Hug drug or thug drug? Ecstasy use and aggressive behavior

While clinical studies have established a link between aggression and ecstasy (3,4-methylenedioxymeth-amphetamine [MDMA]), no research has attempted to explore how this link manifests itself in behavioral outcomes. In this research we examine the effects of ecstasy on aggressive and violent behavior in a sample of active users. Data were collected from 260 ecstasy users in Atlanta, Georgia. Data analysis included ordered logit regression to examine the likelihood of engaging in aggressive behavior, controlling for key predictors of aggression independent of ecstasy use. Our results indicate that those with a higher prevalence of lifetime ecstasy use exhibit higher levels of aggressive and violent behavior. However, the effect of lifetime ecstasy use differs by levels of low self-control as a measure of propensity for aggression. Those who exhibit low self-control are more affected by ecstasy use than those who do not in terms of aggression. Our findings add an important dimension to our current knowledge about the relationship between aggression and ecstasy.

An investigation into the sub-acute effects of ecstasy on aggressive interpretative bias and aggressive mood - are there gender differences?

The lowering of serotonin for a period following MDMA use could account for the increases in both self-rated and objective measures of aggression previously found in ecstasy users several days after taking the drug. There is some evidence of gender differences in the acute, sub-acute and long-term effects of MDMA use, and given that gender differences have been found in aggression, it is possible that men may experience more aggression mid-week than women. The aim of this study was to attempt to replicate findings showing increased bias towards aggressive material in ecstasy users several days after using the drug. In addition, to investigate possible gender differences in mid-week aggression. A total of 46 participants were tested: 19 ecstasy users and 27 controls were compared on the night of drug use and 4 days later. On day 4, a task designed to tap cognitive bias toward material with aggressive content was administered. Participants were required to process sentences that could be interpreted as either aggressive or neutral and subsequently remember them in a recognition test. This data set was then combined with the data from Curran et al.'s (2004) study that employed exactly the same procedure. Thus, the data from 107 participants was analysed to investigate gender differences. Ecstasy users recognized more aggressive sentences than controls and tended to react slower to neutral sentences than controls. Ecstasy users also rated themselves as being more aggressive and depressed than controls on day 4. No gender differences were found on any measure of aggression in the combined data set. Both male and female ecstasy users show a bias toward interpretation of ambiguous material in an aggressive manner when compared to controls 4 days after ecstasy use.

Neurocognitive consequences of marihuana--a comparison with pre-drug performance

In determining the effects of regular marihuana use on neurocognition, abilities within specific relevant cognitive domains prior to regular drug use have not been available. The present study examined effects of current and past regular use of marihuana in subjects for whom pre-drug performance had been ascertained in a prospective, longitudinal fashion. A total of 113 young adults, assessed since infancy, were evaluated using neurocognitive tests for which commensurate measures were obtained prior to the initiation of marihuana smoking. Marihuana users, determined by urinalysis and self-report, were categorized as light (< 5 joints per week) and heavy (> or = 5 joints per week) current users and former users, the latter having used the drug regularly in the past (> or = 1 joint per week) but not for at least 3 months. A third of the subjects were using marihuana on a regular basis at the time of assessment with half being heavy users. Among former, regular users, approximately half had been smoking 5 or more joints per week. Overall IQ, memory, processing speed, vocabulary, attention, and abstract reasoning were assessed. After accounting for potentially confounding factors and pre-drug performance in the appropriate cognitive domain, current regular heavy users did significantly worse than non-users in overall IQ, processing speed, immediate, and delayed memory. In contrast, the former marihuana smokers did not show any cognitive impairments. It was concluded that residual marihuana effects are evident beyond the acute intoxication period in current heavy users after taking into account pre-drug performance but similar deficits are no longer apparent 3 months after cessation of regular use, even among former heavy using young adults.

Comparison of neurocognition between drug-free patients with schizophrenia and bipolar disorder

It is often difficult to make a differential diagnosis between schizophrenia and bipolar disorder because of the overlapping symptoms. The patients of both disorders have been shown to have neurocognitive deficits. In this study, a computerized battery of neurocognitive tasks, COGLAB, was administered to four participant groups: 30 patients with positive schizophrenia, 22 patients with negative schizophrenia, 27 patients with bipolar disorder, and 28 normal controls. All the patients were drug-free for at least 1 month. The tasks included Mueller-Lyer illusion, reaction time, size estimation, a variant of the Wisconsin Card Sorting Test, backward masking, and Asarnow continuous performance. Discriminant analyses were used to investigate the differences among the four groups. Results indicated that COGLAB correctly classified 73.5% of the cases of negative schizophrenia and bipolar disorder. The best discriminative tasks were card sort, Asarnow continuous performance, and backward masking. The results of this study were also compared with results of a previous study with medicated patients. Neurocognitive tasks had better discriminative power for medicated patients with schizophrenia and bipolar disorder than for drug-free patients. Moreover, medication effects did not seem to significantly change the pattern of the neurocognitive task responses of patients with schizophrenia.

Executive function in schizophrenia: is it linked to psychosis and poor life functioning?

