Increased academic stress is associated with decreased plasma BDNF in Chilean college students.

Introduction: Academic stress (AS) is a prevalent challenge faced by university students, potentially affecting molecular indicators such as brain-derived neurotrophic factor (BDNF) and global DNA methylation (G-DNA-M). These indicators could illuminate the physiological ramifications of academic stress. Study Design and Methods: This research followed a quantitative, non-experimental, longitudinal panel design spanning two academic semesters, observing phenomena in their natural context. Students from the Medical Technology program at Universidad de Concepción, Chile were involved, with assessments at the beginning and during heightened academic stress periods. Sample: Of the total participants, 63.0% were females, with an average age of 21.14 years at baseline, and 36.92% were males, averaging 21.36 years. By the study's conclusion, female participants averaged 21.95 years, and males 22.13 years. Results: Significant differences were observed between initial and final assessments for the SISCO-II Inventory of Academic Stress and Beck Depression Inventory-II, notably in stressor scores, and physical, and psychological reactions. Gender differences emerged in the final physical and psychological reactions. No significant changes were detected between the two assessments in plasma BDNF or G-DNA-M values. A refined predictive model showcased that, on average, there was a 3.56% decrease in females' plasma BDNF at the final assessment and a 17.14% decrease in males. In the sample, the G-DNA-M percentage at the final assessment increased by 15.06% from the baseline for females and 18.96% for males. Conclusions: The study underscores the physiological impact of academic stress on university students, evidenced by changes in markers like BDNF and G-DNA-M. These findings offer an in-depth understanding of the intricate mechanisms regulating academic stress responses and highlight the need for interventions tailored to mitigate its physiological and psychological effects.

Interaction of Val66Met BDNF and 5-HTTLPR polymorphisms with prevalence of post-earthquake 27-F PTSD in Chilean population.

Post-traumatic stress (PTSD) disorder is a mental health condition that can occur after experiencing or witnessing a traumatic event. The 27-F earthquake that struck Chile in 2010 was one such event that had a significant impact on the mental health of the population. A study was conducted to investigate the prevalence of PTSD and its associated factors among survivors of this earthquake. The study was a longitudinal design, involving a sample of 913 patients aged 18 to 75 years who attended 10 Primary Care Centers in Concepción, Chile. The Composite International Diagnostic Interview (CIDI) was used to assess both depressive episodes (DE) and PTSD before and after the earthquake. The study also involved genotyping studies using saliva samples from the participants, specifically focusing on the Val66Met and 5-HTTLPR polymorphisms. Statistical analysis was performed to examine the association between different variables and the presence of PTSD. These variables included demographic factors, family history of psychiatric disorders, DE, childhood maltreatment experiences, and critical traumatic events related to the earthquake. The results showed that the incidence of post-earthquake PTSD was 11.06%. No significant differences were found between the groups of participants who developed post-earthquake PTSD regarding the Val66Met or 5-HTTLPR polymorphisms. However, a significant association was found between the concomitant diagnosis of DE and the development of post-earthquake PTSD. The presence of DE doubled the risk of developing post-earthquake PTSD. The number of traumatic events experienced also had a statistically significant association with an increased risk of developing post-earthquake PTSD. The study's limitations include the potential interference of different DE subtypes, the complexity of quantifying the degree of earthquake exposure experienced by each individual, and events entailing social disruption, such as looting, that can profoundly influence distress. In conclusion, the study found that PTSD following the 27-F earthquake in Chile was associated with a concomitant diagnosis of DE and the number of traumatic events experienced. The study did not find a significant association between PTSD and the Val66Met or 5-HTTLPR polymorphisms. The researchers recommend that mental health professionals should prioritize the detection and treatment of concomitant depressive episodes and exposure to critical traumatic events in survivors of disasters. They also suggest that further research is needed to better understand the relationship between genetic factors and post-disaster PTSD.

Adaptación y validación del Test de Alfabetización en Salud Mental Canadiense (tmhhscg) en estudiantes chilenos / Adaptation and Validation of the Canadian Mental Health Literacy Test (tmhhscg) in Chilean Students / Adaptação e validação do Teste de Alfabetização em Saúde Mental Canadense (tmhhscg) em estudantes chilenos

