Martin Frisher

Effect of anxiolytic and hypnotic drug prescriptions on mortality hazards: retrospective cohort study.

Objective To test the hypothesis that people taking anxiolytic and hypnotic drugs are at increased risk of premature mortality, using primary care prescription records and after adjusting for a wide range of potential confounders. Design Retrospective cohort study. Setting 273 UK primary care practices contributing data to the General Practice Research Database. Participants 34 727 patients aged 16 years and older first prescribed anxiolytic or hypnotic drugs, or both, between 1998 and 2001, and 69 418 patients with no prescriptions for such drugs (controls) matched by age, sex, and practice. Patients were followed-up for a mean of 7.6 years (range 0.1-13.4 years). Main outcome All cause mortality ascertained from practice records. Results Physical and psychiatric comorbidities and prescribing of non-study drugs were significantly more prevalent among those prescribed study drugs than among controls. The age adjusted hazard ratio for mortality during the whole follow-up period for use of any study drug in the first year after recruitment was 3.46 (95% confidence interval 3.34 to 3.59) and 3.32 (3.19 to 3.45) after adjusting for other potential confounders. Dose-response associations were found for all three classes of study drugs (benzodiazepines, Z drugs (zaleplon, zolpidem, and zopiclone), and other drugs). After excluding deaths in the first year, there were approximately four excess deaths linked to drug use per 100 people followed for an average of 7.6 years after their first prescription. Conclusions In this large cohort of patients attending UK primary care, anxiolytic and hypnotic drugs were associated with significantly increased risk of mortality over a seven year period, after adjusting for a range of potential confounders. As with all observational findings, however, these results are prone to bias arising from unmeasured and residual confounding.

Assessing the impact of cannabis use on trends in diagnosed schizophrenia in the United Kingdom from 1996 to 2005

A recent systematic review concluded that cannabis use increases risk of psychotic outcomes independently of confounding and transient intoxication effects. Furthermore, a model of the association between cannabis use and schizophrenia indicated that the incidence and prevalence of schizophrenia would increase from 1990 onwards. The model is based on three factors: a) increased relative risk of psychotic outcomes for frequent cannabis users compared to those who have never used cannabis between 1.8 and 3.1, b) a substantial rise in UK cannabis use from the mid-1970s and c) elevated risk of 20 years from first use of cannabis. This paper investigates whether this has occurred in the UK by examining trends in the annual prevalence and incidence of schizophrenia and psychoses, as measured by diagnosed cases from 1996 to 2005. Retrospective analysis of the General Practice Research Database (GPRD) was conducted for 183 practices in England, Wales, Scotland and Northern Ireland. The study cohort comprised almost 600,000 patients each year, representing approximately 2.3% of the UK population aged 16 to 44. Between 1996 and 2005 the incidence and prevalence of schizophrenia and psychoses were either stable or declining. Explanations other than a genuine stability or decline were considered, but appeared less plausible. In conclusion, this study did not find any evidence of increasing schizophrenia or psychoses in the general population from 1996 to 2005.

Prevalence of comorbid psychiatric illness and substance misuse in primary care in England and Wales

Study objective: To estimate the annual period prevalence of co-occurring psychiatric illness and substance misuse among patients in primary care. Design: Analysis of the general practice research database. Setting: England and Wales, 1993–1998. Participants: Registered patients at 230 general practices representing 3.1% of the population. A comorbid case was defined as one with both a psychiatric diagnosis and substance misuse diagnosis (not including alcohol or tobacco) within a calendar year. A potentially chronic comorbid case was one that met this definition and, in addition, was treated in subsequent years for either a psychiatric condition or substance misuse. Main results: The annual period prevalence of comorbidity increased from 50/100 000 patient years of exposure (PYE) to 80/100 000 PYE, an increase of 62% during the study period. Rates of comorbid psychoses, comorbid schizophrenia, and comorbid paranoia increased by 147%, 128%, and 144%. The average age of comorbid cases decreased from 38 years to 34 years. Over 80% of comorbid cases were newly diagnosed in each study year, although many are treated in subsequent years for either psychiatric illness or substance misuse. Conclusions: This study provides data on the nature and extent of comorbidity in primary care in England and Wales. As the comorbidity rate is increasing by about 10% each year, and as comorbid cases are becoming younger, it is probable that the comorbidity rate will have increased beyond the study end point.