The authors examined the relationship of major aspects of executive function to acute psychosis and long-term outcome in patients enrolled in a 15-year study of the natural history of psychosis. They evaluated 157 patients, including 42 schizophrenic, 42 other psychotic, and 73 nonpsychotic psychiatric patients 15 years after index hospitalization. Patients were administered the Wisconsin Card Sorting Test (WCST) and measures of psychosis and posthospital adjustment. Schizophrenia patients performed significantly worse than both nonschizophrenic psychiatric control groups on WCST indices, regardless of psychosis. Aspects of executive function were impaired in schizophrenia patients with severe deficits in their level of overall functioning and outcome and also in many with only moderate impairment in overall functioning; however, these deficits were seen to a greater degree in schizophrenia patients with very poor overall functioning. Executive function deficits appear to be a core component of schizophrenia rather than an effect of acute psychotic disorganization, and are associated with long-term outcome.

Cognitive impairment in methadone maintenance patients

Few well-controlled studies have examined psychomotor and cognitive performance in methadone maintenance patients (MMP). In the present study, performance of 18 opioid-dependent MMP was evaluated relative to that of 21 control participants without substance abuse histories. The MMP and control groups were balanced with respect to gender, race, age, years of education, current employment status, current reading level, and estimated IQ score. Recent drug abstinence was verified by urine testing. Participants with a urine screen positive for benzodiazepines or a breathalyzer test positive for alcohol prior to performance testing were excluded. To avoid testing under conditions of acute heroin or cocaine intoxication, but without testing under conditions of acute withdrawal, participants with current use of heroin or cocaine were only required to abstain for 24 h prior to performance testing. MMP exhibited impairment relative to controls in psychomotor speed (digit symbol substitution and trail-making tests), working memory (two-back task), decision making (gambling task), and metamemory (confidence ratings on a recognition memory test); results also suggested possible impairment in inhibitory mechanisms (Stroop color-word paradigm). MMP did not exhibit impairment in time estimation, conceptual flexibility or long-term memory. The wide range of impaired functions is striking, and may have important implications for daily functioning in MMP. Further research is necessary to determine the clinical significance of the impairments in laboratory-based tests for daily performance in the natural environment, as well as to differentiate impairments due to acute methadone dosing, chronic methadone maintenance, chronic poly-drug abuse, and other factors.

Use of a false recognition paradigm in an Alzheimer's disease clinical trial: a pilot study

We report the first use of a false recognition memory test in a clinical trial of patients with Alzheimer's disease (AD). Tests of false recognition allow measurement of two components of memory: the specific details of a prior encounter with a particular item (item-specific recollection) and the general meaning, idea, or gist conveyed by a collection of items (gist memory). We used a false recognition paradigm with categorized pictures to study the effects of an experimental medication in patients with AD. Because medications to treat AD may preferentially improve gist memory or item-specific recollection, use of this type of paradigm may improve sensitivity for detection of drug effects more than standard memory tests.

AVP (4-8) improves concept learning in PFC-damaged but not hippocampal-damaged rats

A position reversal task was used to test the memory-enhancing effects of the arginine vasopressin analog [pGlu4, Cyt6] AVP (4-8) at a dose of 1.5 microg/kg. Rats received either sham operations (SHM), medial prefrontal cortex lesions (PFC), or hippocampal lesions (HIP). The peptide was administered daily, via s.c. injection, 30 min prior to training to half of the animals in each group. As expected, all animals performed equally well on the initial position habit and the first reversal. Overall, it was found that AVP (4-8)-treated animals performed significantly better across trials than saline (SAL)-treated animals. Further analysis showed that PFC animals that received AVP (4-8) (PFC+AVP) performed significantly better (at the level of controls) across trials than saline-treated PFC (PFC+SAL) animals. Sham animals that received the AVP (4-8) analog (SHM+AVP) only showed significant improvement on the last two reversals when compared to the sham saline-treated animals (SHM+SAL), which was likely due to a ceiling effect as performance reached high levels early in the reversal task. Trial 2 analysis across reversals revealed enhanced cognitive abilities in both sham groups (SHM+SAL, SHM+AVP) and the PFC+AVP group, but not in the PFC+SAL, HIP+AVP or the HIP+SAL groups. Hippocampal lesioned animals performed poorly on the task and injections of AVP (4-8) did not improve their performance. It is thus concluded that AVP (4-8) enhanced the acquisition of concept learning (win-stay/loose-shift) in this paradigm in PFC-damaged animals and ameliorated the perseverance habit that is often seen in PFC animals on this task. It is suggested that AVP (4-8) might have an enhancing effect on general cognitive abilities that is not limited to memory processes.

Midazolam amnesia and conceptual processing in implicit memory

Prominent theories of implicit memory (D. Schacter, B. Church, & J. Treadwell, 1994) emphasize the dominant role of perceptual processing in mediating priming on perceptual implicit memory tests. Examinations of the effects of conceptual processing on perceptual implicit memory tests have produced ambiguous results. Although a number of investigations (e.g., J. Toth & R. Hunt, 1990) have demonstrated that variations in conceptual processing affect priming on perceptual implicit memory tests, these effects may arise because of the contaminating effects of explicit memory. The current experiment examined this controversy using midazolam, a benzodiazepine that produces a dense, albeit temporary, anterograde amnesia when injected prior to study. The experiment examined whether the effects of generation found on the implicit memory test of perceptual identification were affected by a midazolam injection prior to study. Results demonstrated that midazolam substantially diminished generation effects in free and cued recall, as well as overall performance on these tests, but had no detectable effect on the generation effect in perceptual identification.

