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The giant gypsum crystals of Naica cave have fascinated scientists since their discovery in 2000. Human activity has changed the microclimate inside the cave, making scientists wonder about the potential environmental impact on the crystals. Over the last 9 years, we have studied approximately 70 samples. This paper reports on the detailed chemical–structural characterization of the impurities present at the surface of these crystals and the experimental simulations of their potential deterioration patterns. Selected samples were studied by petrography, optical and electronic microscopy, and laboratory X-ray diffraction. 2D grazing incidence X-ray diffraction, X-ray μ-fluorescence, and X-ray μ-absorption near-edge structure were used to identify the impurities and their associated phases. These impurities were deposited during the latest stage of the gypsum crystal formation and have afterward evolved with the natural high humidity. The simulations of the behavior of the crystals in microclimatic chambers produced crystal dissolution by 1–4% weight fraction under high CO2 concentration and permanent fog, and gypsum phase dehydration under air and CO2 gaseous environment. Our work suggests that most surface impurities are of natural origin; the most significant anthropogenic damage on the crystals is the extraction of water from the caves.
Startle reflex (SR) is a defensive response to sudden, intense stimuli. Prepulse inhibition (PPI) refers to the ability of innocuous sensory events to reduce SR. PPI has been described as an operational measure of sensorimotor gating that is reduced in several neuropsychiatric disorders, such as schizophrenia, but there is no extensive experience in addictions and alcoholism. The objective of this study was to examine the existence of impairments on SR and PPI in abstinent alcoholic males.
Subjects were 40 abstinent alcoholic males, aged 18 to 65 years (mean age 44.73), who had met DSM-IV criteria for Alcohol Dependence, being abstinent for more than a month at the moment they were tested. Participants underwent testing for PPI. Subjects were then compared with 35 equal controls.
Magnitudes of the SR were lower in abstinent alcoholic males when compared with controls. This differences were significant (p< 0,05) in trials with prepulse presented 30, 60 or 120 msec before the onset of startle stimulus. There was a significant less percentage of PPI when prepulse was presented 30 msec before the startle stimulus (p< 0,05).
Abstinent alcoholic males exhibit a decrease in the startle response magnitude and in the PPI of the SR. These data suggest that sensory information processing mechanisms could be damaged in abstinent alcoholic patients. The fact that these findings are common to other psychiatric disorders, could indicate the existence of a common vulnerability marker, and could explain the important comorbidity between alcoholism and other mental illness.
Impulsivity is associated with different types of disorders, included substance used disorders. The purposed of this study is get to know if alcohol and cocaine affect in the same way to the impulsivity paradigms or if they strength each other or if there are specific bias associated to each one of the substances.
Material and methods
This is a 380 heavy drinker patient's sample recruited from twelve primary care centers. The patients were screened using The Alcohol Use Disorders Identification Test (AUDIT > 8). Neuropsicological tests done at the base line and after the 4 years of the study were the Continous Performance Test (CPT) and the Barrat Impulsivity scale. The alcohol and cocaine consume accumulated along the four years was also study.
The two variables of the CPT (ommission and commission errors) had a significant correlation with the alcohol and cocaine use accumulated in these four years. The variable that was associated with a greater risk of making more commission and ommission errors was the cocaine risk consumption. The years of study were protective variable.
The most important conclusion of this study is that alcohol and cocaine use produces a modification in the conductual paradigm of impulsivity characterized by the inhibition difficulties measured by the CPT. Also, the cocaine use effects are added respect to the alcohol ones and finally that cocaine plus alcohol effects over the number of ommission and commission errors are more potent that the ones made only with alcohol.
Impulsivity has been considered as a risk factor for alcohol dependence. Recent research is focusing on paradigms of the startle response (SR), specifically prepulse inhibition (PPI) and startle habituation (SH), as vulnerability markers for alcoholism. It has been demonstrated impairments in the PPI and the SH in offspring of alcoholics. It has also been shown, using personality questionnaires, that faster habituation may be associated with tendency toward impulsivity and behavioral disinhibition. Our goal is to study the correlation between impulsivity laboratory measures and the SR paradigms, in order to see if they could share a common base as endophenotypes for alcoholism.
