Associations of Regular Marijuana Use by Adolescent Boys With Verbal Memory and Perseveration.

Many American and Dutch adolescents use marijuana regularly. There is concern that such use may impair cognitive function more in adolescents than adults. We examined effects of regular marijuana use on long-term memory and perseveration among American and Dutch adolescents. We administered Buschke's Selective Reminding Test (BSRT) to assess long-term memory and the Wisconsin Card Sorting Test (WCST) to assess perseveration in male teenagers. Usable test data were obtained for 12 American marijuana users, 13 American controls, 9 Dutch marijuana users, and 12 Dutch controls. In BSRT, users showed lower overall long-term storage than controls (adjusted means ± SE's for numbers of words per trial of 9.4 ± 0.2, 13.4 ± 0.3, 11.7 ± 0.2, and 12.4 ± 0.2 for American users, Dutch users, American controls, and Dutch controls, respectively). Marijuana was associated with memory effects only in American, not Dutch, users. Bivariate Pearson correlations for American and Dutch users combined showed associations of lower total recall with more uses in the previous year and lifetime (r = -0.61 and r = -0.53, respectively); and more perseverative errors with more uses in the previous year (r = 0.55). Some findings were consistent with the possibility that regular adolescent marijuana use causes deficits in cognition, especially memory. However, a causal interpretation cannot be inferred from our findings and is challenging to reconcile with the observation of memory deficits only in American users. Our study was novel in examining the influence of nationality on marijuana's cognitive effects. More studies of this topic should compare effects across nationalities or cultures.

Do Departments in a College of Medicine Differ in Academic Productivity As Assessed by the H-Indices of Tenured Faculty Members?

BACKGROUND: It is uncertain how different academic medical departments differ in academic productivity as assessed by commonly used bibliometric measures, eg, the h-index (the maximum value of h such that an author has published h papers that have each been cited at least h times). AIM: This project examined whether departments in the University of Iowa's Carver College of Medicine differed in h-indices of tenured faculty members. METHODS: Based on 2020 data obtained from the College (and other University sources), the author compiled three data sets of Scopus h-indices of tenured faculty members identified by department, varying in size due to slightly different inclusion criteria (N's=334, 341, and 354). Analyses compared h-indices between ranks and among departments. RESULTS: In the basic data set (N=334), h-indices of the 230 (69%) full and 104 (31%) associate professors differed based on a t-test, means (standard deviations)=37 (17) and 20 (7), respectively, p<0.0001. For both full and associate professors separately, departments differed in h-indices based on analyses of variance, p=0.04 and p=0.02, respectively. In the expanded data sets, departmental differences were significant for full and associate professors (with N=341) and full professors (with N=354). CONCLUSION: Departments differed in academic productivity of tenured faculty members as assessed by h-indices. This was not a powerful, monolithic effect, ie, relative departmental standings for full and associate professors were not consistent, and departmental differences for associate professors were nonsignificant in the largest (N=354) data set. Multiple factors probably contributed to departmental differences and should be further investigated.

Is Exhaustion More Sensitive Than Disengagement to Burnout in Academic Anesthesia? A Study Using the Oldenburg Burnout Inventory.

Reportedly, clinicians of all kinds are experiencing alarming rates of burnout, and its prevalence among anesthesia providers is high. We examined burnout in a large academic anesthesia department with a commonly used questionnaire, the Oldenburg Burnout Inventory, which provides scores on two scales, "exhaustion" and "disengagement." We examined differences in scores between exhaustion and disengagement and their prevalences. All N = 415 staff members of the department were requested to complete the Oldenburg Burnout Inventory and N = 130 (31%) did so. The mean ± standard deviation was 2.52 ± 0.51 (range, 1.13 to 3.75) for exhaustion and 2.27 ± 0.52 (range, 1.13 to 3.63) for disengagement. The mean for exhaustion exceeded that for disengagement by 0.25 ± 0.42 (range, -1.25 to 1.25), t(129)=6.68, p < 0.0001 by paired t test. Mean ratings exceeded the midpoint (2.5) between the "burned out" and "not burned out" ends of the rating scale for 49% of respondents for exhaustion, but only 30% for disengagement. More respondents (N = 87, 67%) had a higher mean for exhaustion than disengagement than the opposite pattern (N = 28, 22%), M = 29.5, p < 0.0001 by sign test. Thus, burnout symptoms were common but reflected more in exhaustion than disengagement. Literature review suggested that the difference between the exhaustion and disengagement means that we found was larger than typical, but not unusual, for health-care-related groups, and typical for other groups. Future studies should clarify circumstances under which exhaustion exceeds disengagement and vice versa, both in anesthesia and other fields.