The effects of acutely administered low dose sarin on cognitive behaviour and the electroencephalogram in the common marmoset

Previous studies have suggested that administration of a clinically sign-free dose of sarin to non-human primates gives rise to subtle changes in brain electrical activity as measured by electroencephalography (EEG) several months following exposure. The functional significances of such changes are unclear. The present study monitored EEG by using implantable radiotelemetry, and also assessed the performance of complex behavioural tasks, in non-human primates for up to 15 months following exposure to a low dose of sarin. Baselines of EEG and behaviour were shown to be stable over several months in control animals. The doses of sarin administered caused erythrocyte cholinesterase inhibitions of 36.4% to 67.1%. Overall, no significant changes in EEG patterns were observed although there were increases in beta 2 amplitude which approached significance (p=0.07). No deleterious effects on performance were seen on the touchscreen mediated discrimination tasks presented from the Cambridge Neuropsychological Test Automated Battery (CANTAB). This study illustrates the validity of the approach employed and makes an important contribution to the investigation of the long-term effects of organophosphorous compounds.

Relation between executive cognitive functioning and the adverse consequences of alcohol use in social drinkers

The purpose of this study was to assess the relation between Executive Cognitive Functioning (ECF) and the adverse consequences of alcohol consumption. ECF encompasses "higher order" cognitive abilities involved in goal-directed behavior, such as attentional control, mental flexibility, planning, and self-monitoring. Impaired ECF has been shown to result in a variety of negative consequences, including excessive drug and alcohol use. Subjects were 79 nonalcoholic male social drinkers between 17 to 30 years of age. ECF was measured using three neuropsychological tests: the Wisconsin Card Sorting Test (WCST), the Conditional Associative Learning Test (CAT), and the Sequential Matching Memory Test (SMMT). Adverse drinking consequences were measured using the Drinker Inventory of Consequences (DrInC). The DrInC assesses drinking consequences in five domains: Physical, Intrapersonal, Interpersonal, Social Responsibility, and Impulse Control. Scores from the neuropsychological tests were reduced into two latent variables: one representing the WCST and the other representing the CAT and SMMT. The results indicated that errors on the CAT/SMMT variable were positively related to adverse consequences in each domain, except for physical consequences. A similar association was found between the WCST variable and impulse control consequences. These findings indicate that performance on tests measuring ECF is related to the severity of drinking consequences. Therefore, prevention and treatment outcomes may be improved by incorporating cognitive habilitation into current interventions.

Language comprehension in schizophrenia: trait or state indicator?

Language comprehension, measured by the Luria-Nebraska Relational Concepts Factor Scale, was evaluated twice in 15 male DSM-III-R schizophrenic patients during a controlled double-blind haloperidol maintenance (without anticholinergics) and placebo replacement protocol. Fifteen male normal controls were tested once. Patients and controls were matched on age and education. Language comprehension was significantly reduced in patients under both pharmacologic conditions, as compared with controls. Patients' comprehension accuracy did not differ significantly between neuroleptic-treatment and placebo replacement conditions. Patients' comprehension accuracy was independent of positive symptoms, anxiety-depression, measures of clinical course, and CSF and plasma monoamines. Comprehension accuracy was also not associated with patients' educational level or WAIS-R measures of their intellectual and short-term memory functioning. Patients' comprehension performance was significantly associated only with the negative symptom anhedonia-asociality during haloperidol maintenance. Thus, language comprehension in schizophrenic patients was independent of changes in pharmacologic treatment and the positive symptoms of psychosis. Results suggest language comprehension may represent a stable or trait characteristic in schizophrenia.

Abstracting capacity in cirrhotic alcoholics: negative findings

OBJECTIVE

Alcoholic and nonalcoholic cirrhotics and normal controls were compared to determine the extent to which the cognitive deficits frequently observed in alcoholics are attributable to hepatic encephalopathy.

METHOD

A battery of neuropsychological tests was administered measuring verbal and nonverbal abstracting capacity.

RESULTS

No significant differences between the three groups were observed. Both the alcoholic (n = 43) and nonalcoholic (n = 63) subjects performed comparably to normal controls (n = 21) and the former two groups performed comparably to each other on seven indicators of abstracting capacity.

CONCLUSIONS

Deficits in reasoning ability are not invariably associated with chronic alcoholism. In addition, low grade hepatic encephalopathy concomitant to cirrhosis in both alcoholics and nonalcoholics does not impact adversely on abstracting capacity.

Impaired problem solving in Parkinson's disease: impact of a set-shifting deficit

Parkinson's disease (PD) is associated with specific cognitive deficits in the absence of dementia, including the inability to suppress previously learned responses in a changed context. Our goal was to determine whether this set-shifting deficit is sufficient to account for impaired performance on a problem-solving task, or, instead, whether it is necessary to postulate deficits in one or more other cognitive capacities, such as logical deduction. Deductive reasoning and other conceptual abilities were assessed in 15 nondemented subjects with PD who had never been medicated, 15 nondemented subjects with PD who were currently receiving medication, and 15 healthy elderly control subjects. On a deductive reasoning task, Poisoned Food Problems, the PD groups made more errors than the control group. The PD groups' error pattern was characterized by intrusions of information from previous problems. By contrast, the PD groups made appropriate assessments of redundant and irrelevant information that appeared in these problems, and performed normally on other tests of concept formation and problem solving that did not require set shifting, indicating that the capacities for logical deduction and concept formation were intact. The set-shifting deficit, conceptualized as a difficulty in suppressing a prepotent response, appears to be a primary cognitive impairment in PD and presumably arises from dysfunction of the nigrostriatal-dorsolateral prefrontal cortex complex loop.