The subjects were 40 abstinent alcoholic males, aged 18 to 65 years (mean age 44.73) and who had met DSM-IV criteria for Alcohol Dependence, being abstinent for more than a month at the moment they were tested. Participants underwent testing for PPI and habituation of the acoustic startle response. Impulsivity was assessed with three different laboratory measures: Continuous Performance Test (CPT), Stop-Signal Task and Differential Reinforcement for Low-Rate Responding (DRL6). Analyses were performed using SPSS v.10.0.
We found a significant positive correlation between CPT-tasks and SH (p< 0,01), and Stop-Signal Task-tasks and SH (p< 0,05), but not with DRL6-tasks. No significant correlation was demonstrated between impulsivity measures and PPI.
Our findings suggest the existence of a common base between impulsivity and SH as vulnerability markers for alcohol dependence. Further studies are needed to assess if both could share a common genetic origin.
Presence of A1 allele of the DRD2 gene has been associated with a predisposition for alcoholism although there are limited data about its phenotypic expression in alcoholism.
To determine the importance of the A1 allele in clinical variables of alcohol dependence.
A sample of 103 alcohol-dependent males was studied. All patients were recruited consecutively from the general hospital and community settings. The diagnostics were made with the structured clinical interview for DSM-III-R (SCID); and the International Personality Disorder Examination (IPDE). Diagnosis of family alcoholism was made by direct interview or with the Research Diagnostic Criteria-Family History (RDC-FH). The Addiction Severity Index (ASI) and the Severity of Alcohol Dependence Scale (SADS) were used to assess alcohol dependence severity. Genotyping was done by polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) methods.
Approximately 39% of the sample carried the A1 allele (A1+ group). This group had higher prevalences of antisocial personality disorder (60% vs. 15.9%); and alcoholism family history (72.5% vs. 52.4%). Also A1+ had early onset alcohol abuse and more drinking problems. The presence of A1+ was the main factor to explain the diagnosis of antisocial personality disorder, but the weight of this factor was not sufficient to explain the complications assessed by the ASI.
Our results support the existence of an association between the A1 allele and factors resulting from dopaminergic deficiency, otherwise denominated reward deficiency syndrome.
Two laboratory paradigms identifying two behavioral processes have been used to measure impulsivity. The first relates to behavioral inhibition, i.e., the ability to inhibit thoughts or actions appropriately. The second pertains to the degree to which immediate rewarding consequences have more control over behavior than delayed consequences. Behavioral impulsivity disorders have been associated with alcohol dependence. Topiramate has been used to treat many disorders characterized by impulsivity symptoms. Reports also suggest that topiramate has utility in treating a variety of addictive disorders. Little is known, however, about whether its anticraving effects are related to its impulsivity-reducing actions. The aim of this preliminary study was to investigate which type/dimension of behavioral impulsivity was associated with topiramate's anticraving effects. A 12-week, double-blind, placebo-controlled pilot study of topiramate for treating alcohol dependence was conducted. Subjects were men recruited from alcoholism treatment units (topiramate=21; placebo=20). The continuous performance test and stop-signal task assessed behavioural inhibition. Differential reinforcement for low-rate responding was used to evaluate the delay discounting dimension. Alcohol craving and the amount of alcohol consumed during the study also were assessed. Topiramate-treated patients had lower rates of alcohol consumption and significantly lower alcohol craving scale scores than controls, and exhibited greater improvements in the behavioural inhibition and delay discounting paradigms. Improvement in alcohol craving was associated with better performance on the behavioural inhibition paradigm. Our findings suggest that topiramate's anticraving actions could be related to its effects on behavioural inhibition. More studies are needed to confirm and understand this link.
The TaqIA polymorphism linked to the DRD2 gene has been associated with alcoholism. The aim of this work is to study attention and inhibitory control as per the continuous performance test and the stop task in a sample of 50 Spanish male alcoholic patients split into two groups according to the presence of the TaqIA1 allele in their genotype. Our results show that alcoholics carrying the TaqIA1 allele present lower sustained attention and less inhibitory control than those patients without such allele.