la alfabetización en salud mental (ASM) se define como el conocimiento y las creencias sobre los trastornos mentales que ayudan a su reconocimiento, manejo y prevención. Se buscó traducir, adaptar y validar el instrumento canadiense Test Mental Health & High School Curriculum Guide (TMHHSCG) en estudiantes de secundaria y universitarios chilenos. Materiales y métodos: estudio de diseño instrumental en adolescentes (n = 454) y jóvenes (n = 434). Se llevó a cabo un proceso de adaptación compuesto por traducción y retrotraducción, y entrevistas cognitivas y de validación a través de análisis factorial para la validez de criterio y de constructo, análisis de validez convergente y divergente y análisis de invarianza factorial. Resultados: las dimensiones del TMHHSCGCL que conforman la ASM (conocimiento sobre trastornos mentales y salud mental, estigma hacia las personas con trastorno mental y búsqueda de ayuda) cumplieron con el requisito de un factor superior o igual 0.3. Hubo niveles de correlación moderada, positiva y significativa entre las dimensiones del test y entre este y las tres escalas utilizadas para probar la validez de criterio, tuvo buena consistencia interna y validez de constructo, convergente y discriminante. El análisis de invarianza de medición comparó modelos de manera progresiva y mostró una buena invarianza factorial. Conclusión: el TMHHSCGCL muestra adecuadas propiedades psicométricas que incorpora todos los componentes de la ASM. Ello permitirá medir el nivel de ASM para desarrollar intervenciones de prevención y promoción en salud mental en estudiantes de educación secundaria y universitaria.

Mental Health Literacy (mhl) is defined as knowledge and beliefs about mental disorders that aid in their recognition, management and prevention. We sought to translate, adapt and validate the Canadian instrument Test Mental Health & High School Curriculum Guide (tmhhscg) in Chilean high school and university students. Materials and methods: Instrumental design study in adolescents (n = 454) and young adults (n = 434). An adaptation process consisting of translation and back-translation, and cognitive and validation interviews was carried out by means of factor analysis for criterion and construct validity, convergent and divergent validity analysis, and factorial invariance analysis. Results: The dimensions of the tmhhscg-cl that compose the mhl (knowledge about mental disorders and mental health, stigma towards people with mental disorders, and help-seeking) met the requirement of a factor greater than or equal to 0.3. There were moderate, positive and significant levels of correlation between the test dimensions and between the test and the three scales used to test criterion validity, had good internal consistency and construct, convergent and discriminant validity. The measurement invariance analysis compared the models progressively and showed good factorial invariance. Conclusion: The tmhhscg-cl shows adequate psychometric properties incorporating all the components of mhl. This will allow measuring the level of mhl, in order to develop prevention and promotion interventions in mental health in high school and university students.

a alfabetização em saúde mental (asm) é definida como o conhecimento e as crenças sobre perturbações mentais que ajudam no seu reconhecimento, gestão e prevenção. Procurámos traduzir, adaptar e validar o instrumento canadiano Test Mental Health & High School Curriculum Guide (tmhhscg) em estudantes chilenos do ensino secundário e universitários. Materiais e métodos: estudo de concepção instrumental em adolescentes (n = 454) e jovens adultos (n = 434). Foi realizado um processo de adapta-ção que consiste na tradução e retrotradução, entrevistas cognitivas e validação através da análise de fatores para critérios e construção de validade, análise de validade convergente e divergente, e análise de invariância fatorial. Resultados: as dimensões tmhhscg-cl que compreendem o asm (conhecimento sobre perturbações mentais e saúde mental, estigma para pessoas com perturbações mentais, e procura de ajuda) cumpriram a exigência de um fator maior ou igual a 0,3. Havia níveis moderados, positivos e significativos de correlação entre as dimensões do teste e entre o teste e as três escalas utilizadas para testar a validade dos critérios, boa consistência interna e validade construtiva, convergente e discrimi-nante. A análise da invariância das medições comparou progressivamente os modelos e mostrou uma boa invariância fatorial. Conclusão: o tmhhscg-cl mostra propriedades psicométricas adequadas incorpo-rando todos os componentes da asm. Isto permitir-nos-á medir o nível de asm a fim de desenvolver inter-venções de prevenção e promoção da saúde mental em estudantes do ensino secundário e universitário.

Effect of sensorimotor rehabilitation based on an immersive virtual reality model on mental health.

The aim of this study was to determine the immersive virtual reality-based sensorimotor rehabilitation (IVR-SRB) effect on mental health (global mental health, depression, anxiety and well-being) in older adults. METHODS: This study was experimental, with a sample of 111 older adults (control-experimental), considering an application of IVR-SRB in four different virtual settings with exteroceptive synchronization, proprioceptive and vestibular stimuli, for 6 weeks. OUTCOME VARIABLES: symptoms associated with depression and anxiety; positive mental health (psychological well-being). A descriptive and inferential approach was used to analyze the data, and the ANCOVA test was used to compare the post-intervention groups, controlled by the baseline; In case of baseline moderation, a linear regression model was applied to identify the level of moderation and a region of significance analysis. RESULTS: An IVR-SRB positive net effect was found in the reduction of symptoms of global mental health (p < 0.0001) and depression (p < 0.0001), without baseline moderation. The anxiety scores showed moderation at the beginning (p < 0.0001; b = -0.53), identifying that the greater the presence of anxiety symptoms, the greater the effect of IVR-SRB in reducing these symptoms; its effect is present from scores of 2.9 (Goldberg-12). There were no changes in well-being. CONCLUSION: IVR-SRB is recognized as a great intervention tool among elderly population, showing its multidimensional approach capacity, properly responding to the reduction of symptoms associated with mental disorders.