Are Anesthesia and Surgery during Infancy Associated with Decreased White Matter Integrity and Volume during Childhood?

BACKGROUND: Anesthetics have neurotoxic effects in neonatal animals. Relevant human evidence is limited. We sought such evidence in a structural neuroimaging study. METHODS: Two groups of children underwent structural magnetic resonance imaging: patients who, during infancy, had one of four operations commonly performed in otherwise healthy children and comparable, nonexposed control subjects. Total and regional brain tissue composition and volume, as well as regional indicators of white matter integrity (fractional anisotropy and mean diffusivity), were analyzed. RESULTS: Analyses included 17 patients, without potential confounding central nervous system problems or risk factors, who had general anesthesia and surgery during infancy and 17 control subjects (age ranges, 12.3 to 15.2 yr and 12.6 to 15.1 yr, respectively). Whole brain white matter volume, as a percentage of total intracranial volume, was lower for the exposed than the nonexposed group, 37.3 ± 0.4% and 38.9 ± 0.4% (least squares mean ± SE), respectively, a difference of 1.5 percentage points (95% CI, 0.3 to 2.8; P = 0.016). Corresponding decreases were statistically significant for parietal and occipital lobes, infratentorium, and brainstem separately. White matter integrity was lower for the exposed than the nonexposed group in superior cerebellar peduncle, cerebral peduncle, external capsule, cingulum (cingulate gyrus), and fornix (cres) and/or stria terminalis. The groups did not differ in total intracranial, gray matter, and cerebrospinal fluid volumes. CONCLUSIONS: Children who had anesthesia and surgery during infancy showed broadly distributed, decreased white matter integrity and volume. Although the findings may be related to anesthesia and surgery during infancy, other explanations are possible.

The Relationship of Exposure to Anesthesia on Outcomes in Children With Isolated Oral Clefts.

This study evaluated the relationship between exposure to anesthesia and previously identified differences in cognitive functioning, growth, and volumetric brain measures among a sample of children, adolescents, and young adults with isolated oral clefts. Data from a cross-sectional study were combined with a retrospective chart review. Data were obtained for 87 participants with isolated cleft lip and/or palate (55% male), ranging from 7.5 to 27 years old (mean = 15.78, standard deviation = 4.58). Measures of interest included cognitive functioning, growth measures, and brain volumes. Number of surgeries and time under anesthesia were obtained through systematic medical record review. Potential sex and cleft type differences in exposure as well as relationships between anesthesia exposure and outcome measures were evaluated. Participants with isolated cleft lip and palate had more surgeries and were under anesthesia longer. For participants with isolated cleft lip only, more surgeries were correlated to lower verbal IQ and higher frontal lobe volume.

Anesthesia and the developing brain.

Despite the profound evolution in the safety and efficacy of neonatal and pediatric anesthesia, questions remain concerning the long-term neurotoxic and neurocognitive effects of the drugs used in anesthetic care. A variety of prospective animal models and retrospective human studies exist that inconsistently demonstrate a detrimental effect of early life exposure to anesthetic drugs and subsequent learning performance. Limitations associated with both non-human and human observational studies are critiqued. Research currently underway is briefly described. A framework for discussing the relevant issues with concerned parents is presented.

Tentative evidence for striatal hyperactivity in adolescent cannabis-using boys: a cross-sectional multicenter fMRI study.

Adolescents' risk-taking behavior has been linked to a maturational imbalance between reward ("go") and inhibitory-control ("stop")-related brain circuitry. This may drive adolescent drug-taking, such as cannabis use. In this study, we assessed the non-acute effects of adolescent cannabis use on reward-related brain function. We performed a two-site (United States and Netherlands; pooled data) functional magnetic resonance imaging (fMRI) study with a cross-sectional design. Twenty-one abstinent but frequent cannabis-using boys were compared with 24 non-using peers on reward-related brain function, using a monetary incentive delay task with fMRI. Focus was on anticipatory and response stages of reward and brain areas critically involved in reward processing like the striatum. Performance in users was normal. Region-of-interest analysis indicated striatal hyperactivity during anticipatory stages of reward in users. Intriguingly, this effect was most pronounced during non-rewarding events. Striatal hyperactivity in adolescent cannabis users may signify an overly sensitive motivational brain circuitry. Frequent cannabis use during adolescence may induce diminished ability to disengage the motivational circuit when no reward can be obtained. This could strengthen the search for reinforcements like drugs of abuse, even when facing the negative (non-rewarding) consequences.