Different neuropsychological studies have consistently found an attention, memory and executive function deficit in schizophrenic patients. The Positive and Negative Syndrome Scale (PANSS) evaluates different clinical aspects of schizophrenia. Factor analyses of this scale suggest the existence of a “cognitive factor”, constituted by several items pertaining to the different subscales. In order to have an acceptable concurrent validity, this “cognitive factor” should correlate with the execution of neuropsychological tasks. Our objective was to study the correlation between the PANSS “cognitive factor” and the execution of neuropsychological tasks evaluating attention, memory and executive functions.
Thirty-five schizophrenic patients were evaluated using the Continuous Performance Test (CPT), the Rey-Osterrieth Complex Figure Test (Rey CFT) and the Wisconsin Card Sorting Test (WCST). Bivariate partial correlation between the neuropsychological variables and the PANSS “cognitive factor” was examined. In order to obtain this cognitive component, and based on previous studies, items P2, N5, PG10 and PG11 were used.
The PANSS “cognitive factor” was significantly correlated to CPT omission errors (r=0.45; p=0.006), Rey CFT recall after 5 minutes (r=-0.34; p=0.049), Rey CFT recall after 30 minutes (r=-0.40; p=0.020), WCST perseverative responses (r=0.36; p=0.035), and WCST perseverative errors (r=0.35; p=0.041).
The existence of significant correlations between the PANSS “cognitive factor” and performance on neuropsychological tasks evaluating attention (CPT), memory (Rey CFT) and executive functions (WCST) supports the concurrent validity of this factor.
A high prevalence of childhood attention-deficit/hyperactivity disorder (ADHD) history has been found in alcoholic patients. Patients with this history have an earlier onset and greater intensity of alcohol use, more polysubstance use and a poorer prognosis. Our objective was to study differences in neuropsychological functioning in a group of alcoholic patients according to the presence or absence of a history of childhood ADHD.
A sample of 136 male alcoholic patients and 56 male control subjects were evaluated using the Continuous Performance Test (CPT); execution in both groups was compared. The sample of alcoholic patients was then divided into two subgroups according to the presence or absence of a history of childhood ADHD, namely the ADHD+ OH subgroup (61 patients with childhood ADHD history) and the ADHD- OH subgroup (75 patients without this history); CPT execution in these two subgroups was also compared.
The group of alcoholic patients made more omission (p=0.008) and commission (p=0.009) errors in the CPT than the control group. When comparing subgroups, ADHD+ OH patients made more omission and commission errors than ADHD- OH patients, although the differences did not reach statistical significance.
Alcoholic patients perform more poorly on the CPT than control subjects. In the sample of alcoholic patients, a history of childhood ADHD was not associated to significant differences in the execution of this test.
Different types of behavioural impulsivity have been associated with the development of substance use disorders but little is know about what type of impulsivity is provoked by the effect of chronic use of substances.
Determine what type of behavioural impulsivity was associated with the use of alcohol and cocaine.
Design and measurements:
A prospective cohort study was conducted to identify changes on behavioural impulsivity. Non-dependent heavy drinkers (N=471) were recruited from primary care centres. The following assessments were used at baseline and at the end of the 4-year follow-up period: The continuous performance test (CPT) and stop-signal task (SST) assessed behavioural inhibition. Differential reinforcement for low-rate responding (DRLR) was used to evaluate the delay discounting dimension. Diagnoses were rendered using the Structured Interview for DSM-IV.
Amounts on alcohol and cocaine consumption during follow-up correlated positively with changes on all impulsivity measures. Logistic regression analysis indicated that cocaine used was associated specifically with poor performance on CPT and SST and amount of alcohol used during follow-up was related to changes on DRLR.
Substances provoke different pattern of behavioural impulsivity: chronic cocaine use provokes changes mainly on behavioural inhibition dimension and alcohol use induces changes on delay discounting paradigm.
Smoking is an important health problem associated with different medical and psychiatric disorders. A high prevalence of smoking has been described in psychiatric patients. Our objective was to determine the prevalence of smoking in inpatients admitted to a psychiatric hospitalisation unit in a general hospital, and to study the possible differences in this prevalence according to the different psychiatric diagnoses.