Etifoxine is non-inferior than clonazepam for reduction of anxiety symptoms in the treatment of anxiety disorders: a randomized, double blind, non-inferiority trial.

OBJECTIVE: To determine whether etifoxine, a non-benzodiazepine drug of the benzoxazine family, is non-inferior compared with clonazepam in the treatment of anxiety disorders. METHOD: A randomized controlled double blind trial with parallel groups was conducted. A total of 179 volunteer patients with a diagnosis of anxiety disorder (DSM-IV), between 18 and 64 years of age, participated in this study. The experimental group received 150 mg/day of etifoxine and the control 1 mg/day of clonazepam, both in three daily doses for 12 weeks. This treatment was completed by 87 participants, and 70 were available for follow-up at 24 weeks from start of treatment. The primary objective was a non-inferiority comparison between etifoxine and clonazepam in the decrease of anxiety symptoms (HAM-A) at 12 weeks of treatment. Secondary outcomes included the evaluation of medication side effects (UKU), anxiety symptoms at 24 weeks of treatment, and clinical improvement (CGI). Data analysis included multiple imputation of missing data. The effect of etifoxine on the HAM-A, UKU, and CGI was evaluated with the intention of treatment, and a sensitivity analysis of the results was conducted. Non-inferiority would be declared by a standardized mean difference (SMD) between clonazepam and etifoxine not superior to 0.31 in favour of clonazepam. RESULTS: Using imputed data, etifoxine shows non-inferiority to clonazepam on the reduction of anxiety symptoms at the 12-week (SMD = 0.407; 95% CI, 0.069, 0.746) and 24-week follow-ups (SMD = 0.484; 95% CI, 0.163, 0.806) and presented fewer side effects (SMD = 0.58; 95% CI, 0.287, 0.889). LOCF analysis shows that etifoxine is non-inferior to clonazepam on reduction of anxiety symptoms and adverse symptoms even when no change was assigned as result to participant whom withdrew. Non-inferiority could be declared for clinical improvement (SMD = 0.326; 95% CI, - 0.20, 0.858). CONCLUSION: Etifoxine was non-inferior to clonazepam on reduction of anxiety symptoms, adverse effects, and clinical improvement.

Gabapentin Inhibits Multiple Steps in the Amyloid Beta Toxicity Cascade.

Oligomeric ß-amyloid peptide (Aß) is one of the main neurotoxic agents of Alzheimer's disease (AD). Oligomers associate to neuronal membranes, forming "pore-like" structures that cause intracellular calcium and neurotransmitter dyshomeostasis, leading to synaptic failure and death. Through molecular screening targeting the C terminal region of Aß, a region involved in the toxic properties of the peptide, we detected an FDA approved compound, gabapentin (GBP), with neuroprotective effects against Aß toxicity. At micromolar concentrations, GBP antagonized peptide aggregation over time and reduced the Aß absorbance plateau to 28% of control. In addition, GBP decreased Aß association to membranes by almost half, and the effects of Aß on intracellular calcium in hippocampal neurons were antagonized without causing effects on its own. Finally, we found that GBP was able to block the synaptotoxicity induced by Aß in hippocampal neurons, increasing post-synaptic currents from 1.7 ± 0.9 to 4.2 ± 0.7 fC and mean relative fluorescence intensity values of SV2, a synaptic protein, from 0.7 ± 0.09 to 1.00 ± 0.08. The results show that GBP can interfere with Aß-induced toxicity by blocking multiple steps, resulting in neuroprotection, which justifies advancing toward additional animal and human studies.

Assessing the relationship between psychosocial stressors and psychiatric resilience among Chilean disaster survivors.

