The study confirms that D(2) occupancy is an important mediator of response and side effects in antipsychotic treatment. The data are consistent with a "target and trigger" hypothesis of antipsychotic action, i.e., that the D(2) receptor specificity of antipsychotics permits them to target discrete neurons and that their antagonist properties trigger within those neurons intracellular changes that ultimately beget antipsychotic response. While limited to haloperidol, the relationship between D(2) occupancy and side effects in this study helps explain many of the observed clinical differences between typical and atypical antipsychotics.
Magnetic resonance imaging (MRI) was used to study in vivo the brains of 49 patients with chronic alcoholism, 3 to 4 weeks post-withdrawal, and 43 normal healthy controls, all right-handed male veterans between the ages of 23 and 70 years. MRI scans were analyzed using a semi-automated procedure, which allowed the subcortical regions to be segmented into cerebrospinal fluid (CSF) and brain tissue and the cortical regions to be segmented into CSF, gray matter, and white matter. An age regression model was used to examine the effects of alcohol on brain structure, over and above that expected from the normal aging process. The alcoholics exhibited decreased tissue and increased CSF after correcting for aging. In the cortex, there was significant loss of both gray matter and white matter volume. In this sample of alcoholics, no particular cortical region was preferentially affected or spared. Furthermore, brain tissue volume loss increased with advanced age in the alcoholics. In this group of alcoholics there was no relationship between length of illness and age, i.e., the younger alcoholics had as heavy alcohol use histories as did the older alcoholics. Thus, the increased brain tissue loss with advanced age is interpreted as evidence for age-related increase in brain vulnerability to chronic alcohol abuse.
A significant treatment difference in the conversion-to-psychosis rate was not demonstrated. However, these results may be influenced by low power. The nearly significant differences suggest that olanzapine might reduce the conversion rate and delay onset of psychosis. Olanzapine was efficacious for positive prodromal symptoms but induced weight gain. Further treatment research in this phase of illness is warranted.
As expected on the basis of previous studies, both olanzapine and haloperidol were effective in the acute reduction of psychopathological symptoms in this group of patients with first-episode psychosis. However, olanzapine had several relative advantages in therapeutic response. Although the nature of adverse events differed between the two agents, retention in the study was greater with olanzapine. Retention in treatment is important in this patient population, given their risk of relapse. Longer-term results are needed to determine whether treatment with atypical antipsychotics results in superior outcomes for a first episode of schizophrenia.
Outcome from FEP may be more favorable than previously reported, and treatment and methodological variables may be important contributors to outcome. Significant heterogeneity in definitions and methodology limited the comparison and pooling of data. A multi-dimensional, globally used definition of outcome is required for future research.
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