Kenneth M. Greenwood

Cognitive effects of long-term benzodiazepine use: A meta-analysis

AbstractIntroduction: While benzodiazepines are the most widely used psychotropic drugs, there are relatively few studies that have examined deficits in cognitive functioning after long-term use. The literature that is available is difficult to interpret due to conflicting results as well as a variety of methodological flaws. Objective: To systematically evaluate and integrate the available research findings to determine the effect of long-term benzodiazepine use on cognitive functioning using meta-analytical techniques. Methods: Thirteen research studies that employed neuropsychological tests to evaluate cognitive performance after long-term use of benzodiazepine medication met inclusion criteria. The neuropsychological tests employed in these 13 studies were each categorised as measuring one of 12 cognitive domains. Separate effect sizes were calculated for each of the 12 cognitive categories. Each study was only allowed to contribute one effect size to each cognitive category by averaging together the effect sizes from the same study if more than one type of test was used to measure a particular category. This strategy resulted in equal weight being given to each study per category, regardless of the number of tests in that category. Results: The overall mean number of patients who were benzodiazepine users was 33.5 (SD ± 28.9) and the mean number of controls was 27.9 (SD ± 19.6). The duration of benzodiazepine use ranged from 1 to 34 (mean 9.9) years. Long-term benzodiazepine users were consistently more impaired than controls across all cognitive categories examined, with effect sizes ranging in magnitude from −1.30 to −0.42. The mean weighted effect size was −0.74 (SD ± 0.25). None of the effect sizes had 95% CIs that spanned zero and, therefore, all of these effects were significant and different to zero. Conclusion: Moderate-to-large weighted effect sizes were found for all cognitive domains suggesting that long-term benzodiazepine users were significantly impaired, compared with controls, in all of the areas that were assessed. However, this study has several limitations, one being that it includes a relatively small number of studies. Further studies need to be conducted; ideally, well designed, controlled studies that thoroughly investigate certain areas of cognitive functioning and present data in such a way so as to be amenable to inclusion in a meta-analysis. Incorporating the information from these studies into a larger meta-analysis would allow for a more thorough and statistically sound investigation of the effects of moderator variables. The observation that long-term benzodiazepine use leads to a generalised effect on cognition has numerous implications for the informed and responsible prescription of these drugs.

Prevalence of voice problems in teachers

Teachers are frequently cited as experiencing a high rate of vocal dysfunction (1-7). Despite considerable research in the area of voice problems in teachers, the prevalence of voice disorders in this group is unknown. This study investigated the prevalence of self-reported voice problems in teachers using a mail survey of a simple random sample of 1168 state school teachers (preschool-Grade 12) in South Australia. As part of the survey, teachers were asked to report voice problems for the day of the survey, during the current teaching year, and during their careers. The response rate was 75%, with 16% of teachers reporting voice problems on the day of the survey, 20% reporting problems during the current teaching year, and 19% reporting problems at some time during their career. Females were twice as likely as males to report voice problems. These findings clearly indicate a need for further investigation of the causes of vocal dysfunction in teachers and for the development of educational programs aimed at preventing voice problems in this group of professional voice users.

Persistence of cognitive effects after withdrawal from long-term benzodiazepine use: A meta-analysis

Despite the widespread prescribing of benzodiazepines, uncertainty still surrounds the potential for cognitive impairment following their long-term use. Furthermore, the degree of recovery that may take place after withdrawal or the level of residual impairment, if any, that is maintained in long-term benzodiazepine users is also unclear. The current paper employed meta-analytic techniques to address two questions: (1) Does the cognitive function of long-term benzodiazepine users improve following withdrawal? (2) Are previous long-term benzodiazepine users still impaired at follow-up compared to controls or normative data? Results of the meta-analyses indicated that long-term benzodiazepine users do show recovery of function in many areas after withdrawal. However, there remains a significant impairment in most areas of cognition in comparison to controls or normative data. The findings of this study highlight the problems associated with long-term benzodiazepine therapy and suggest that previous benzodiazepine users would be likely to experience the benefit of improved cognitive functioning after withdrawal. However, the reviewed data did not support full restitution of function, at least in the first 6 months following cessation and suggest that there may be some permanent deficits or deficits that take longer than 6 months to completely recover.

Intelligence and Duchenne muscular dystrophy: Full-Scale, Verbal, and Performance intelligence quotients

Duchenne muscular dystrophy (DMD) is a disease which has as its hallmarks progressive muscle weakness and degeneration of skeletal muscle. Also observed among those with DMD is a higher rate of mental retardation* than in the normally developing population. While estimates for the prevalence of mental retardation in the normally developing population are approximately 9%,1 estimates of mental retardation based on the administration of the Wechsler Intelligence Scales (WIS)2,3 or the Stanford-Binet4 to children with DMD have ranged from 20%5 to as high as 50% in some studies.6–8 There have been intermittent review articles9 focusing on this issue, with authors noting aspects of the prevalence discrepancy, but no large-scale collation of the considerable published DMD intelligence data has yet been undertaken. The purpose of this paper is to provide an up-to-date review of this literature, and to report, as well as to summarize, the preliminary results of a metaanalysis of the available data, focusing on on global intelligence measures and DMD.