A retrospective analysis of the medical records and discharge reports of the 659 patients admitted to our psychiatric hospitalisation unit during three consecutive years (2003-2005) was carried out.
At the time of their admission, 70.2% of our patients were smokers. This percentage reached 97.2% among patients with substance-use disorders (SUDs), and 95.5% among patients with dual diagnosis. However, only 48.6% of patients without concurrent SUDs were smokers; this difference reached statistical significance (p<0.001). According to psychiatric diagnosis, significant differences were also found regarding the percentage of smokers: 83.0% in schizophrenia, 80.0% in schizophreniform disorder, 70.7% in bipolar disorder, 29.3% in major depressive disorder and 56.8% in other disorders (p<0.001).
Although smoking prevalence among psychiatric patients is higher than in the general population, differences were found between the various psychiatric diagnoses. Thus, the prevalence of smoking was highest among psychotic patients and among those with concurrent use of other substances, whilst depressive patients had rates of smoking similar to those of the general population.
The Positive and Negative Syndrome Scale (PANSS) evaluates different psychopathological aspects of schizophrenic patients. Scores on the negative subscale of the PANSS have been associated with clinical and neuropsychological differences in these patients. Our aim was to study the relationship between PANSS negative scores and different clinical and neuropsychological variables in a sample of schizophrenic patients.
Our sample of 174 schizophrenic patients was split into two groups according to scores on the negative subscale of the PANSS: a group of 85 patients (55 male and 30 female; mean age 38.0 years, SD 9.3) with scores below the median (“low negative PANSS” group), and a group of 89 patients (58 male and 31 female; mean age 37.3, SD 8.4) with scores above the median (“high negative PANSS” group). The neuropsychological task used was the Wisconsin Card Sorting Test.
Significant clinical differences were found between both groups. In the “high negative PANSS” group a lower age of illness onset was found (p=0.030), as well as a lower age at first psychiatric admission (p=0.002) compared to the “low negative PANSS” group, without there being significant differences in current age (p=0.570). Regarding cognitive functions, “high negative PANSS” patients achieved fewer categories (p=0.005) and made more perseverative errors (p=0.031) than “low negative PANSS” patients.
Schizophrenic patients with higher scores on the negative subscale of the PANSS had an earlier age of onset of their illness and exhibited poorer cognitive functioning than patients with lower scores.
The link between impulsivity and alcohol use disorders has been established in longitudinal and cross-sectional studies, but little is know about the role of behavioural impulsivity in the development of substance use disorders.
Determine the role of behavioural measures of impulsivity in the development of alcohol use disorders.
Design and measurements:
A prospective cohort study was conducted to identify the risk factors associated with alcohol dependence. Non-dependent heavy drinkers (N=471) and healthy controls (N=149) were recruited from primary care centres. They were assessed at the end of the 4-year follow-up period. Diagnoses were rendered using the Structured Interview for DSM-IV. The continuous performance test (CPT) and stop-signal task (SST) assessed behavioural inhibition. Differential reinforcement for low-rate responding (DRLR) was used to evaluate the delay discounting dimension.
HD participants have significant impairments on all laboratory measures of impulsivity. In the logistic regression model, impairment on DRLR (delay discounting dimension) was the only measure that classified accurately HD. Baseline behavioural measures of impulsivity correlated positively with amount of alcohol consumption during the follow-up period. Logistic regression analysis indicated that performance on inhibitory control (SST) (behavioural inhibition dimension) was a significant predictor (odds=1.52[1.08-2.31]) for developing alcohol dependence.
Our data support the link between behavioural measures of impulsivity and alcohol use disorders. Delay discounting dimension may be a risk factor for begin alcohol use heavily and behavioural inhibition impairment is more involved in the development of dependence.
The Wender-Utah Rating Scale (WURS) was developed for the retrospective diagnosis of childhood attention-deficit/hyperactivity disorder (ADHD). It consists of a list of childhood behaviours and symptoms suggestive of ADHD. Our objective was to study correlations of WURS scores with different impulsivity, personality, anxiety and depression psychometric scales.