Neural sensitivity to absolute and relative anticipated reward in adolescents.

Adolescence is associated with a dramatic increase in risky and impulsive behaviors that have been attributed to developmental differences in neural processing of rewards. In the present study, we sought to identify age differences in anticipation of absolute and relative rewards. To do so, we modified a commonly used monetary incentive delay (MID) task in order to examine brain activity to relative anticipated reward value (neural sensitivity to the value of a reward as a function of other available rewards). This design also made it possible to examine developmental differences in brain activation to absolute anticipated reward magnitude (the degree to which neural activity increases with increasing reward magnitude). While undergoing fMRI, 18 adolescents and 18 adult participants were presented with cues associated with different reward magnitudes. After the cue, participants responded to a target to win money on that trial. Presentation of cues was blocked such that two reward cues associated with $.20, $1.00, or $5.00 were in play on a given block. Thus, the relative value of the $1.00 reward varied depending on whether it was paired with a smaller or larger reward. Reflecting age differences in neural responses to relative anticipated reward (i.e., reference dependent processing), adults, but not adolescents, demonstrated greater activity to a $1 reward when it was the larger of the two available rewards. Adults also demonstrated a more linear increase in ventral striatal activity as a function of increasing absolute reward magnitude compared to adolescents. Additionally, reduced ventral striatal sensitivity to absolute anticipated reward (i.e., the difference in activity to medium versus small rewards) correlated with higher levels of trait Impulsivity. Thus, ventral striatal activity in anticipation of absolute and relative rewards develops with age. Absolute reward processing is also linked to individual differences in Impulsivity.

Clinical, methodological and theoretical issues in the assessment of cognition after anaesthesia and surgery: a review.

As people live longer, the burden of cognitive impairment to elderly patients, their families and society becomes increasingly common and important. The loss of independence, a reduction in the quality of life and increased mortality are possible correlates to the mental disintegration. Cognitive dysfunction following major surgery on the elderly is a significant problem which adds to other cognitive impairments caused by neurodegeneration, cerebrovascular impairments and other causes. There are challenges in reviewing the literature because of many methodological concerns. There is no standard definition; the diagnosis is made only by the results of neuropsychological tests which are not standardised for this purpose; test results are analysed by different statistical methods (some of them inappropriate); controls are often absent or poorly matched; and pre-existing mild cognitive impairment, which affects 10 to 20% of people older than 65 years and is similar to the subtle cognitive impairment following surgery, is not sought for and recognised. Reviews of the subject have varied from descriptions such as 'a well recognised and significant problem' to 'a hypothetical phenomenon for which there is no International Statistical Classification of Disease (ICD-9) code, and no Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) code'. This article examines both sides of the spectrum in a detailed review which explains the necessary psychological 'jargon', discusses the methods used and points to areas of future research.

Are anesthesia and surgery during infancy associated with altered academic performance during childhood?

BACKGROUND: Although studies in neonatal animals show that anesthetics have neurotoxic effects, relevant human evidence is limited. We examined whether children who had surgery during infancy showed deficits in academic achievement. METHODS: We attempted to contact parents of 577 children who, during infancy, had one of three operations typically performed in otherwise healthy children. We compared scores on academic achievement tests with population norms. RESULTS: Composite scores were available for 287 patients. The mean normal curve equivalent score was 43.0±22.4 (mean±SD), lower than the expected normative value of 50, P<0.0001 by one-sample Student t test; and 35 (12%) had scores below the 5th percentile, more than expected, P<0.00001 by binomial test. Of 133 patients who consented to participate so that their scores could be examined in relation to their medical records, the mean score was 45.9±22.9, P=0.0411; and 15 (11%) scored below the 5th percentile, P=0.0039. Of 58 patients whose medical records showed no central nervous system problems/potential risk factors during infancy, 8 (14%) scored below the 5th percentile, P=0.008; however, the mean score, 47.6±23.4, was not significantly lower than expected, P=0.441. Duration of anesthesia and surgery correlated negatively with scores (r=-0.34, N=58, P=0.0101). CONCLUSIONS: Although the findings are consistent with possible adverse effects of anesthesia and surgery during infancy on subsequent academic achievement, other explanations are possible and further investigations are needed.