Problem-solving deficits in alcoholics: evidence from the California Card Sorting Test

In an attempt to clarify the nature of the problem-solving deficits exhibited by chronic alcoholics, the California Card Sorting Test (CCST) and other measures of abstraction and problem solving were administered to 23 alcoholics and 16 nonalcoholic controls, equated for age, education and vocabulary. On the CCST, the alcoholics exhibited three types of deficits which appeared to be relatively independent. First, the alcoholics generated and identified fewer correct concepts than controls, although they executed concepts normally when cued by the examiner. Second, the alcoholics made more perseverative sorting responses and perseverative verbal explanations for their sorting behavior than did controls. Third, alcoholics provided less complete verbal explanations of the concepts that they correctly generated or identified. The differential importance of these factors on various measures of problem solving may help to explain the varied patterns of inefficient problem solving exhibited by alcoholics.

Question-asking strategies in abstinent alcoholics: a study of learning potential

The question-asking strategies of 90 Finnish alcoholics were measured on a Vygotskian version of the Twenty Questions procedure. There were two questions to analyse: (1) can the performance of alcoholics be improved by means of instruction in question-asking; and (2) how does the duration of abstinence affect test performance? The results indicated that instruction had a positive effect on the performance of alcoholics. The duration of abstinence had no general effect; its effect was evident only in one type of question, i.e., pseudoconstraint questions. There were marked interindividual differences in both the pre-test and the post-test. About 15% of the subjects showed no noticeable improvement in their post-test performance in spite of the instruction they received.

Neuropsychological deficits in abstinent cocaine abusers: preliminary findings after two weeks of abstinence

Sixteen subjects hospitalized for treatment of cocaine dependence were administered a battery of neuropsychological tests within 72 h of last cocaine use and again approximately 2 weeks later. Twenty-one non-cocaine using control subjects, matched for age, gender, ethnicity and education, also received neuropsychological testing. Abstinence from mood altering substances during the 2-week study period was verified for both groups on three occasions using quantitative urine analysis. The results suggest that recent cocaine use is associated with impairment in memory, visuospatial abilities, and concentration during the acute phase of withdrawal, independent of withdrawal-related depression. Furthermore, many of these deficits appear to persist at least 2 weeks beyond cessation of cocaine use.

Effects of chronic marijuana use on human cognition

Impairments of human cognition and learning following chronic marijuana use are of serious concern, but have not been clearly demonstrated. To determine whether such impairments occurred, this study compared performance of adult marijuana users and non-users (N = 144 and N = 72, respectively) matched on intellectual functioning before the onset of drug use, i.e., on scores from standardized tests administered during the fourth grade of grammar school (Iowa Tests of Basic Skills). Subjects were given the twelfth grade versions of these tests (Iowa Tests of Educational Development) and other, computerized cognitive tests in successive test sessions. "Heavy" marijuana use (defined by use seven or more times weekly) was associated with deficits in mathematical skills and verbal expression in the Iowa Tests of Educational Development and selective impairments in memory retrieval processes in Buschke's Test. The retrieval impairments were restricted to words that were easy to visualize. Impairments depended on the frequency of chronic marijuana use, i.e., "light" and "intermediate" marijuana use (defined by use one to four and five to six times weekly, respectively) were not associated with deficits. Intermediate use was associated with superior performance in one condition ("fuzzy" concepts) of a Concept Formation test.

Future time perspective in current and previous injecting drug users

Future time perspective (FTP) is a measure of an individual's ability to conceptualise the future which has been shown to be foreshortened in drug addicts. We studied 100 opiate injecting drug users (IDUs) in New South Wales, Australia, of which half were currently injecting and half were not. There was a significant difference between the two groups on FTP, with those currently injecting having a truncated FTP extension. Factor analysis of the FTP scale suggested that the dimensions of future time may differ between groups, with current injectors having a perspective of loss and isolation compared to the dimension of self-evaluation and self-acceptance in those not currently injecting. These data support previous studies which demonstrated truncated FTP, also demonstrating a difference in currently (as opposed to previously) IDUs and suggest that both extension of FTP and an alteration of the dimensions of FTP are associated with cessation of injecting and entry into treatment.

Acute effects of marijuana on cognition: relationships to chronic effects and smoking techniques

A double-blind, placebo-controlled study assessed acute effects on human cognition of marijuana smoking involving long or short durations of inhalation and breath holding. During eight test sessions, 48 adult, male volunteers completed standardized, pencil-and-paper tests of educational development and ability, as well as computerized tests of learning, associative processes, abstraction, and psychomotor performance. Marijuana impaired all capabilities except abstraction and vocabulary. These impairments were more pervasive than those associated with heavy, chronic marijuana use in a previous study involving the same tests, but showed some similarities. Marijuana altered associative processes, encouraging more uncommon associations. Marijuana-induced impairment in learning pairs of words was influenced by associative relationships between the words. There were a few hints that prolonged breath holding increased marijuana's effects under some test conditions, but in general it did not. Prolonged breath holding itself affected performance in four tests, regardless of whether subjects smoked marijuana or placebo. Whether physiological or psychological factors (e.g., exposure to carbon monoxide in smoke or subjects' expectations) produced these effects could not be determined.