A group of 110 healthy university students were evaluated using the WURS. Four subjects scored higher than the cut-off value of 37 (compatible with childhood ADHD) and were excluded. The Barratt Impulsivity Scale (BIS-11), the Big Five Questionarie (BFQ), the State-Trait Anxiety Inventory (STAI) and the Beck Depression Inventory (BDI) were administered. Partial bivariate correlation analyses were performed.
WURS scores were correlated with total scores on the BIS-11 (r=0.430; p<0.001), as well as with the motor (r=0.410; p<0.001), attentional (r=0.328; p=0.001), and improvisation subscales (r=0.289; p=0.003). Regarding the BFQ, a correlation was found between WURS scores and the “emotional stability” factor (r=-0.379; p<0.001) as well as with the subfactors “emotion control” (r=-0.310; p=0.001) and “impulse control” (r=-0.354; p<0.001). Finally, significant correlations were also found between WURS scores and scores on the STAI-trait (r=0.366; p<0.001), STAI-state (r=0.200; p=0.039), and the BDI (r=0.350; p<0.001).
Correlations between the WURS and other impulsivity-related psychometric scales such as the BIS-11, or the “emotional stability” factor and the “emotion control” and “impulse control” subfactors of the BFQ, provides evidence for the concurrent validity of the WURS. The correlation of this instrument with anxiety and depression scales points to possible clinical implications.
Impulsivity has been associated with alcohol dependence, but impulsivity in alcohol-dependent subjects has not been well characterized.
Using a variety of laboratory measures of impulsivity, we assessed whether alcohol-dependent patients (ADP) were more impulsive than control subjects, and the role of Cluster-B personality disorders in impulsivity measurements.
Design and measurements:
A cross-sectional patient survey with a community comparison group. Diagnoses were made using the Structured Interview for DSM-IV. Sustained attention and rapid-response impulsivity were assessed using the continuous performance test (CPT). Inhibitory control was measured by the stop-signal task (SST). Ability to delay reward task was assessed using differential reinforcement for low-rate responding (DRLR).
Participants and setting:
A final sample of 253 males with alcohol-dependence recruited from two alcoholism treatment centres was compared with a matched non-substance-abusing comparison group (n=96).
Patients with alcohol dependence were more impulsive across all behavioural tasks. Alcohol-dependent subjects without personality disorders showed lower efficiency in DRLR than control subjects. Patients with Cluster-B personality disorder performed worse in inhibitory control, but subjects with borderline personality disorder in particular demonstrated increased rates of omission and commission errors in CPT. Inability to delay gratification was associated with antisocial personality disorder.
Our findings support the suggestion of two paradigms in alcohol dependence. The first, based on inability to delay gratification, might be a vulnerability marker for alcohol dependence. The second was related to inhibitory control, and might be specific for antisocial and borderline personality disorders.
Different personality factors have been investigated in connection with addictive disorders such as pathological gambling. “Impulse control”, proposed as a dimension of personality in modern “Big Five” models, has been associated with pathological gambling. Pathological gamblers have a high prevalence of childhood attention-deficit/hyperactivity disorder (ADHD), which is also associated with high impulsivity. Based on a five-factor personality model, our objective was to compare different personality dimensions in a group of pathological gamblers with childhood ADHD history, a group of pathological gamblers without such history and a control group. Special emphasis was placed on the factor “emotional stability”, which includes the subdimensions “emotion control” and “impulse control”.
A sample of 30 pathological gamblers with childhood ADHD history (ADHD+PG group), 33 pathological gamblers without ADHD history (ADHD-PG group) and 42 control subjects were assessed using the Big Five Questionnaire (BFQ). The different BFQ dimensions and subdimensions were compared.
For the “emotional stability” factor, the T-scores obtained indicated statistically significant differences between groups (ADHD+PG group: 44.1; ADHD-PG group: 51.9; control group: 57.9; ANOVA, p<0.001). Scheffe´s post hoc analysis showed the ADHD+PG group to be less emotionally stable than both the ADHD-PG (p=0.002) and the control groups (p<0.001); the ADHD-PG group also scored lower on this “emotional stability” factor than the control group (p=0.015).
Pathological gamblers with a history of childhood ADHD exhibit differential personality traits. ADHD history is associated with a lower score on the “emotional stability” factor, which includes the subdimensions “emotion control” and “impulse control”.