Effects of chronic marijuana use on brain activity during monetary decision-making.

Marijuana (MJ) acutely acts on cannabinoid receptors that are found in numerous brain regions, including those involved in reward processing and decision-making. However, it remains unclear how long-term, chronic MJ use alters reward-based decision-making. In the present study, using [(15)O]water PET imaging, we measured brain activity in chronic MJ users, who underwent monitored abstinence from MJ for approximately 24 h before imaging, and control participants, while they took part in the Iowa Gambling Task (IGT), a monetary decision making task that strongly relies on the ventromedial prefrontal cortex (vmPFC). During PET imaging, participants took part in the standard and a variant version of the IGT as well as a control task. Chronic MJ users performed equally well on the standard IGT, but significantly worse than controls on the variant IGT. Chronic MJ users and control subjects showed increased regional cerebral blood flow (rCBF) in the vmPFC on both versions of the IGT compared to the control task. In the two-group comparison, chronic MJ users showed significantly greater rCBF than controls in the vmPFC on the standard IGT and greater activity in the cerebellum on both versions of the IGT. Furthermore, duration of use, but not age of first use, was associated with greater activity in the vmPFC. Thus, chronic MJ users tend to strongly recruit neural circuitry involved in decision-making and reward processing (vmPFC), and probabilistic learning (cerebellum) when performing the IGT.

Cannabis use and memory brain function in adolescent boys: a cross-sectional multicenter functional magnetic resonance imaging study.

OBJECTIVE: Early-onset cannabis use has been associated with later use/abuse, mental health problems (psychosis, depression), and abnormal development of cognition and brain function. During adolescence, ongoing neurodevelopmental maturation and experience shape the neural circuitry underlying complex cognitive functions such as memory and executive control. Prefrontal and temporal regions are critically involved in these functions. Maturational processes leave these brain areas prone to the potentially harmful effects of cannabis use. METHOD: We performed a two-site (United States and The Netherlands; pooled data) functional magnetic resonance imaging (MRI) study with a cross-sectional design, investigating the effects of adolescent cannabis use on working memory (WM) and associative memory (AM) brain function in 21 abstinent but frequent cannabis-using boys (13-19) years of age and compared them with 24 nonusing peers. Brain activity during WM was assessed before and after rule-based learning (automatization). AM was assessed using a pictorial hippocampal-dependent memory task. RESULTS: Cannabis users performed normally on both memory tasks. During WM assessment, cannabis users showed excessive activity in prefrontal regions when a task was novel, whereas automatization of the task reduced activity to the same level in users and controls. No effect of cannabis use on AM-related brain function was found. CONCLUSIONS: In adolescent cannabis users, the WM system was overactive during a novel task, suggesting functional compensation. Inefficient WM recruitment was not related to a failure in automatization but became evident when processing continuously changing information. The results seem to confirm the vulnerability of still developing frontal lobe functioning for early-onset cannabis use.

Sex differences in the effects of marijuana on simulated driving performance.

In the United States, one in six teenagers has driven under the influence of marijuana. Driving under the influence of marijuana and alcohol is equally prevalent, despite the fact that marijuana use is less common than alcohol use. Much of the research examining the effects of marijuana on driving performance was conducted in the 1970s and led to equivocal findings. During that time, few studies included women and driving simulators were rudimentary. Further, the potency of marijuana commonly used recreationally has increased. This study examined sex differences in the acute effects of marijuana on driving performance using a realistic, validated driving simulator. Eighty-five subjects (n = 50 males, 35 females) participated in this between-subjects, double-blind, placebo controlled study. In addition to an uneventful, baseline segment of driving, participants were challenged with collision avoidance and distracted driving scenarios. Under the influence of marijuana, participants decreased their speed and failed to show expected practice effects during a distracted drive. No differences were found during the baseline driving segment or collision avoidance scenarios. No differences attributable to sex were observed. This study enhances the current literature by identifying distracted driving and the integration of prior experience as particularly problematic under the influence of marijuana.

Sex, drugs, and cognition: effects of marijuana.