Association between intellectual functioning and age in children and young adults with Duchenne muscular dystrophy: Further results from a meta-analysis

This study used meta‐analytical techniques to explore the association between intelligence and age in children with Duchenne muscular dystrophy (DMD). The sample comprised 1224 children and young adults with DMD (mean age 12y 3mo, SD 4y; range 2y to 27y). Standardized measures including the Wechsler Intelligence Scales (WIS) and the Stanford‐Binet Intelligence Scales were used to estimate intelligence. No age‐related difference was noted for Full‐scale and Performance intelligence quotients (IQ). However, Verbal IQ increased significantly with age. Age‐related increases were noted for the WIS Information, Similarities, Arithmetic, Comprehension, Digit Span, Picture Arrangement, Block Design, and Coding subscales. These results support the notion that younger children with DMD have deficits in verbal reasoning and verbal processing. Older children with DMD, particularly those of 14 years and older, were less likely to present with these problems. Implications of these findings and possible future research directions are discussed.

Do Transtheoretical Model Measures Predict the Transition from Preparation to Action in Smoking Cessation

This study tested the predictive value of the Transtheoretical Model (TTM) for the preparation to action stage transition by conducting a detailed examination of changes in TTM components in the days leading up to, and following, a planned quit attempt. Participants were 193 callers to a Quitline telephone service. Only limited support for the TTM was found. Consistent with the TTM, measures of self-efficacy were related to making an attempt and to achieving 7 + days of abstinence. Contrary to the TTM, the behavioral change processes were unrelated to making quit attempts and to short-term abstinence, with the exception of self-liberation, which is conceptually related to self-efficacy. New non-TTM measures assessing commitment to quitting were predictive of outcomes. The results provide strong support for the preparation to action transition being discontinuous, and thus consistent with a stage model. However, they bring into question many of the other postulates of the TTM. Further critical testing and evaluation of the TTM is required.

Rehabilitation team decisions on discharge housing for stroke patients

For older people who have had a stroke, appropriate housing can promote independence and well being. However, suboptimal team accommodation recommendations may result in placement of an individual where their needs are not met, and their skills are not maximized. Although clinical judgments regarding patient discharge are routinely made by rehabilitation teams, this area has received limited research attention. This study examines how rehabilitation teams determine the most appropriate housing to recommend to stroke patients after their discharge from hospitals. A Social Judgment Theory approach was used to document and analyze the accommodation recommendations and policies of 13 rehabilitation teams (clinician n = 74). Teams were asked to consider 50 hypothetical stroke patients, and determine the most appropriate discharge housing to recommend to these patients. Each stroke patient was described in terms of 8 attributes: mobility status, ability to manage their own affairs, patients choice of housing, personal activity of daily living (ADL) skills, domestic and community ADL skills, general health status, social situation, and premorbid living arrangements. Clinicians were provided with a response scale on which to record their recommendations. The results showed considerable yet reliable differences among teams concerning recommendations made, and judgment policies adopted. Although the highly structured and hypothetical nature of this research limits the external validity of findings, the results suggest that teams may also face difficulties with housing recommendations in the more complex clinical environment. Further studies to assess actual clinical team decision making are needed. Such studies could lead to the development of a standardized research-based protocol to help teams formalize and optimize their housing recommendations.

Accident Cognitions and Subsequent Psychological Trauma

This study used a sample of 72 consecutive attendees to hospital following motor vehicle accidents. It aimed to assess the relationship between demographic variables, details of the accident and cognitions about the accident recorded soon afterward, and degree of psychological trauma 3 and 6 months later. Psychological trauma was assessed using the General Health Questionnaire, Impact of Event Scale, and Posttraumatic Stress Disorder Interview. A structured interview was used to gain information about demographic, accident, and accident cognition variables. Results showed that initial cognitions such as perceived threat to life, rather than demographic or accident variables, had the strongest relationships to subsequent trauma.

An evaluation of persisting cognitive effects after withdrawal from long-term benzodiazepine use

Twenty participants with self-reported long-term benzodiazepine use (mean 108 months) who had previously withdrawn from medication (mean 42 months) were administered a battery of neuropsychological tests. Each long-term user was case matched for age, sex, and education to two control participants who reported never taking benzodiazepines (those with and those without anxiety). The results indicated that long-term benzodiazepine use may lead to impairments in the areas of verbal memory, motor control/performance, and nonverbal memory but not visuospatial skills and attention/concentration. The length of abstinence (> 6 months) indicates that these impairments persist well beyond cessation of benzodiazepine use. However, observed impairments in the area of nonverbal memory were not solely attributable to benzodiazepine use and may be influenced by the elevated anxiety levels present in both the case and the anxious control group.

Coping style and psychological trauma after road accidents

This prospective study aimed to follow a cohort of road accident victims for 6 months and to examine changes in psychological trauma and coping styles over this time. It also aimed to examine the relationship between initial coping style and subsequent psychological trauma. Seventy-two consecutive hospital attendees were assessed using the General Health Questionnaire, Impact of Event Scale, Posttraumatic Stress Disorder Interview and the Coping Inventory for Stressful Situations. Results showed that there was little change in reported coping style over the 6 months but there was a significant decrease in scores on trauma symptom measures. Initial emotion-focussed coping style and to a lesser extent avoidance had strong positive relationships with later trauma scores.