Mental disorders as risk factors for later substance dependence: estimates of optimal prevention and treatment benefits.

BACKGROUND: Although mental disorders have been shown to predict subsequent substance disorders, it is not known whether substance disorders could be cost-effectively prevented by large-scale interventions aimed at prior mental disorders. Although experimental intervention is the only way to resolve this uncertainty, a logically prior question is whether the associations of mental disorders with subsequent substance disorders are strong enough to justify mounting such an intervention. We investigated this question in this study using simulations to estimate the number of substance disorders that might be prevented under several hypothetical intervention scenarios focused on mental disorders. METHOD: Data came from the National Comorbidity Survey Replication (NCS-R), a nationally representative US household survey that retrospectively assessed lifetime history and age of onset of DSM-IV mental and substance disorders. Survival analysis using retrospective age-of-onset reports was used to estimate associations of mental disorders with subsequent substance dependence. Simulations based on the models estimated effect sizes in several hypothetical intervention scenarios. RESULTS: Although successful intervention aimed at mental disorders might prevent some proportion of substance dependence, the number of cases of mental disorder that would have to be treated to prevent a single case of substance dependence is estimated to be so high that this would not be a cost-effective way to prevent substance dependence (in the range 76-177 for anxiety-mood disorders and 40-47 for externalizing disorders). CONCLUSIONS: Treatment of prior mental disorders would not be a cost-effective way to prevent substance dependence. However, prevention of substance dependence might be considered an important secondary outcome of interventions for early-onset mental disorders.

Molecular analysis of the regulation of muscarinic receptor expression and function.

We have investigated the molecular mechanisms involved in the regulation of muscarinic acetylcholine receptor gene expression and localization and generated knockout mice to study the role of the M1 muscarinic receptor in vivo. We have used the MDCK cell system to demonstrate that different subtypes of mAChR can be targeted to different regions of polarized cells. We have also examined the developmental regulation of mAChR expression in the chick retina. Early in development, the M4 receptor is the predominant mAChR while the levels of the M2 and M3 receptors increase later in development. The level of M2 receptor is also initially very low in retinal cultures and undergoes a dramatic increase over several days in vitro. The level of M2 receptor can be increased by a potentially novel, developmentally regulated, secreted factor produced by retinal cells. The promoter for the chick M2 receptor gene has been isolated and shown to contain a site for GATA-family transcription factors which is required for high level cardiac expression. The M2 promoter also contains sites which mediate induction of transcription in neural cells by neurally active cytokines. We have generated knockout mice lacking the M1 receptor and shown that these mice do not exhibit pilocarpine-induced seizures and muscarinic agonist-induced suppression of the M-current potassium channel in sympathetic neurons.

Restless Legs Syndrome and the five-factor model of personality: results from a community sample.

OBJECTIVE: To examine personality characteristics as potential mediators of the association between Restless Legs Syndrome (RLS) and psychiatric disorders. METHOD: Revised NEO Personality Inventory traits are compared in respondents with (n=42) versus without (n=982) a diagnosis of RLS in a general population sample. RESULTS: RLS was associated with higher neuroticism after adjusting for potential confounders, including current psychopathology. Further analysis showed that the association between RLS and neuroticism contributes to, but does not fully explain, the relationship between RLS and either panic disorder or major depression. CONCLUSIONS: Neuroticism may mediate part of the relationship between RLS and depression or panic, but the mechanisms of these associations need further exploration.

Does the 'gateway' matter? Associations between the order of drug use initiation and the development of drug dependence in the National Comorbidity Study Replication.

