The association between area-level residential instability and gray matter volume changes

Introduction

Area-level residential instability (ARI), an index of social fragmentation, has been shown to explain the association between urbanicity and psychosis. Urban upbringing has been shown to be associated with decreased gray matter volumes (GMV)s of brain regions corresponding to the right caudal middle frontal gyrus (CMFG) and rostral anterior cingulate cortex (rACC).

Objectives

We hypothesize that greater ARI will be associated with reduced right posterior CMFG and rACC GMVs.

Methods

Data were collected at baseline as part of the North American Prodrome Longitudinal Study. Counties where participants resided during childhood were geographically coded using the US Censuses to area-level factors. ARI was defined as the percentage of residents living in a different house five years ago. Generalized linear mixed models tested associations between ARI and GMVs.

Results

This study included 29 HC and 64 CHR-P individuals who were aged 12 to 24 years, had remained in their baseline residential area, and had magnetic resonance imaging scans. ARI was associated with reduced right CMFG (adjusted β = -0.258; 95% CI = -0.502 – -0.015) and right rACC volumes (adjusted β = -0.318; 95% CI = -0.612 – -0.023). The interaction terms (ARI X diagnostic group) in the prediction of both brain regions were not significant, indicating that the relationships between ARI and regional brain volumes held for both CHR-P and HCs.

Conclusions

Like urban upbringing, ARI may be an important social environmental characteristic that adversely impacts brain regions related to schizophrenia.

Disclosure

No significant relationships.

Alcohol confounds relationship between cannabis misuse and psychosis conversion in a high-risk sample

OBJECTIVE

Cannabis use has been examined as a predictor of psychosis in clinical high-risk (CHR) samples, but little is known about the impact of other substances on this relationship.

METHOD

Substance use was assessed in a large sample of CHR participants (N = 370, mean age = 18.3) enrolled in the multisite North American Prodrome Longitudinal Study Phase 1 project. Three hundred and forty-one participants with cannabis use data were divided into groups: No Use (NU, N = 211); Cannabis Use without impairment (CU, N = 63); Cannabis Abuse/Dependence (CA/CD, N = 67). Participants (N = 283) were followed for ≥2 years to determine psychosis conversion.

RESULTS

Alcohol (45.3%) and cannabis (38.1%) were the most common substances. Cannabis use groups did not differ on baseline attenuated positive symptoms. Seventy-nine of 283 participants with cannabis and follow-up data converted to psychosis. Survival analysis revealed significant differences between conversion rates in the CA/CD group compared with the No Use (P = 0.031) and CU group (P = 0.027). CA/CD also significantly predicted psychosis in a regression analysis, but adjusting for alcohol use weakened this relationship.

CONCLUSION

The cannabis misuse and psychosis association was confounded by alcohol use. Non-impairing cannabis use was not related to psychosis. Results highlight the need to control for other substance use, so as to not overstate the cannabis/psychosis connection.

Is adult attention deficit hyperactivity disorder a valid diagnosis in the presence of high IQ?

BACKGROUND

Because the diagnosis of attention deficit hyperactivity disorder (ADHD) in higher education settings is rapidly becoming a contentious issue, particularly among patients with high IQs, we sought to assess the validity of diagnosing ADHD in high-IQ adults and to further characterize the clinical features associated with their ADHD.

METHOD

We operationalized high IQ as having a full-scale IQ120. We identified 53 adults with a high IQ who did not have ADHD and 64 adults with a high IQ who met diagnostic criteria for ADHD. Groups did not differ on IQ, socio-economic status or gender.

RESULTS

High-IQ adults with ADHD reported a lower quality of life, had poorer familial and occupational functioning, and had more functional impairments, including more speeding tickets, accidents and arrests. Major depressive disorder, obsessive-compulsive disorder and generalized anxiety disorder diagnoses were higher in high-IQ adults with ADHD. All other psychiatric co-morbidities, including antisocial personality disorder and substance abuse, did not differ between the two high-IQ groups. ADHD was more prevalent in first-degree relatives of adults with ADHD relative to controls.

CONCLUSIONS

Our data suggest that adults with ADHD and a high IQ display patterns of functional impairments, familiality and psychiatric co-morbidities that parallel those found in the average-IQ adult ADHD population.

Housing placement and subsequent days homeless among formerly homeless adults with mental illness

OBJECTIVE

The study examined the influence of group or individual housing placement and consumer characteristics on the number of days subsequently homeless among formerly homeless mentally ill persons.

METHODS

A total of 303 homeless shelter residents with severe mental illness were screened for dangerousness, 118 were randomly assigned to either independent apartment or staffed group living sites, and 110 were followed for 18 months. Study participants' sociodemographic characteristics, diagnosis, and residential preferences and the residential recommendations made by clinicians were measured at baseline.