Despite the knowledge that many drugs affect men and women differently, few studies exploring the effects of marijuana use on cognition have included women. Findings from both animal and human studies suggest marijuana may have more marked effects in women. This study examined sex differences in the acute effects of marijuana on cognition in 70 (n=35 male, 35 female) occasional users of marijuana. Tasks were chosen to tap a wide variety of cognitive domains affected by sex and/or marijuana including attention, cognitive flexibility, time estimation, and visuospatial processing. As expected, acute marijuana use impaired performance on selective and divided attention, time estimation, and cognitive flexibility. While there did not appear to be sex differences in marijuana's effects on cognition, women requested to discontinue the smoking session more often than men, likely leading to an underestimation of differences. Further study of psychological differences in marijuana's effects on men and women following both acute and residual effects of marijuana is warranted.

Awareness during anesthesia: risk factors, causes and sequelae: a review of reported cases in the literature.

BACKGROUND: Awareness during anesthesia is uncommon. The number of cases that are found in one single study are insufficient to identify and estimate the risks, causal factors and sequelae. One method of studying a large number of cases is to analyze reports of cases of awareness that have been published in scientific journals. METHODS: We conducted an electronic search of the literature in the National Library of Medicine's PubMed database for case reports on "Awareness" and "Anesthesia" for the time period between 1950 through August, 2005. We also manually searched references cited in these reports and in other articles on awareness. We used two surgical control groups for comparative purposes. The first group in a study by Sebel et al. consisted of patients who did not experience awareness. The second group, from the 1996 data from the National Survey of Ambulatory Surgery included patients who received general anesthesia. We also used data from the National Center for Health Statistics to compare weight and Body Mass Index. RESULTS: We compared the data of 271 cases of awareness with 19,504 patients who did not suffer it. Aware patients were more likely to be females (P < 0.05), younger (P < 0.001) and to have cardiac and obstetrics operations (P < 0.0001). Only 35% reported the awareness episode during the stay in the recovery room. They received fewer anesthetic drugs (P < 0.0001), and were more likely to exhibit episodes of tachycardia and hypertension during surgery (P < 0.0001). A much larger percentage of these patients (52%, P < 0.0001) voiced postoperative complaints related to awareness. Inability to move and feelings such as helplessness, sensation of weakness, and hearing noises and voices were related to the persistence of complaints such as sleep disturbances and fear about future anesthetics (P < 0.041-0.0003). Twenty-two percent of the patients suffered late psychological symptoms. CONCLUSIONS: Our review suggested light anesthesia and a history of awareness as risk factors. Obesity and avoidance of nitrous oxide use did not seem to increase the risk. Light anesthesia was the most common cause. Our findings suggest preventive procedures that may lead to a decrease in the incidence of awareness.

Iowa Case Management for Rural Drug Abuse.

OBJECTIVE: The purpose of this research was to evaluate the effectiveness of a comprehensive, strengths-based model of case management for clients in drug abuse treatment. METHOD: 503 volunteers from residential or intensive outpatient treatment were randomly assigned to one of three conditions of Iowa Case Management (ICM) plus treatment as usual (TAU), or to a fourth condition of TAU only. All were assessed at intake and followed at 3, 6, and 12 months. RESULTS: Clients in all four conditions significantly decreased substance use by 3 months after intake and maintained most gains over time. However, the addition of ICM to TAU did not improve substance use outcomes. CONCLUSION: Overall, the addition of case management did not significantly improve drug treatment as hypothesized by both researchers and clinicians. Some results were mixed, possibly due to the heterogeneous sample, wide range of case management activities, or difficulty retaining participants over time.

Effects of smoking marijuana on focal attention and brain blood flow.

Using an attention task to control cognitive state, we previously found that smoking marijuana changes regional cerebral blood flow (rCBF). The present study measured rCBF during tasks requiring attention to left and right ears in different conditions. Twelve occasional marijuana users (mean age 23.5 years) were imaged with PET using [15O]water after smoking marijuana or placebo cigarettes as they performed a reaction time (RT) baseline task, and a dichotic listening task with attend-right- and attend-left-ear instructions. Smoking marijuana, but not placebo, resulted in increased normalized rCBF in orbital frontal cortex, anterior cingulate, temporal pole, insula, and cerebellum. RCBF was reduced in visual and auditory cortices. These changes occurred in all three tasks and replicated our earlier studies. They appear to reflect the direct effects of marijuana on the brain. Smoking marijuana lowered rCBF in auditory cortices compared to placebo but did not alter the normal pattern of attention-related rCBF asymmetry (i.e., greater rCBF in the temporal lobe contralateral to the direction of attention) that was also observed after placebo. These data indicate that marijuana has dramatic direct effects on rCBF, but causes relatively little change in the normal pattern of task-related rCBF on this auditory focused attention task.