulation of the locus ceruleus may affect the dopamine system's responsivity to pharmacological interventions.