RESULTS

Overall, 76 percent of the study participants were housed at the end of the 18-month follow-up period, although 27 percent had experienced at least one episode of homelessness during the period. The number of days homeless was greater for individuals assigned to independent apartments than for those placed in staffed group homes, but only for members of minority groups. Substance abuse was the strongest individual-level predictor of days homeless. Individuals whom clinicians identified as needing group living experienced more days homeless, irrespective of the type of housing they received. Consumers who stated a strong preference for independent living had more days homeless than those who were amenable to staffed group homes.

CONCLUSIONS

Although consumers more frequently prefer independent living, placement in staffed group housing resulted in somewhat fewer days homeless for some groups of consumers. Further experience of homelessness by formerly homeless mentally ill individuals may be reduced by providing effective substance abuse treatment and by paying special attention to consumers identified by clinicians to be at particular risk for housing loss.

Effectiveness and tolerability of tomoxetine in adults with attention deficit hyperactivity disorder

OBJECTIVE

The authors assessed the experimental noradrenergic compound tomoxetine as an alternative treatment for adult attention deficit hyperactivity disorder (ADHD).

METHOD

They conducted a double-blind, placebo-controlled, crossover study of tomoxetine in 22 adults with well-characterized ADHD.

RESULTS

Treatment with tomoxetine at an average oral dose of 76 mg/day was well tolerated. Drug-specific improvement in ADHD symptom was highly significant overall and sufficiently robust to be detectable in a parallel-groups comparison restricted to the first 3 weeks of the protocol. Eleven of 21 patients showed improvement after receiving tomoxetine, compared with only two of 21 patients who improved after receiving placebo. Significant tomoxetine-associated improvement was noted on neuropsychological measures of inhibitory capacity from Stroop tests.

CONCLUSIONS

This preliminary study showed that tomoxetine was effective in treating adult ADHD and was well tolerated. These promising results provide support for further studies of tomoxetine over an extended period of treatment.

Regulation of nerve growth factor mRNA by interleukin-1 in rat hippocampal astrocytes is mediated by NFkappaB

Cytokines such as interleukin-1beta (Il-1) are produced in the brain during development and during inflammatory processes that result from lesions or disease. One function of Il-1 in the brain appears to be the stimulation of astrocytes to proliferate and produce a variety of cytokines and trophic factors, including nerve growth factor. The mechanisms by which Il-1 exerts its actions on astrocytes remain poorly defined. We present evidence that this cytokine elicits activation of the NFkappaB transcription factor and that this transcription factor mediates effects of Il-1 on nerve growth factor mRNA expression. Elucidation of the processes by which cytokines activate astrocytes and influence trophic factor expression may provide insight into mechanisms governing inflammatory processes within the central nervous system.

The membrane composition of coated pits, microvilli, endosomes, and lysosomes is distinctive in the rat kidney proximal tubule cell

The distribution of a number of membrane proteins on plasmalemmal microdomains (microvilli, coated pits) and in endosomes and lysosomes of the proximal tubule epithelial cell was determined in normal rat kidneys by immunofluorescence and immunoelectron microscopy. Two major brush border proteins, 130 and 94 kD, and gamma-glutamyl transpeptidase were detected on the membranes of the microvilli but were not found on membranes of coated pits. Gp330, the Heymann nephritis antigen, and clathrin were localized in coated pits. The lysosomal membrane glycoprotein, lgp120 (Lewis, V., S. A. Green, M. Marsh, P. Vihko, A. Helenius, and I. Mellman, 1985, J. Cell Biol., 100: 1839-1847) was restricted to lysosomes where it co-localized with beta-glucuronidase. Endosomes, identified by preloading with HRP injected 5-15 min before rats were killed, did not contain detectable amounts of any antigen tested. The distribution of the same proteins was also determined in rats given sodium maleate, which is known to slow or reduce protein absorption by the proximal tubule and to cause vacuolation of the endocytic apparatus. After maleate treatment the distribution of microvillar and lysosomal markers was unchanged, but the coated pit markers were redistributed--gp330 was concentrated in newly formed apical vacuoles, and clathrin was diffusely distributed in the apical cytoplasm or on apical coated vesicles. These findings indicate that the membrane composition of microvilli, coated pits, endosomes, and lysosomes is distinctive in the proximal tubule cell; and that gp330, unlike other known coated pit membrane components, is not transferred to endosomes during endocytosis. After maleate treatment, the coated pits lose their clathrin coats, and the corresponding membrane is internalized.