BACKGROUND: According to the stress inoculation hypothesis, successfully navigating life stressors may improve one's ability to cope with subsequent stressors, thereby increasing psychiatric resilience. AIMS: Among individuals with no baseline history of post-traumatic stress disorder (PTSD) and/or major depressive disorder (MDD), to determine whether a history of a stressful life event protected participants against the development of PTSD and/or MDD after a natural disaster. METHOD: Analyses utilised data from a multiwave, prospective cohort study of adult Chilean primary care attendees (years 2003-2011; n = 1160). At baseline, participants completed the Composite International Diagnostic Interview (CIDI), a comprehensive psychiatric diagnostic instrument, and the List of Threatening Experiences, a 12-item questionnaire that measures major stressful life events. During the study (2010), the sixth most powerful earthquake on record struck Chile. One year later (2011), the CIDI was re-administered to assess post-disaster PTSD and/or MDD. RESULTS: Marginal structural logistic regressions indicated that for every one-unit increase in the number of pre-disaster stressors, the odds of developing post-disaster PTSD or MDD increased (OR = 1.21, 95% CI 1.08-1.37, and OR = 1.16, 95% CI 1.06-1.27 respectively). When categorising pre-disaster stressors, individuals with four or more stressors (compared with no stressors) had higher odds of developing post-disaster PTSD (OR = 2.77, 95% CI 1.52-5.04), and a dose-response relationship between pre-disaster stressors and post-disaster MDD was found. CONCLUSIONS: In contrast to the stress inoculation hypothesis, results indicated that experiencing multiple stressors increased the vulnerability to developing PTSD and/or MDD after a natural disaster. Increased knowledge regarding the individual variations of these disorders is essential to inform targeted mental health interventions after a natural disaster, especially in under-studied populations.

Plan nacional de salud mental. Reflexiones en torno a la implementación del modelo de psiquiatría comunitaria en Chile / Analysis of the new Chilean mental health care plan

During the sixties, the psychiatric care models evolved to a community care model, as a consequence of the asylum model failure. This new model assumes that psychosocial issues have a role, along with biological factors, in the development of mental diseases. In 2017 the National Mental health plan was created, based on this new model. It aimed to correct the flaws of the previous plan. We herein review this new plan, based on previous and international experiences. We also analyze the implementation of a community model of mental health care. The implementation of such a model without the support of the state and overlooking importance of mental health care, is extremely difficult.

Porcentaje de peso perdido y su recuperación en pacientes bariátricos: un análisis desde la perspectiva temporal / Percentage of total weight loss and weight regain in bariatric patients: a time perspective analysis

RESUMEN La perspectiva temporal se ha asociado a hábitos relacionados con salud. Específicamente, el futuro ha sido asociado a cambios en el estilo de vida como la incorporación de ejercicio físico. En cambio, el presente hedonista se ha asociado a la perdida sub-óptima de peso en pacientes bariátricos. Objetivo: Evaluar la relación entre las variables de la perspectiva temporal y el porcentaje de peso total perdido; su mantención o re-ganancia desde el nadir, en pacientes bariátricos. Material y métodos: Se aplicó a 97 pacientes bariátricos el Inventario de la Perspectiva Temporal de Zimbardo y Boyd, y un cuestionario de estilo de vida construido para esta investigación. Resultados: Un mayor porcentaje de peso total perdido se asoció significativamente a futuro (r= 0,221; p<0,05) y desviación del perfil temporal negativo (r= 0,324; p<0,05). La pérdida de peso insuficiente estuvo asociada al presente fatalista (t= −2,16; p= 0,033) y desviación del perfil temporal balanceado (t= −2,81; p= 0,006). La re-ganancia del %PTP se asoció significativamente a la desviación del perfil temporal balanceado (t= −2,09; p= 0,045) y al consumo de dulces (X2= 13,42; p= 0,009). Conclusiones: Una mayor desviación de la perspectiva temporal balanceada y un mayor consumo de dulces se asociaron a una pérdida de peso insuficiente y a la recuperación desde el nadir.

ABSTRACT Background: A person's perspective of time has been associated with health-related habits. Specifically, future has been associated with changes in lifestyle as well the incorporation of physical exercise. In contrast, current hedonism is associated with sub-optimal weight loss in bariatric patients. Aim: To evaluate the relationship between seven variables of a time perspective and percentage of total weight loss; maintenance or weight regain among bariatric patients. Material and Methods: A sample of 97 bariatric patients answered the Inventory of Temporary Orientation and lifestyle questionnaires. Results: A greater percentage of total weight loss was significantly associated with future (r= 0.221; p<0.05) and deviations from negative time profile (r= 0.324; p<0.05). Insufficient weight loss was associated with a fatalistic present (t= −2.16, p= 0.033) and deviations from a balanced time perspective (t= −2.81; p= 0.006). Regaining weight was significantly associated to deviations from a balanced time perspective (t= −2.09; p=0.045) and consumption of sweets (X2= 13.42; p= 0.009). Conclusions: Deviations from a balanced time perspective and consumption of sweets are associated with sub-optimal weight loss and regaining weight.