BACKGROUND: The 'gateway' pattern of drug initiation describes a normative sequence, beginning with alcohol and tobacco use, followed by cannabis, then other illicit drugs. Previous work has suggested that 'violations' of this sequence may be predictors of later problems but other determinants were not considered. We have examined the role of pre-existing mental disorders and sociodemographics in explaining the predictive effects of violations using data from the US National Comorbidity Survey Replication (NCS-R). METHOD: The NCS-R is a nationally representative face-to-face household survey of 9282 English-speaking respondents aged 18 years and older that used the World Health Organization (WHO) Composite International Diagnostic Interview (CIDI) to assess DSM-IV mental and substance disorders. Drug initiation was estimated using retrospective age-of-onset reports and 'violations' defined as inconsistent with the normative initiation order. Predictors of violations were examined using multivariable logistic regressions. Discrete-time survival analysis was used to see whether violations predicted progression to dependence. RESULTS: Gateway violations were largely unrelated to later dependence risk, with the exception of small increases in risk of alcohol and other illicit drug dependence for those who initiated use of other illicit drugs before cannabis. Early-onset internalizing disorders were predictors of gateway violations, and both internalizing and externalizing disorders increased the risks of dependence among users of all drugs. CONCLUSIONS: Drug use initiation follows a strong normative pattern, deviations from which are not strongly predictive of later problems. By contrast, adolescents who have already developed mental health problems are at risk for deviations from the normative sequence of drug initiation and for the development of dependence.

Prevalence and incidence of depressive disorder: the Baltimore ECA follow-up, 1981-2004.

OBJECTIVE: To describe trends in prevalence and incidence of depressive disorder in a cohort from Eastern Baltimore. METHOD: Twenty-three-year-old longitudinal cohort, the Baltimore Epidemiologic Catchment Area Follow-up. Participants were selected probabilistically from the household population in 1981, and interviewed in 1981, 1993, and 2004. Diagnoses were made via the Diagnostic Interview Schedule according to successive editions of the American Psychiatric Association Diagnostic and Statistical Manual. RESULTS: Older age, lower education, non-White race, and cognitive impairment are independent predictors of attrition due to death and loss of contact, but depressive disorder is not related to attrition. Prevalence rates rise for females between 1981, 1993, and 2004. Incidence rates in the period 1993-2004 are lower than the period 1981-1993, suggesting the rise in prevalence is due to increasing chronicity. CONCLUSION: There has been a rise in the prevalence of depression in the prior quarter century among middle-aged females.

How migraines impact cognitive function: findings from the Baltimore ECA.

OBJECTIVE: To examine the cross-sectional and longitudinal relationship between migraine headaches and cognitive functioning. METHODS: The data were from Waves III (1993 through 1996) and IV (2004 through 2005) of the Baltimore Epidemiologic Catchment Area Study. Migraine headaches were diagnosed according to modified criteria of the International Headache Society. Scores on the immediate and delayed recall tests and the Mini-Mental State Examination (MMSE) were compared for migraineurs (n = 204) vs nonmigraineurs (n = 1,244). The longitudinal association between migraine and cognitive changes was assessed by generalized estimating equations. RESULTS: Migraineurs scored lower on tests of immediate and delayed memory at baseline, but declined by less over time than nonmigraineurs. These associations were specific to migraineurs with aura, who declined by 1.26 (p < 0.01) and 1.47 (p < 0.01) words less on the immediate and delayed recall tests over the 12 years of follow-up. The effects of migraine, specifically with aura, on the MMSE were restricted to those older than 50 years. Among those younger than 50 years, migraineurs with aura declined at the same rate on the MMSE as nonmigraineurs. However, among those older than 50 years, migraineurs with aura declined by 0.99 points (p < 0.01) less over the follow-up. CONCLUSIONS: Migraineurs, specifically those with aura, exhibited less decline on cognitive tests over time vs nonmigraineurs. For the Mini-Mental State Examination, these effects were only apparent among those who were older than 50 years.

The gluten connection: the association between schizophrenia and celiac disease.

OBJECTIVE: Schizophrenia affects roughly 1% of the population and is considered one of the top 10 causes of disability worldwide. Given the immense cost to society, successful treatment options are imperative. Based on initial findings, gluten withdrawal may serve as a safe and economical alternative for the reduction of symptoms in a subset of patients. METHOD: A review of the literature relevant to the association between schizophrenia and celiac disease (gluten intolerance) was conducted. RESULTS: A drastic reduction, if not full remission, of schizophrenic symptoms after initiation of gluten withdrawal has been noted in a variety of studies. However, this occurs only in a subset of schizophrenic patients. CONCLUSION: Large-scale epidemiological studies and clinical trials are needed to confirm the association between gluten and schizophrenia, and address the underlying mechanisms by which this association occurs.