Methylphenidate and cognitive perseveration in hyperactive children

Effects of methylphenidate on cognitive flexibility were investigated in 26 children with Attention Deficit Hyperactivity Disorder (ADHD), by assessing perseverative errors on the Wisconsin Card Sorting Test (WCST) and the emergence of clinical symptoms indicative of cognitive perseveration. A double-blind, placebo-control, randomized crossover design was used in which each child was assessed twice in each drug condition (placebo, 0.3 and 1.0 mg/kg). Results indicated that methylphenidate increased perseverative errors on the first assessment but decreased them on the second; clinical symptoms of perseveration occurred at both assessments. Findings suggest that MPH may reduce cognitive flexibility temporarily in some ADHD children.

Systolic blood pressure and neuropsychological test performance of alcoholics

This study examined resting systolic blood pressure (SBP) as a mediator of neuropsychological (NP) test performance in nonhypertensive alcoholics and controls. A median-split was used to assign alcoholics and controls to low and high SBP groups. Results showed that: (1) When SBP level was not considered, alcoholics only performed worse than controls on the WAIS Comprehension subtest. (2) Alcoholics and controls in the high SBP groups had fewer correct items on the WAIS Comprehension and Raven's, Set I tests than subjects in the low SBP groups. (3) Significant Diagnostic Group by SBP Group interaction was found for the Sentence Writing test. For this test only controls in the High SBP Group did worse than controls in the Low SBP Group. (4) Individual group comparisons for all NP tests showed that alcoholics in the High SBP Group were more impaired than controls in the Low SBP Group on the WAIS Comprehension, Shipley Abstraction Age and Stark Visual-Spatial tests; but alcoholics in the Low SBP Group did not differ from, or outperformed, controls in the High SBP Group on the WAIS Comprehension, Shipley Abstraction Age, Raven's, Set I, and Stark Visual-Spatial tests. These data demonstrate that both alcoholism and high SBP adversely and differentially affect the NP test performance of alcoholics and controls.

Measuring the learning potential of abstinent alcoholics

The performance of 89 Finnish alcoholics was measured on a Vygotskian test of learning potential. There were four questions to analyse: (1) can the performance of alcoholics be improved by means of instruction in non-verbal problem solving tasks; (2) how extensive is the transfer effect; (3) how does the duration of abstinence affect test performance; and (4) how does the actual performance level affect post-test results? Results indicated that instruction had a clear positive effect on the performance of alcoholics in simple tasks, but no transfer effect was evident in the more complex tasks. The duration of abstinence had no general effect. Although analysis of the mean scores of time-level groups showed some improvement in performance with increasing duration of abstinence, intra-group deviation was so high that the trends were not statistically significant. The subjects' actual performance level, on the other hand, was a very relevant factor. This was particularly evident in complex transfer tasks.

The specificity of the effects of stimulant medication on classroom learning-related measures of cognitive processing for attention deficit disorder children

There appear to be beneficial effects of stimulant medication on daily classroom measures of cognitive functioning for Attention Deficit Disorder (ADD) children, but the specificity and origin of such effects is unclear. Consistent with previous results, 0.3 mg/kg methylphenidate improved ADD children's performance on a classroom reading comprehension measure. Using the Posner letting-matching task and four additional measures of phonological processing, we attempted to isolate the effects of methylphenidate to parameter estimates of (a) selective attention, (b) the basic cognitive process of retrieving name codes from permanent memory, and (c) a constant term that represented nonspecific aspects of information processing. Responses to the letter-matching stimuli were faster and more accurate with medication compared to placebo. The improvement in performance was isolated to the parameter estimate that reflected nonspecific aspects of information processing. A lack of medication effect on the other measures of phonological processing supported the Posner task findings in indicating that methylphenidate appears to exert beneficial effects on academic processing through general rather than specific aspects of information processing.

Cognitive impairment in alcoholics

The research literature shows that, as a result of chronic alcohol abuse, there occur impairments in abstract reasoning, problem-solving, and perceptual-motor functioning. In an earlier study, Tamkin (1983) obtained significant differences between alcoholics and paired neurotic inpatient controls only on abstract reasoning measured on the Weigl Color-Form Sorting Test. Verbal functions and recall of designs showed no group differences. This study sought to replicate the Weigl test results and to examine other types of cognitive impairments in alcoholics relative to published norms. The study subjects were 104 male alcoholics in an alcohol rehabilitation unit. The tests used were the Weigl, Trails A and B, and three subtests of the WAIS. The proportion of impaired Weigl performances was similar to that obtained in 1983, and all the other test scores were significantly poorer than their published norms.

The effects of repeating a recognition test in lorazepam-induced amnesia: evidence for impaired contextual memory as a cause of amnesia

In two experiments, a recognition test for an earlier presented list was given twice in immediate succession (Test 1 and Test 2). On the hypothesis that anterograde amnesia for episodic memory involves a deficit in contextual memory, amnesic subjects should confuse familiarity with distractor items gained during Test 1 with familiarity gained during original list presentation. As a result, they should think that they recognize more items on Test 2. This will lower recognition efficiency in Test 2 by increasing false alarms rather than by reducing hits. For subjects with an amnesia induced by lorazepam, but not for control subjects, recognition efficiency was substantially reduced in Test 2 in both experiments. As predicted, this impairment was due to a large increase in false alarms, with no decrease in the number of hits. The impairment could not be explained by a difference in recognition level between lorazepam and control subjects on Test 1. These findings therefore support the contextual memory deficit hypothesis of anterograde amnesia. Their implications for understanding the relationship between recall and recognition in amnesia are discussed.