Predictores psicológicos de la re-ganancia del peso en pacientes bariátricos / Psychological predictors of the regain of weight in bariatric patients

Resumen La cirugía bariátrica permite una pérdida ponderal significativa y acelerada en el corto plazo. La re-ganancia del peso se observa entre el 15 al 30% de los pacientes. Los factores psicológicos explicarían en mayor medida la recuperación del peso en pacientes bariátricos. El objetivo del presente estudio fue evaluar la capacidad predictiva de las variables "locus de control del peso", "perspectiva temporal" y "autoeficacia, para la re-ganancia del peso en pacientes bariátricos. Estudio multivariado predictivo. Se evalúo a 97 pacientes bariátricos. Los resultados indican que las variables psicológicas "locus de control", "presente fatalista" y "pasado positivo" explican el 27.1% de la varianza de la re-ganancia del peso (p<.001). Este modelo clasifica de forma correcta a un 88.7% de los pacientes. Las variables locus de control del peso, pasado positivo y presente fatalista predicen la re-ganancia del peso.

Abstract Bariatric surgery allows a significant and accelerated weight loss in the short term. The regain of the weight is observed between 15 to 30% of the patients. The psychological factors would explain to a greater extent the recovery of weight in bariatric patients. Aim: To evaluate the predictive capacity of the variables "locus of weight control", "temporal perspective" and "self-efficacy", for the re-gain of weight in bariatric patients. Method: Predictive multivariate study. A total of 97 bariatric patients were evaluated. Results: The psychological variables "locus of control", "present fatalist" and "positive past" explain 27.1% of the variance of the regain of weight (p <.001). This model correctly classifies 88.7% of patients. Conclusion: The variables locus of weight control, positive past and fatalistic present predict the regain of weight.

Recuperación de peso perdido en pacientes que han tenido cirugía bariátrica: Una mirada psicológica / Psychological factors influencing weight regain after bariatric surgery

Background Approximately 15 to 40% of bariatric patients regain a significant percentage of their weight lost after surgery. Among psychological variables, control and self-efficacy loci are associated with behaviors related to weight loss. Also, family support can be a risk or protection factor for the maintenance of weight loss. Aim To evaluate the association between psychological variables with weight maintenance or regain after bariatric surgery. Material and Methods We evaluated 97 patients at 4.1 ± 3.4 years after their bariatric surgery. They answered questionnaires about self-efficacy to lose weight, locus of weight control and family functioning style. Regain after surgery was also calculated, through self-report. Results Seventeen percent of patients gained weight. Locus of control (Z = -3.09, p < 0.01), family identity (Z = -3.71, p < 0.01) and self-efficacy (Z = -2.44, p = 0.01), differentiated patients who maintained weight loss from those who re-gained at least 15% of their lost weight. An inverse and significant relationship was observed between the percentage of weight regain and locus of control (r = -0.42, p < 0.01), family identity (r = -0.36, p < 0.01) and self-efficacy (r = -0.34, p <0.01). Conclusions The psychological variables "locus of weight control" and "family identity" are inversely and moderately associated with weight regain in patients subjected to bariatric surgery.

[Psychometric characteristics of the Patient Health Questionnaire (PHQ-9)]. / Propiedades psicométricas del PHQ-9 (Patient Health Questionnaire) en centros de atención primaria de Chile.

BACKGROUND: Simple and brief questionnaires with adequate psychometric properties are useful for the early detection of depressive disorders. AIM: To analyze the psychometric behavior of the Patient Health Questionnaire (PHQ-9) in Chile. MATERIAL AND METHODS: Data were collected from 1,738 adult patients, consulting in primary health care centers. The values obtained in the PHQ-9 were compared with those of the Composite International Diagnostic Interview (CIDI). RESULTS: The mean score of PHQ-9 was 4.85 ± 5.57. Internal consistency indices were high. McDonald's ω coefficient of was 0.90 and Cronbach alpha 0.89. A confirmatory factor analysis showed a good fit of the one-dimensional model. Using a cutoff score of seven determined with the receiver operating characteristic (ROC) curve, the sensitivity and specificity of the instrument were 0.8 and 0.7, when compared with CIDI diagnoses. CONCLUSIONS: PHQ-9 is a useful instrument for the screening of depressive disorders in primary health care centers in Chile.

[Psychological factors influencing weight regain after bariatric surgery]. / Recuperación de peso perdido en pacientes que han tenido cirugía bariátrica: Una mirada psicológica.