Substance misuse and psychiatric illness: prospective observational study using the general practice research database

Objectives: To quantify the relation between substance misuse and psychiatric illness in the UK general practice population in terms of (a) the relative risk of developing one condition given prior exposure to the other and (b) the proportion of cases of one condition attributable to exposure to the other. Design: Population based prospective observational study using the general practice research database (GPRD) between 1993 and 1998. The 230 GP practices represent 3.1% of the population. Setting: England and Wales. Participants: 1.4 million registered patients of whom 3969 had both substance misuse and psychiatric diagnoses between 1993 and 1998. Main outcome measures: Relative risk (RR) for subsequent psychiatric illness among participants exposed to substance misuse and RR for subsequent substance misuse among participants exposed to psychiatric illness. Population attributable risk (PAR) of psychiatric illness attributable to substance misuse and of substance misuse attributable to psychiatric illness. Results: The baseline prevalence of psychiatric illness over the study period was 15% and 0.3% for substance abuse. RR for psychiatric illness for substance misusers compared with non-substance misusers was 1.54 (95% CI 1.47 to 1.62). RR for substance misuse among psychiatric compared with non-psychiatric cases was 2.09 (95% CI 1.99 to 2.22). PAR for psychiatric illness attributable to substance misuse was 0.2%. PAR for substance misuse attributable to psychiatric illness was 14.2%. Discussion: Only a comparatively small proportion of psychiatric illness seems possibly attributable to substance use whereas a more substantial proportion of substance use seems possibly attributable to psychiatric illness. This study does not support the hypotheses that comorbidity between substance misuse and psychiatric illness is primarily the result of substance misuse or that increasing comorbidity is largely attributable to increasing substance misuse.

Is alcohol consumption in older adults associated with poor self-rated health? Cross-sectional and longitudinal analyses from the English Longitudinal Study of Ageing

BackgroundIncreases in alcohol related mortality and morbidity have been reported among older people in England over the last decade. There is, however, evidence that drinking is protective for some health conditions. The validity of this evidence has been questioned due to residual confounding and selection bias. The aim of this study is to clarify which drinking profiles and other demographic characteristics are associated with poor self-rated health among a community-based sample of older adults in England. The study also examines whether drinking designated as being “increasing-risk” or “higher-risk” is associated with poorer self-rated health.MethodThis study used data from Wave 0, Wave 1 and Wave 5 of the English Longitudinal Study of Ageing [ELSA]. Logistic regression analysis, was used to examine the association between drinking profiles (based on quantity and frequency of drinking) and self-rated health, adjusting for gender, age, wealth, social class, education, household composition, smoking and body mass index [BMI].ResultsTwenty percent of the sample reported drinking above the recommended level at wave 0. Rates of poor self-rated health were highest among those who had stopped drinking, followed by those who never drank. The rates of poor self-rated health among non-drinkers were significantly higher than the rates of poor self-rated health for any of the groups who reported alcohol consumption. In the adjusted logistic regression models there were no drinking profiles associated with significantly higher rates of poor self-rated health relative to occasional drinkers.ConclusionsAmong those who drank alcohol, there was no evidence that any pattern of current alcohol consumption was associated with poor self-rated health, even after adjustment for a wide range of variables. The results associated with the stopped drinking profile indicate improvement in self-rated health can be associated with changes in drinking behaviour. Although several limitations of the study are noted, policy makers may wish to consider how these findings should be translated into drinking guidelines for older adults.

A comparison of psychotropic medication prescribing patterns in East of England prisons and the general population

While the prevalence of mental illness is higher in prisons than in the community, less is known about comparative rates of psychotropic medicine prescribing. This is the first study in a decade to determine the prevalence and patterns of psychotropic medication prescribing in prisons. It is also the first study to comprehensively adjust for age when making comparisons with the general population. Four East of England prisons, housing a total of 2222 men and 341 women were recruited to the study. On census days, clinical records were used to identify and collect data on all prisoners with current, valid prescriptions for hypnotic, anxiolytic, antipsychotic, antimanic, antidepressant and/or stimulant medication, as listed in chapters 4.1 to 4.4 of the British National Formulary. Data on 280,168 patients were obtained for comparison purposes from the Clinical Practice Research Datalink. After adjusting for age, rates of psychotropic prescribing in prison were 5.5 and 5.9 times higher than in community-based men and women, respectively. We also found marked differences in the individual psychotropic drugs prescribed in prison and community settings. Further work is necessary to determine whether psychotropic prescribing patterns in prison reflect an appropriate balance between managing mental illness, physical health risks and medication misuse.