Reduced performance in tests of memory and visual abstraction in seamen exposed to industrial solvents

Eighty-five seamen exposed to a variety of organic solvents and hydrocarbon compounds during their work on chemical tankers were compared with 59 unexposed seamen. Visual memory, auditory memory and visual abstraction were examined 14 days or more after the last solvent exposure. Multivariate analyses were performed to control the effects of confounding factors such as age, alcohol consumption, smoking, cerebral concussions and educational level. Significant correlations were found between increasing solvent exposure and poor results in tests of auditory memory and visual abstraction. These results indicate adverse psychological effects caused by chronic organic solvent exposure.

Analogical reasoning abilities of recovering alcoholics

This study investigated analogical reasoning abilities of alcoholics who had been abstinent from alcohol for at least 1 year. Their performance was compared to that of nonalcoholic controls matched as a group for education, age, and gender. Solution times and error rates were modeled using a regression model. Results showed a nonsignificant trend for alcoholics to be faster, but more error prone, than controls. The same componential model applied to both groups, and fit them equally well. Although differences have been found in analogical reasoning ability between controls and alcoholics immediately following detoxification, we find no evidence of differences after extended periods of sobriety.

The effects of methylphenidate on learning in children with ADDH: the stimulus equivalence paradigm

Investigated the effect of methylphenidate (MPH) on the ability of children with Attention Deficit Disorder with Hyperactivity (ADDH) to learn both trained and untrained complex visual relationships and compared these findings to their school performance under identical dosage parameters. 26 children between the ages of 6 and 12 years with ADDH participated in a double-blind, placebo control, within-subjects design in which each child received four doses of MPH (5, 10, 15, 20 mg) and a placebo in a counterbalanced sequence. MPH enhanced children's learning of both taught and untaught visual relationships, and most changes were similar to, albeit less dramatic than, those obtained for the children's attention and academic performance in school. Results of group and single-subject analyses are presented and discussed with relevance to psychopharmacological research and understanding the complex relationship between learning and psychostimulants used in treating children with ADDH.

Defective concept formation in parkinsonians is independent from mental deterioration

An extensive neuropsychological battery (the Mental Deterioration Battery) was utilized to distinguish, within a sample of 24 idiopathic Parkinsonians, those showing signs of diffuse mental deterioration (n = 9) from those without deterioration (n = 15). Performances of control subjects on a wide range of tests exploring mnesic, visuo-constructive, linguistic and general intellectual functions (n = 21) did not differ from analogous performances of Parkinsonians without signs of diffuse mental deterioration. The Wisconsin Card Sorting Test was then used to verify the hypothesis that a selective impairment of cognitive functions subsumed by the integrity of frontal lobes could be demonstrated in Parkinsonian patients. Our results provide evidence that in this task, defective performances are obtained by Parkinsonians and even by patients without signs of diffuse cognitive impairment. These findings seem to confirm that a deficit in concept formation, maintenance and shifting is largely independent of the dementia frequently noticed in Parkinson's disease.

Effects of diazepam on a belief-updating task

This study examined the effects of a minor tranquilizer, diazepam, on a cognitive task that involved the updating of beliefs. On this task, subjects are first asked to express their strength of belief in a hypothesis and then to update this on the basis of new evidence. Past research has shown that revision of beliefs can be affected by many variables including the strength with which the initial belief is held, whether new information is perceived as positive or negative vis-à-vis the hypothesis, and the order in which evidence is processed. The purpose of this study was to assess whether a tranquilizer, diazepam, would affect the updating of beliefs, and specifically whether it would dampen the extent to which people revise their opinions. 12 healthy subjects participated in four experimental sessions, in which they received diazepam (0.14 mg/kg) or placebo and completed an updating task in which they received information in either of two orders, positive-negative or negative-positive. In each session, subjects saw a different experimental stimulus determined by a Latin-square design, and also completed pre- and postdrug mood questionnaires. Analysis showed order of presentation induced a recency effect similar to that obtained in previous studies, and the diazepam produced significant tranquilizer-like effects on self-report questionnaires. However, the diazepam had no effect on the updating task. These findings indicate that previously reported order effects in the belief updating task are robust and unaffected by a drug that has known sedative and memory-impairing properties.

Abstracting deficits and childhood conduct disorder as a function of familial alcoholism

Using a large sample (n = 515), family history-positive male alcoholics (FH+) performed poorer than family history-negative (FH-) alcoholics on a test of abstracting ability. They also reported an earlier age of onset of alcoholism, more symptoms of childhood conduct disorder, and tended to report more depressive symptoms than FH- alcoholics, however, these variables were not significantly related to abstracting score. FH+ and FH- samples did not differ on average amount of ethanol consumed per day, vocabulary, state anxiety, childhood attentional deficit disorder, and childhood learning disability. The significant differences found in this study between FH+ and FH- alcoholics were minimal. With such weak effects, the inconsistent findings in studies that have investigated differences between FH+ and FH- alcoholics are understandable.