Background Approximately 15 to 40% of bariatric patients regain a significant percentage of their weight lost after surgery. Among psychological variables, control and self-efficacy loci are associated with behaviors related to weight loss. Also, family support can be a risk or protection factor for the maintenance of weight loss. Aim To evaluate the association between psychological variables with weight maintenance or regain after bariatric surgery. Material and Methods We evaluated 97 patients at 4.1 ± 3.4 years after their bariatric surgery. They answered questionnaires about self-efficacy to lose weight, locus of weight control and family functioning style. Regain after surgery was also calculated, through self-report. Results Seventeen percent of patients gained weight. Locus of control (Z = -3.09, p < 0.01), family identity (Z = -3.71, p < 0.01) and self-efficacy (Z = -2.44, p = 0.01), differentiated patients who maintained weight loss from those who re-gained at least 15% of their lost weight. An inverse and significant relationship was observed between the percentage of weight regain and locus of control (r = -0.42, p < 0.01), family identity (r = -0.36, p < 0.01) and self-efficacy (r = -0.34, p <0.01). Conclusions The psychological variables "locus of weight control" and "family identity" are inversely and moderately associated with weight regain in patients subjected to bariatric surgery.

Propiedades psicométricas del PHQ-9 (Patient Health Questionnaire) en centros de atención primaria de Chile / Psychometric characteristics of the Patient Health Questionnaire (PHQ-9)

Background: Simple and brief questionnaires with adequate psychometric properties are useful for the early detection of depressive disorders. Aim: To analyze the psychometric behavior of the Patient Health Questionnaire (PHQ-9) in Chile. Material and Methods: Data were collected from 1,738 adult patients, consulting in primary health care centers. The values obtained in the PHQ-9 were compared with those of the Composite International Diagnostic Interview (CIDI). Results: The mean score of PHQ-9 was 4.85 ± 5.57. Internal consistency indices were high. McDonald's ω coefficient of was 0.90 and Cronbach alpha 0.89. A confirmatory factor analysis showed a good fit of the one-dimensional model. Using a cutoff score of seven determined with the receiver operating characteristic (ROC) curve, the sensitivity and specificity of the instrument were 0.8 and 0.7, when compared with CIDI diagnoses. Conclusions: PHQ-9 is a useful instrument for the screening of depressive disorders in primary health care centers in Chile.

Effect of Cholesterol on Membrane Fluidity and Association of Aß Oligomers and Subsequent Neuronal Damage: A Double-Edged Sword.

Background: The beta-amyloid peptide (Aß) involved in Alzheimer's disease (AD) has been described to associate/aggregate on the cell surface disrupting the membrane through pore formation and breakage. However, molecular determinants involved for this interaction (e.g., some physicochemical properties of the cell membrane) are largely unknown. Since cholesterol is an important molecule for membrane structure and fluidity, we examined the effect of varying cholesterol content with the association and membrane perforation by Aß in cultured hippocampal neurons. Methods: To decrease or increase the levels of cholesterol in the membrane we used methyl-ß-cyclodextrin (MßCD) and MßCD/cholesterol, respectively. We analyzed if membrane fluidity was affected using generalized polarization (GP) imaging and the fluorescent dye di-4-ANEPPDHQ. Additionally membrane association and perforation was assessed using immunocytochemistry and electrophysiological techniques, respectively. Results: The results showed that cholesterol removal decreased the macroscopic association of Aß to neuronal membranes (fluorescent-puncta/20 µm: control = 18 ± 2 vs. MßCD = 10 ± 1, p < 0.05) and induced a facilitation of the membrane perforation by Aß with respect to control cells (half-time for maximal charge transferred: control = 7.2 vs. MßCD = 4.4). Under this condition, we found an increase in membrane fluidity (46 ± 3.3% decrease in GP value, p < 0.001). On the contrary, increasing cholesterol levels incremented membrane rigidity (38 ± 2.7% increase in GP value, p < 0.001) and enhanced the association and clustering of Aß (fluorescent-puncta/20 µm: control = 18 ± 2 vs. MßCD = 10 ± 1, p < 0.01), but inhibited membrane disruption. Conclusion: Our results strongly support the significance of plasma membrane organization in the toxic effects of Aß in hippocampal neurons, since fluidity can regulate distribution and insertion of the Aß peptide in the neuronal membrane.

Association between Alzheimer's Disease and Oral and Gut Microbiota: Are Pore Forming Proteins the Missing Link?