Drug use desistance

Drug dependence is generally thought to involve a loss or reduction of individual autonomy. Yet of the 11 million people in the UK (27 per cent of the population aged 16–74) who have ever used illicit drugs at some point in their life, probably no more than 300,000 (1%) are drug dependent. Many commentators find the apparently self-destructive behaviour of problematic drug users difficult to explain. According to rational theory, choices are made with respect to a long timeframe so as to maximize overall utility. Under maximization, individuals cannot gradually slide towards a very high level of drug use at the expense of other activities as this would reduce their overall utility. The key to understanding drug dependence is that it involves ‘matching’ different behavioural combinations at any given point in time that do not take account of long-term consequences. There is growing evidence that drug users are much more likely to match compared to non-drug users and that they have difficulty in learning to maximize. We argue that current practice within the UK criminal justice system is implicitly based on the idea that relearning the value of alternative behaviours can lead to drug use desistance.

Is regular drinking in later life an indicator of good health? Evidence from the English Longitudinal Study of Ageing

Background Older people who drink have been shown to have better health than those who do not. This might suggest that moderate drinking is beneficial for health, or, as considered here, that older people modify their drinking as their health deteriorates. The relationship between how often older adults drink and their health is considered for two heath states: self-rated health (SRH) and depressive symptoms. Methods Data were analysed from the English Longitudinal Study of Ageing (ELSA), a prospective cohort study of older adults, using multilevel ordered logit analysis. The analysis involved 4741 participants present at wave 0, (1998/1999 and 2001), wave 4 (2008/2009) and wave 5 (2010/2011). The outcome measure was frequency of drinking in last year recorded at all three time points. Results Older adults with fair/poor SRH at the onset of the study drank less frequently compared with adults with good SRH (p<0.05). Drinking frequency declined over time for all health statuses, though respondents with both continual fair/poor SRH and declining SRH experienced a sharper reduction in the frequency of their drinking over time compared with older adults who remained in good SRH or whose health improved. The findings were similar for depression, though the association between depressive symptoms and drinking frequency at the baseline was not significant after adjusting for confounding variables. Conclusions The frequency of older adults’ drinking responds to changes in health status and drinking frequency in later life may be an indicator, rather than a cause, of health status.

Trends in drug misuse recorded in primary care in the UK from 1998 to 2005

BACKGROUND A recent report by the UK Drugs Policy Commission has highlighted the high levels of drug use in Britain and this has been interpreted as indicative of ineffective drug polices. However, the interpretation was based on sporadic self-report data and indirect extrapolation. This paper assesses trends in the prevalence and incidence of drug misuse in the UK from 1998 to 2005 as recorded in general practice. METHODS The study was a retrospective analysis of the General Practice Research Database. The study cohort comprised approximately 900,000 patients each year from 183 general practices. RESULTS Among the Governments key target age group (16-24 years), there was a marked decrease in both prevalence and incidence of illicit drug misuse from 1998 to 2002 (P < 0.01). In older adults (25-59 years), the pattern was more variable during the first part of this period, but incidence remained stable from 2002 to 2005. CONCLUSIONS These data indicate that the problematic drug use in the UK may be declining and that the policies may be more effective than has been previously thought. General Practice data are nonetheless only part of the picture in terms of understanding the prevalence of problematic drug use.

Validating estimates of problematic drug use in England

BackgroundUK Government expenditure on combatting drug abuse is based on estimates of illicit drug users, yet the validity of these estimates is unknown. This study aims to assess the face validity of problematic drug use (PDU) and injecting drug use (IDU) estimates for all English Drug Action Teams (DATs) in 2001. The estimates were derived from a statistical model using the Multiple Indicator Method (MIM).MethodsQuestionnaire study, in which the 149 English Drug Action Teams were asked to evaluate the MIM estimates for their DAT.ResultsThe response rate was 60% and there were no indications of selection bias. Of responding DATs, 64% thought the PDU estimates were about right or did not dispute them, while 27% had estimates that were too low and 9% were too high. The figures for the IDU estimates were 52% (about right), 44% (too low) and 3% (too high).ConclusionThis is the first UK study to determine the validity estimates of problematic and injecting drug misuse. The results of this paper highlight the need to consider criterion and face validity when evaluating estimates of the number of drug users.