Scopolamine-induced deficits in acquisition of a complex spatial learning

The role of scopolamine was studied in a complex spatial orientation task. The procedure involved an increasing difficulty of the task: at the pretraining stage a cue (box) was placed at the reinforcement spot and the animal could give a correct response by adopting either a cue-strategy or an orientation response (i.e., go to the arm on the right of a visual landmark). In the subsequent spatial training, the box was removed, so that the orientation response was the only correct one. Results show that scopolamine-injected animals are able to use a cue-strategy but are unable to acquire a spatial orientation strategy: this more complex task asks for more time and for more sustained attention. When the response is already partly acquired, scopolamine has less effect. The cholinergic system would thus be involved in the quality or even the complexity of the response rather than in the retention itself. Though a state-dependent effect may not be excluded, it by itself cannot explain the observed differences. Finally, an impairment of the maintenance of attention could be responsible for the deficits observed in the acquisition of the complex task.

Effects of flurazepam and triazolam on neuropsychological performance

A double-blind study examined the effects of a single dose of either triazolam or flurazepam on measures of concept formation, attention, concentration, and motor function, the morning following drug ingestion. Subjects were 53 healthy university students, screened for history of neurological or psychiatric illness. In comparison to placebo-treated controls, there was no difference in the effects on neuropsychological performance, although subjects who received flurazepam reported more side effects. It was concluded that although these drugs may produce side effects, single doses do not appear to impair various aspects of neuropsychological ability the morning after ingestion.

Cognitive effects of lithium carbonate and haloperidol in treatment-resistant aggressive children

The effects of lithium carbonate and haloperidol on cognition were examined in a placebo-controlled, double-blind study of 61 treatment-resistant, hospitalized school-aged children. They all had a DSM-III diagnosis of conduct disorder-- undersocialized , aggressive, with a profile of highly explosive and aggressive behavior. Children were assessed at the end of a two-week placebo-baseline period and again after four weeks of treatment. Drug effects on cognition were mild. Haloperidol (mean dose, 2.95 mg/day) caused significant decreases in Porteus Maze test quotient scores and a slowing of reaction time (RT) on a simple RT task. Lithium carbonate (mean dose, 1,166 mg/day) adversely affected qualitative scores on the Porteus Maze test. No significant treatment effects were found for the Matching Familiar Figures Test, short-term recognition memory and concept attainment tasks, or the Stroop Test.

Neuropsychological differences between male familial and nonfamilial alcoholics and nonalcoholics

The hypothesis was tested that neuropsychological differences exist between males who have an alcoholic parent, sister, or brother (FH+) versus those who do not (FH-). Neuropsychological tests measuring verbal, learning/memory, abstracting/problem solving, and perceptual-motor performance were given to four groups of middle-aged subjects: alcoholic FH+ (n = 41); alcoholic FH- (n = 27); nonalcoholic FH+ (n = 19); and nonalcoholic FH- (n = 43). FH+ subjects performed significantly poorer than FH- subjects on the abstracting/problem solving and perceptual-motor tasks, and approached significance on the verbal and learning/memory measures. Alcoholics performed more poorly than nonalcoholics on abstracting/problem solving and learning/memory tasks. There were no groups by family history significant interactions. From these results we suggest: a performance deficit in abstracting/problem solving and possibly learning/memory may antedate the alcoholic stage in FH+ individuals; alcoholism and positive family history of alcoholism have independent, additive deleterious effects on cognitive-perceptual functioning; and future neuropsychological studies of alcoholism should consider the frequency of FH+ and FH- individuals in both alcoholic and control groups.

A mode control model of counting and timing processes

The similarity of animal counting and timing processes was demonstrated in four experiments that used a psychophysical choice procedure. In Experiment 1, rats initially learned a discrimination between a two-cycle auditory signal of 2-sec duration and an eight-cycle auditory signal of 8-sec duration. For the number discrimination test, the number of cycles was varied, and the signal duration was held constant at an intermediate value. For the duration discrimination test, the signal duration was varied, and the number of cycles was held constant at an intermediate value. Rats were equally sensitive to a 4:1 ratio of counts (with duration controlled) and a 4:1 ratio of times (with number controlled). The point of subjective equality for the psychophysical functions that related response classification to signal value was near the geometric mean of the extreme values for both number and duration discriminations. Experiment 2 demonstrated that 1.5 mg/kg of methamphetamine administered intraperitoneally shifted the psychophysical functions for both number and duration leftward by approximately 10%. Experiment 3 demonstrated that the magnitude of cross-modal transfer from auditory signals to cutaneous signals was similar for number and duration. In Experiment 4 the mapping of number onto duration demonstrated that a count was approximately equal to 200 msec. The psychophysical functions for number and duration were fit with a scalar expectancy model with the same parameter values for each attribute. The conclusion was that the same internal mechanism is used for counting and timing. This mechanism can be used in several modes: the "event" mode for counting or the "run" and the "stop" modes for timing.

The role of occupational lead exposure in the genesis of psychiatric and behavioral disturbances

In a prospective study of lead neurotoxicity, exposed foundry workers and referents were evaluated using a comprehensive set of neurobehavioral tests. Other performance indexes were used including a questionnaire, physical examination, and nerve conduction testing. Results show increased rates of depression, confusion, anger, fatigue and tension among workers with blood levels over 40 mcg/dl. Other aspects of neurobehavioral function, including verbal concept formation, memory, and visual/motor performance were also impaired. In view of the large number of individuals exposed to lead in their work, specific inquiries should be made of individuals with affectual complaints to clarify the nature of their work and workplace exposure to lead.