Alzheimer's disease (AD) is a neurodegenerative condition affecting millions of people worldwide. It is associated with cerebral amyloid-ß (Aß) plaque deposition in the brain, synaptic disconnection, and subsequent progressive neuronal death. Although considerable progress has been made to elucidate the pathogenesis of AD, the specific causes of the disease remain highly unknown. Recent research has suggested a potential association between certain infectious diseases and dementia, either directly due to bacterial brain invasion and toxin production, or indirectly by modulating the immune response. Therefore, in the present review we focus on the emerging issues of bacterial infection and AD, including the existence of antimicrobial peptides having pore-forming properties that act in a similar way to pores formed by Aß in a variety of cell membranes. Special focus is placed on oral bacteria and biofilms, and on the potential mechanisms associating bacterial infection and toxin production in AD. The role of bacterial outer membrane vesicles on the transport and delivery of toxins as well as porins to the brain is also discussed. Aß has shown to possess antimicrobial activity against several bacteria, and therefore could be upregulated as a response to bacteria and bacterial toxins in the brain. Although further research is needed, we believe that the control of biofilm-mediated diseases could be an important potential prevention mechanism for AD development.

Pre-disaster PTSD as a moderator of the relationship between natural disaster and suicidal ideation over time.

BACKGROUND: Natural disasters are associated with a variety of negative health consequences, including enhanced suicide risk. Factors that moderate the relationship between disaster exposure and enhanced suicide risk are unknown. The aim of the current study was to determine whether pre-disaster PTSD moderates the association between change over time in thoughts of death, suicidal ideation (SI), suicide plans, and suicide attempts (SA) from pre- to post-disaster. METHODS: Participants (n = 2832) were recruited from Chile as part of the larger PREDICT study and completed a measure of lifetime PTSD and panic disorder at baseline and a lifetime death/suicide measure at baseline in 2003 and again 6, 12, and 24 months later (i.e. "pre-disaster"). One year following a major earthquake and tsunami in 2010 (i.e., "post-disaster"), participants completed another death/suicide measure. RESULTS: Both those with and without pre-disaster PTSD experienced significant increases in SI from pre- to post-disaster. However, pre-disaster PTSD was associated with significantly accelerated increases in thoughts of death and SI from pre-to post-disaster. At nearly all time-points, pre-disaster PTSD was associated with higher thoughts of death and SI, suicide planning, and SA. In contrast, panic disorder did not moderate the association between time and changes in SI. LIMITATIONS: There was a long time-gap between pre-disaster and post-disaster, with limited data about what occurred during this time. CONCLUSION: Pre-disaster PTSD is an important predictor of increased SI following a natural disaster, and groups with pre-disaster PTSD should be prioritized for receipt of mental health resources following a natural disaster.

Mental health in the Americas: an overview of the treatment gap.

OBJECTIVE: To understand the mental health treatment gap in the Region of the Americas by examining the prevalence of mental health disorders, use of mental health services, and the global burden of disease. METHODS: Data from community-based surveys of mental disorders in Argentina, Brazil, Canada, Chile, Colombia, Guatemala, Mexico, Peru, and the United States were utilized. The World Mental Health Survey published data were used to estimate the treatment gap. For Canada, Chile, and Guatemala, the treatment gap was calculated from data files. The mean, median, and weighted treatment gap, and the 12-month prevalence by severity and category of mental disorder were estimated for the general adult, child-adolescent, and indigenous populations. Disability-adjusted Life Years and Years Lived with Disability were calculated from the Global Burden of Disease study. RESULTS: Mental and substance use disorders accounted for 10.5% of the global burden of disease in the Americas. The 12-month prevalence rate of severe mental disorders ranged from 2% - 10% across studies. The weighted mean treatment gap in the Americas for moderate to severe disorders was 65.7%; North America, 53.2%; Latin America, 74.7%; Mesoamerica, 78.7%; and South America, 73.1%. The treatment gap for severe mental disorders in children and adolescents was over 50%. One-third of the indigenous population in the United States and 80% in Latin America had not received treatment. CONCLUSION: The treatment gap for mental health remains a public health concern. A high proportion of adults, children, and indigenous individuals with serious mental illness remains untreated. The result is an elevated prevalence of mental disorders and global burden of disease.

Mental health in the Americas: an overview of the treatment gap / La salud mental en las Américas: una visión general de la brecha de tratamiento / Saúde mental nas Américas: uma visão geral da lacuna de tratamento

