In a large population-based study of first-onset psychoses in the United Kingdom, Coid et al (SEE ARTICLE) demonstrated that the incidence rates of several psychotic syndromes were elevated for both first- and second-generation immigrants, but the exact magnitude of risk was conditional on ethnic group.
In a longitudinal study in monozygotic and dizygotic twin pairs discordant for schizophrenia, Brans et al (SEE ARTICLE) investigated whether genetic and/or environmental factors are associated with progressive brain volume changes. Both patients with schizophrenia and their unaffected co-twins showed significant decreases over time in whole-brain and frontal and temporal lobe volumes. Moreover, additive genetic influences on schizophrenia liability and progressive brain volume changes were found.
Arendt et al (SEE ARTICLE) investigated psychiatric disorders in first-degree family members of individuals experiencing cannabis-induced psychosis and compared them with the corresponding rates for individuals with schizophrenia spectrum disorders. With a few minor exceptions, the estimates were of similar magnitude. This indicates that cannabis-induced psychosis could be an early sign of schizophrenia rather than a distinct clinical entity.
Strigo et al (SEE ARTICLE) examined functional brain activation in young depressed adults during anticipation and receipt of painful heat stimulus and found increased emotional reactivity during pain anticipation and maladaptive emotional regulation during pain stimulation in recurrent major depressive disorder. These findings may shed a light on mechanisms underlying comorbidity of pain and depression.
Abnormalities in the metabolism of folate, vitamin B12, and homocysteine have been associated with depression, but it remains unclear if this is a truly causal relationship. Almeida et al (SEE ARTICLE) used the principles of mendelian randomization to show that lowering total homocysteine concentration by 1.4 µmol/L could potentially reduce the prevalence of depression in later life by 20%.
Polymorphisms of the serotonin transporter have been associated with mental illness and a heightened vulnerability to psychosocial stress. Comparing depressed with nondepressed stroke survivors, Kohen et al (SEE ARTICLE) found that subjects with the 5-HTTLPR s/s genotype or the STin2 VNTR 9/12 or 12/12 genotypes had more than 3-fold higher odds of depression following stroke.
Using functional brain imaging, Guyer et al (SEE ARTICLE) compared adolescents with and without social anxiety on neural response while anticipating social evaluation from smiling peers within a simulated Internet "chat room." Relative to healthy adolescents, anxious adolescents had greater amygdala and ventrolateral prefrontal cortex engagement when anticipating evaluation from negatively perceived peers.
Watson et al (SEE ARTICLE) found that boys with fragile X syndrome showed an increased response in the insula to direct eye gaze stimuli and a sensitization in the amygdala for repeated direct gaze stimuli when compared with typically developing and developmentally delayed adolescents.
Ladwig et al (SEE ARTICLE) found that among 211 cardiac patients treated with an implanted cardioverter-defibrillator, 147 patients had experienced a rapid, unexpected, and potentially traumatic onset of disease. Of these, 38 patients had sustained disease-related posttraumatic stress disorder symptoms. Despite no differences in major cardiac disease parameters, index patients experienced more than a 3-fold increase in mortality over a 5-year observation period.
In a nationwide register study, Kessing et al (SEE ARTICLE) found that persons who purchased lithium once had an increased rate of dementia compared with persons unexposed to lithium. For persons who continued taking lithium, the rate of dementia decreased to the same level as the rate for the general population. This association between the number of prescriptions with lithium and dementia was unique and different from the association between the number of prescriptions of anticonvulsants and dementia.