Acquisition and retrieval of information in amphetamine-treated hyperactive children

State-dependent learning and memory (retrieval) processes were examined in 15 amphetamine-treated hyperactive boys. While stimulant treatment enhanced the acquisition of information and its retrieval 24 hours later, there was no evidence of poorer retrieval of information learned in a state different from the retrieval state. Amphetamine appeared particularly to facilitate effortful cognitive processes. Subgroups of hyperactive children respond to amphetamine treatment in different ways, some showing changes in motor restlessness and others changes in cognition. The lack of dissociative effects when information is learned and recalled under different drug conditions suggests that what the stimulant-treated child learns can be effectively recovered after completion of treatment.

Effects of chemicals on delayed matching behavior in pigeons I: acute effects of drugs

Pigeons were trained to peck a red or green center key 15 times to turn it off. After a delay, two side keys, one red and one green were illuminated. Pecks on the side key whose color matched the color that the center key had been produced food. Pecks on the other side key produced a timeout. The effects of various drugs were studied as the delay between extinguishing of the center key light and illumination of side keys was varied from 1 to 8 sec. Pentobarbital and phencyclidine consistently decreased matching, but morphine, d-amphetamine and delta 9-tetrahydrocannabinol had little effect on matching even at doses that increased latency to respond and decreased the rate of responding. Pentobarbital frequently decreased matching at doses below those that increased response latency and decreased response rate, but phencyclidine decreased matching only at doses that increased latencies and decreased rates. The effects of pentobarbital on matching did not depend on the delay duration.

The effects of clobazam and lorazepam on aspects of psychomotor performance and car handling ability

1 Laboratory tests of psychomotor performance and 'on road' assessments of car handling ability were made following repeated doses of clobazam 10 mg three times daily, lorazepam 1 mg three times daily and matching placebo 1 capsule three times daily. 2 Both active compounds produced on impairment, compared to placebo, in some mental arithmetic and letter cancellation tasks, but these effects were neither widespread nor consistent. 3 Lorazepam produced a significant impairment of car driving tasks and analogue rating scales of subjective alertness. The pronounced sedative activity of the drug was also shown in the verbal reports of side effects and in indices of early morning sedation derived from the Leeds Sleep Evaluation Questionnaire. 4 Clobazam did not produce either the objective, or the subjective impairment of performance and alertness found with lorazepam. 5 The results taken as a whole show important differences between the 1,4 benzodiazepine, lorazepam, and the 1,5 benzodiazepine, clobazam, in their effects on the integrity of psychomotor performance related to car driving ability.

Alcohol and the aging process in social drinkers

Social drinkers' performance on tests of abstracting and concept formation declined significantly as a function of age and of the quantity of alcohol consumed per drinking occasion.

Influences of an analog of the neuropeptide ACTH 4--9 on mentally retarded adults

In a double-blind procedure, 24 mentally retarded adults received 0 mg, 5mg, or 20 mg of an analog of the neuropeptide ACTH 4--9. Following treatment with peptide, the subjects were given the Trails B Test (from the Halstead-Reitan Neuropsychological Battery), the Peabody Picture Vocabulary test, the Benton Visual Retention Test, a concept-formation task, and a standard orienting sequence. The results of the behavioral tests suggested that attentional processes were enhanced in subjects treated with the peptide. The present study, in conjunction with another investigation using the neuropeptide ACTH/MSH 4--10 (Sandman, George, Walker, Nolan & Kastin, 1976), indicates that attentional deficits in mentally retarded adults, traditionally assumed to be irreversible, may be influenced by treatment with fragments of the neuropeptides ACTH and MSH.

Relationship between neuropsychological performance and alcohol consumption in alcoholics

Cognitive performance in drug-free alcoholic patients (n = 95) within 7 days of their last drink was significantly predicted by chronic and recent drinking practices. Conceptually distinct cognitive functions were differentially influenced by various combinations of drinking variables. Consideration of curvilinear relationships enhanced the amount of variance explained, and it is suggested that certain patterns of consumption may accelerate the alcohol-induced decline of brain function.

Parkinsonism: effects of levodopa treatment on concept formation

Concept formation was compared in 71 parkinsonian patients and 35 controls matched for age and WAIS vebal IQ. It was found that the patients formed significantly fewer concepts, as measured by the Wisconsin Card Sorting Test (WCST). The patients had difficulties in shifting sets and were unable to attend to the completion of a concept. Levodopa-treated patients were able to produce more correct responses, but were still unable to maintain the correct responses to produce more correct concepts than non-levodopa-treated patients. The behavior of the parkinsonian patients on the WCST is similar to that of patients who have undergone frontal lobectomy. In addition, the results indicate that levodopa therapy may improve "vigilance", without increasing the patient's overall cognitive ability.

Intellectual and neuropsychological functions in young men with heavy and long-term patterns of drug abuse

The authors attempted to determine the long-term effects of heavy drug abuse in 87 male prisoners. The sample was divided into the following groups: 1) nondrug users; 2) users of cannabis and hallucinogens; 3) users of cannabis, hallucinogens, and amphetamines; and 4) users of cannabis, hallucinogens, amphetamines, and opiates. Intellectual and neuropsychological tests sensitive to brain dysfunction revealed no intergroup differences. This finding casts some doubt on other reports suggesting that long-term drug abuse results in neuropsychological disorders. However, the authors caution that one should not conclude that no organic changes occurred in their sample.