ABSTRACT Objective To understand the mental health treatment gap in the Region of the Americas by examining the prevalence of mental health disorders, use of mental health services, and the global burden of disease. Methods Data from community-based surveys of mental disorders in Argentina, Brazil, Canada, Chile, Colombia, Guatemala, Mexico, Peru, and the United States were utilized. The World Mental Health Survey published data were used to estimate the treatment gap. For Canada, Chile, and Guatemala, the treatment gap was calculated from data files. The mean, median, and weighted treatment gap, and the 12-month prevalence by severity and category of mental disorder were estimated for the general adult, child-adolescent, and indigenous populations. Disability-adjusted Life Years and Years Lived with Disability were calculated from the Global Burden of Disease study. Results Mental and substance use disorders accounted for 10.5% of the global burden of disease in the Americas. The 12-month prevalence rate of severe mental disorders ranged from 2% - 10% across studies. The weighted mean treatment gap in the Americas for moderate to severe disorders was 65.7%; North America, 53.2%; Latin America, 74.7%; Mesoamerica, 78.7%; and South America, 73.1%. The treatment gap for severe mental disorders in children and adolescents was over 50%. One-third of the indigenous population in the United States and 80% in Latin America had not received treatment. Conclusion The treatment gap for mental health remains a public health concern. A high proportion of adults, children, and indigenous individuals with serious mental illness remains untreated. The result is an elevated prevalence of mental disorders and global burden of disease.

RESUMEN Objetivo Comprender la brecha en el tratamiento de la salud mental en la Región de las Américas mediante la revisión de la prevalencia de los trastornos de salud mental, el uso de los servicios de salud mental y la carga mundial de enfermedad. Métodos Se utilizaron datos de encuestas comunitarias de trastornos mentales de Argentina, Brasil, Canadá, Chile, Colombia, Estados Unidos, Guatemala, México y Perú. Se emplearon los datos publicados de la Encuesta Mundial de Salud Mental para estimar la brecha de tratamiento. Para Canadá, Chile y Guatemala, la brecha de tratamiento se calculó a partir de los archivos de datos. Se estimaron la brecha de tratamiento media, media ponderada, y mediana, y la prevalencia de 12 meses por gravedad y categoría de trastorno mental para las poblaciones generales de adultos, niños y adolescentes, e indígenas. Se calcularon los años de vida ajustados por discapacidad y los años vividos con discapacidad a partir del estudio Carga Global de Enfermedad. Resultados Los trastornos mentales y por consumo de sustancias representaron el 10,5% de la carga mundial de enfermedad en las Américas. La tasa de prevalencia de 12 meses de los trastornos mentales severos varió del 2% al 10% en los estudios. La brecha de tratamiento media ponderada en las Américas para los trastornos moderados a graves fue del 65,7%; en América del Norte de 53,2%; en América Latina de 74,7%; en Mesoamérica de 78,7%; y en América del Sur de 73,1%. La brecha de tratamiento para los trastornos mentales graves en niños y adolescentes fue superior al 50%. Un tercio de la población indígena en los Estados Unidos y el 80% en América Latina no recibieron tratamiento. Conclusión La brecha de tratamiento para la salud mental sigue siendo un problema de salud pública. Una gran proporción de adultos, niños y personas indígenas con enfermedades mentales graves continúan sin tratamiento. El resultado implica una prevalencia elevada de trastornos mentales y de la carga mundial de enfermedad.

RESUMO Objetivo Compreender a lacuna de tratamento em saúde mental na Região das Américas examinando a prevalência de transtornos mentais, o uso de serviços de saúde mental e a carga global de doença. Métodos Foram utilizados dados de inquéritos comunitários de transtornos mentais na Argentina, Brasil, Canadá, Chile, Colômbia, Guatemala, México, Peru e Estados Unidos. Os dados publicados na Pesquisa Mundial de Saúde Mental foram utilizados para estimar a lacuna de tratamento. Para o Canadá, Chile e Guatemala, a lacuna de tratamento foi calculada a partir de arquivos de dados. A lacuna de tratamento média, média ponderada e mediana, e a prevalência de 12 meses por gravidade e categoria de transtorno mental foram estimadas para as populações adulta, infantil-adolescente e indígena em geral. Os anos de vida ajustados por incapacidade e os anos de vida com incapacidade foram calculados a partir do estudo Carga Global de Doença. Resultados Os transtornos mentais e de uso de substâncias foram responsáveis por 10,5% da carga global de doença nas Américas. A taxa de prevalência de 12 meses de transtornos mentais graves variou de 2% a 10% entre os estudos. A lacuna de tratamento média ponderada nas Américas para transtornos moderados a graves foi de 65,7%; em América do Norte de 53,2%; em América Latina de 74,7%; em Mesoamérica de 78,7%; e na América do Sul de 73,1%. A lacuna de tratamento para transtornos mentais graves em crianças e adolescentes foi superior a 50%. Um terço da população indígena nos Estados Unidos e 80% na América Latina não recebeu tratamento. Conclusão A lacuna de tratamento para a saúde mental continua sendo uma preocupação de saúde pública. Uma alta proporção de adultos, crianças e indígenas com doença mental grave permanece sem tratamento. O resultado é uma elevada prevalência de transtornos mentais e de carga global de doença.