Fibromyalgia and ADHD share some clinical features, and a reduced dopamine function has been proposed for both disorders. Here we found, in a large sample of fibromyalgia female patients, a higher frequency of childhood ADHD antecedent when compared with healthy women. Our data suggest that Fibromyalgia and ADHD have some common etiopathological mechanism.
Pathological gambling is often considered a behavioral addiction. Attentional bias (AB) refers to the observation that substance-related cues tend to grab the attention of experienced substance users. The Dot Probe Task has been used to assess AB in individuals with substance addiction, however it has never been used to assess AB in PG.
The aims of the present study are assessing potential AB in PG using Dot Probe Task with exposures time that assess attentional maintenance checking the possible correlation of PG severity with degree of attentional bias.
PG sample was 23 subjects and Non Gamblers group (NG) was 21 subjects. To asses the severity of gambling we use the South Oaks Gambling Screen. We can define two types of reaction times to assess the AB: a) Congruence time: time the subject takes to detect the point when it appears on the hemi-screen replacing the cue picture. b) Non-congruence time: idem when replacing the neutral picture. The difference between these times is the AB index.
The PG had a congruence time significantly lower than the non-congruence time which indicates the presence of AB in this group. There were also differences between AB index in PG and NG sample, validating the Dot Probe task to detect AB. Moreover, there weren’t relation between the severity of the game and AB.
The study shows the presence of AB in PG at level of maintenance of attention (disengagement) and the validity of Dot Probe Task to detect AB in PG.
It is considered that cocaine could be a risk factor for the development of alcohol dependence. Prospective studies in healthy subjects support the idea that alcohol and cocaine use decreases the subjective feeling of inebriation and increases the sense of being “high”. The consumption of both drugs may accentuate the reinforcing properties of both drugs, thus increasing the vulnerability of subjects for developing drug dependence. Our objective was to investigate whether the risk for the development alcohol dependence is related with the interaction of both drugs at reward brain mesolimbic centres or it depends on the effect of cocaine at that brain mesolimbic structures.
The final sample (n = 112) comprised 4 groups: sample 1(alcohol-group), n = 47; sample 2 (alcohol-cocaine group), n = 35; sample 3 (cocaine-group), n = 30. The control group (n = 61) was selected to have matching demographic characteristics. After detoxification, alcohol-related pictures were compared to standardised appetitive, aversive and neutral control scenes using an acoustic-startle test.
Alcohol-startle magnitudes were lower in cocaine-dependent patients (samples 2 and 3) than in alcohol patients (sample 1). Subjects with cocaine dependence also exhibited lower magnitudes than participants included in the OH-group after viewing appetitive and aversive slides.
Our findings support the hypothesis that effects of cocaine at dopamine mesolimbic structures provoke higher appetitive responses to alcohol-cues. It is tempting to speculate that cocaine use may induce significant reduction in dopamine D2 receptors, which would increase the likelihood of developing dependence for other substances as alcohol used at the same time than cocaine.
Pathological Gambling (PG) tends to be a heterogeneous disorder where patients differ with type and severity of gambling behaviour, psychiatric co-morbidity, family history, sex and age of onset. Age of disease onset in PG varies significantly, with many individuals having onset during childhood and adolescence and others in various stages of adulthood. Previous studies have demonstrated that age of onset is an important characteristic for a better understanding of the PG heterogeneity.
(1) To analyze differences in sociodemographic aspects between early-onset PG and non early-onset PG, (2) to study whether early-onset PG is associated with specific psychiatric diagnosis in axis I and II.
We used data from a large and nationally representative community sample of United States (US) adults, the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC). We selected age 25 years as a threshold for early-onset PG.
Individuals with early-onset PG were more likely to be male, never married, and young and to have a lower education level and individual income than non early-onset PGs. Early-onset PG were less likely to have mood disorder (OR = 0.42 (0.19 − 0.94)) and had non-significant higher odds of having substance and anxiety disorders than non early-onset. The odds of having Cluster B disorder were significantly higher among early-onset PGs than non early-onset PGs (OR = 4.11 (1,77 − 9.55)).
Our findings support that subgroups of Pathological Gambling defined by onset age have phenotypic differences.