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Converging evidence, including underexpression of 2′,3′-cyclic nucleotide 3′-phosphodiesterase (CNP) in the schizophrenic brain, suggests abnormal oligodendrocyte function in schizophrenia. Peirce et alArticle have identified a polymorphism that is associated with low CNP expression and show that the predicted low-expression allele is also associated with schizophrenia. The findings support the hypothesis that reduced CNP expression, and, more generally, oligodendrocyte function, is a primary etiological event in schizophrenia.
Vidal et alArticle detected a dynamic pattern of gray matter loss spreading across the medial hemispheric surface of the brain in childhood-onset schizophrenia. They scanned patients, controls, and medication-matched subjects using longitudinal magnetic resonance imaging over a 5-year period. With brain-mapping techniques, they created dynamic 3-dimensional maps localizing progressive limbic and frontal cortex deficits specific to schizophrenia. These findings shed light on the cognitive, metabolic, and functional changes in schizophrenia, revealing selective changes in the cortex.
Using microarray expression assays, Sequeira et alArticle identified SSAT, a gene involved in polyamine metabolism, as being differentially expressed in 3 cortical brain areas of suicide cases with and without major depression, as well as matched controls. These results were validated and further explored using complementary techniques. Genetic variation studies indicated that a variant in the promoter of this gene affects SSAT expression and is associated with suicide in the general population.
Cohen et alArticle investigated the relationship between socioeconomic status and response to antidepressants among older adults by conducting secondary analyses of data from 2 clinical trials testing effectiveness of combined pharmacologic and psychosocial treatments. Respondents residing in low-income census tracts were the least likely to respond to treatment and the most likely to report suicidal ideation.
In a large population-based cohort study, den Heijer et alArticle studied the relationship between hippocampal and amygdalar volumes using magnetic resonance imaging and the risk of developing dementia in the 6 years thereafter. They found that hippocampal and amygdalar atrophy predicted dementia even when people were cognitively intact and had no subjective complaints. This suggests that atrophy found with magnetic resonance imaging is an early predictor of dementia.
Age-related breakdown of the myelin sheath may result in progressive “disconnection” of neural networks and underlie age-related cognitive declines and the age risk factor for Alzheimer disease (AD). The apolipoprotein E genotype shifts the age at onset of AD and is the most influential AD risk factor after age itself. Bartzokis et alArticle report magnetic resonance imaging data showing that in later-myelinating regions like frontal lobes, the trajectory of age-related myelin breakdown in healthy older individuals is altered by apolipoprotein E alleles.
Brookes et alArticle investigated sources of heterogeneity in the genetic association between the dopamine transporter gene and attention-deficit/hyperactivity disorder. They identified a common haplotype associated with attention-deficit/hyperactivity disorder in 2 independent samples from England and Taiwan and a significant interaction between the risk haplotype and mothers' use of alcohol during the pregnancies of the affected offspring.
Favaro et alArticle found that several obstetrical complications, such as preeclampsia, diabetes mellitus, neonatal hyporeactivity, and cardiac problems, significantly increase the risk of developing anorexia nervosa. The number of perinatal complications was inversely correlated with onset age. Placental infarction, neonatal hyporeactivity, early eating difficulties, and a low birth weight for gestational age were significant predictors of bulimia nervosa. An impairment in neurodevelopment could be implicated in the pathogenesis of eating disorders.
Using positron emission tomography, Sekine et alArticle assessed the density of brain serotonin transporter (5-HTT) in abstinent methamphetamine abusers. The 5-HTT density in global regions was lower among abusers compared with control subjects. The decreased density in the orbitofrontal, temporal, and anterior cingulate areas was associated with elevated levels of aggression in methamphetamine abusers. Thus, abuse of methamphetamine may reduce 5-HTT density, leading to elevated aggression, even among those in a currently abstinent state.
Schwartz et alArticle performed a randomized clinical trial comparing interim methadone maintenance (methadone with emergency counseling only) to waiting-list control for heroin-dependent individuals enrolling on a waiting list for comprehensive methadone treatment. At the 4-month follow-up, participants assigned to interim methadone maintenance as compared with the control condition were significantly more likely to have entered comprehensive methadone treatment and were significantly less likely to use heroin and engage in illegal activity.
This Month in Archives of General Psychiatry. Arch Gen Psychiatry. 2006;63(1):12. doi:10.1001/archpsyc.63.1.12