In This Issue

Male infants of women with schizophrenia or schizoaffective disorder, compared to male infants of healthy mothers, had larger volumes of gray matter, cerebrospinal fluid, lateral ventricles, and total intracranial matter at 1 month of age. Gilmore et al. (p. 1083) did not find differences in female infants. Neither sex had abnormalities in white matter tracts at 1 month or in ultrasound measurements of lateral ventricle width and head circumference at two points during pregnancy. The findings of large brain volumes in the male high-risk infants, however, expand the evidence for the neurodevelopmental hypothesis of schizophrenia, described by Dr. Randal Ross in an editorial (p. 1017). Two periods are considered critical: the perinatal period, when vulnerability is established, and adolescence/young adulthood, when conversion from vulnerability to psychosis occurs. This latter transition is the focus of a 10-year study by Dominguez et al. (p. 1075), who tracked schizophrenia-like features in a random sample of the general population ages 14–24 years. Negative and disorganized symptoms (e.g., reduced speech, illogical thoughts) were associated with male sex, younger age, and future onset of psychotic experiences (figure). In contrast, psychotic experiences were not related to subsequent onset of negative/disorganized symptoms but were associated with three environmental factors: trauma, urbanicity, and cannabis use. The combination of negative and psychotic features raised the risk for psychosisrelated impairment. The editorial by Dr. William Carpenter (p. 1013) links these findings to current discussions about dimensions of psychopathology, diagnostic classification, and care for persons with attenuated psychotic symptoms.

Variations in genes influencing histamine degradation influenced whether food additives had an adverse effect on symptoms of attention deficit hyperactivity disorder (ADHD) in 3- and 8/9-year-old children. Stevenson et al. (CME, p. 1108) discovered the interaction in a double-blind challenge trial that involved withdrawing food coloring additives from the children's diet and then adding them back. Genetic effects were also apparent in the 3-year-old children at baseline, when hyperactivity levels were related to one of the histamine-related polymorphisms and to one affecting dopamine neurotransmission. As noted by Dr. Bonnie Kaplan in an editorial (p. 1023), this research clarifies links between ADHD and diet by identifying possible mechanisms.