Benzodiazepine dependence in Singapore

The study, conducted in 2003–2005, was aimed at investigating the pattern of benzodiazepine (BZD) use and the attitudes and perceptions of doctors' prescribing practices by a hundred BZD-dependent patients in Singapore. Data on patients' demographic characteristics, psychiatric profiles, patterns of BZD use, and perceptions about doctors' prescribing practices were collected. A benzodiazepine dependence self-report questionnaire (Bendep-SRQ) was also administered. The mean age of the study participants was 39.4 years (SD = 9.7); 88% were Chinese, 58% were males, 46% were married, 48% had received secondary school education, and 48% were unemployed. BZD abuse in Singapore is contributed to by both doctor-shopping behavior and doctors' prescribing practices. Doctors need training on the assessment and management of BZD dependence. The study's limitations were noted. This project was supported by an institutional block grant received from the National Medical Research Council, Singapore.

Keywords: BZD dependence; doctor-shopping; psychiatric comorbidity

Benzodiazepines (BZDs) are minor tranquilizers used to relieve stress, anxiety, and insomnia and have been prescribed as anticonvulsants, muscle relaxants, and anesthetic agents prior to surgery. Adverse effects of benzodiazepines include cognitive impairment, lack of motivation, drowsiness, and central nervous system depression (Woods, Katz, and Winger, [12]). Benzodiazepine dependence is a common complication of high-dose or long-term BZD use (Marriott and Tyrer, [7]; Miller and Gold, [9]) and is characterized by a well-defined withdrawal syndrome (Ashton, [1]). The proportion of BZD users for nonmedical purposes is rising worldwide. A study analyzing data from a nationally representative sample of U.S. college students in 2001 reported the lifetime prevalence of nonmedical prescription benzodiazepine use to be 7.8% (McCabe, [8]). Australians using tranquilizers and sleeping pills for nonmedical purposes doubled from 3% in 1995 to 6% in 1998 (Australian Institute of Health and Welfare, [2]).

Our study was aimed at examining the demographic, substance use profile, and psychiatric comorbidity of patients presenting with BZD dependence to the Community Addictions Management Program (CAMP) in Singapore.

This study was conducted with patients attending the outpatient clinics of the CAMP diagnosed with BZD dependence according to DSM-IV criteria. Ethical approval for the study was given by the hospital's research and ethics committee. Patients were approached by the researcher, a trained substance abuse counselor, and informed about the study. Patients who expressed interest and consented to taking part in the study were recruited. All 100 consecutive patients who met the inclusion and exclusion criteria consented to taking part in the study; none of the patients dropped out of the study.

The mean age of the study participants was 39.4 years (SD = 9.7); 88% were Chinese, 58% were males, 46% were married, 48% had received secondary school education, and 48% were unemployed. Forty-one percent of patients had a family member who suffered from addiction; 60% had used illicit drugs in the past and had recently switched to prescription drug (benzodiazepine) use. Twenty-four percent had a lifetime history of depression (Table 1).

Table 1 Selected sociodemographic and clinical characteristics of benzodiazepines misusers

Baseline urine tests for amphetamine, opiates, THC, and breath alcohol level were performed by the hospital's laboratory to ensure that patients were not intoxicated. Trained case managers administered the Benzodiazepine Dependence Self-Report Questionnaire (short version; Bendep-SRQ) and conducted a semi-structured clinical interview. The Bendep-SRQ is a 20-item questionnaire pertaining to patient's dependence on the medication and side effects experienced when patient tries to cut down on the same. Five-point items were rated by the respondent according to the degree to which they apply to him or her. The severity of BZD dependence is assessed across four scales: problematic use, preoccupation, lack of compliance, and withdrawal. Together, the scores on these scales constitute a multidimensional severity profile of BZD dependence (Kan, Breteler, Timmermans, van der Ven, and Zitman, [5]; Kan, Breteler, van der Ven, and Zitman, [6]). The questionnaire for the semistructured clinical interview was developed based on a survey of GPs BZD prescribing patterns and dilemmas experienced by physicians when prescribing BZDs (Bendtsen, Hensing, McKenzie, and Stridsman, [3]; Boixet, Batlle, and Bolibar, [4]). Some questions about a doctor's prescribing pattern and patients' perceptions and attitudes have been taken and modified from a patient survey questionnaire about substance abuse[1] developed by the National Center on Addiction and Substance Abuse (2000).

All analyses were performed with SPSS statistical software version 13.0 with statistical significance set at p < 0.05. Descriptive statistics using frequency distributions and the percentage (with 95% confidence interval) of patients were taken. The association between the severity of BZD dependence with doctor-shopping behavior and doctors' prescribing practice was assessed using chi-square or Fisher's exact tests.

Our patients presented with severe BZD dependence with large amounts of daily consumption and a long duration of use. Midazolam (Dormicum°) was the drug of choice for BZD abuse and dependence (69%). A number of BZD-dependent patients (17%) used the intravenous route for BZD (mostly midazolam) administration (Table 2).

Table 2 Pattern of benzodiazepine use

2020 *Dose equivalences: diazepam 5 mg, midazolam 1.25 mg, nimetazepam 2.5 mg, alprazolam 0.5 mg, lorazepam 1 mg, clonazepam 0.25 mg.

Curiosity (54%) and insomnia (37%) were the two most significant reasons for initiating BZD use. With the regular daily use of BZD, almost one third of patients (32%) became aware of their dependence within 4 weeks. Most of the patients' BZD dependences were within the highly severe range for the four domains of Bendep-SRQ (Table 3).

Table 3 Severity of BZD dependence measured by Bendep-SRQ

2021 *Problematic use: Degree of awareness of problematic use. Preoccupation: Degree of preoccupation/obsession with respect to the availability of BZDs. Lack of compliance: Degree of lack of compliance with the therapeutic BZD. Withdrawal: Degree of unambiguity of experienced BZD withdrawal.

Patients obtained their BZDs primarily from local GPs (75%) and secondarily from the black market (33%). Doctor-shopping behavior was evident with frequent monthly clinic visits (6 visits per month). The total number of different doctors ever visited was 12 (± 11). The most frequently used reason for obtaining BZDs was insomnia (72%). Most GPs (66%) did not ask about the patient's substance abuse history prior to their BZD prescription. Only half of the GPs assessed the regular BZD users for dependence on an ongoing basis. Most of the patients (62%) initiated the discussion of problematic BZD use with their GPs. Almost half of the patients (47%) sought GPs as their first line of treatment for their problematic BZD use.

The pattern of BZD use in Singapore is characterized by the fact that most patients reported initiating their BZD use out of curiosity rather than for insomnia. This can be considered to be evidence of the fact that in Singapore there is a growing trend among ex-illicit drug users to switch to prescription drug (BZD) abuse. Their choice BZD of abuse is the short-acting midazolam and there is a significant diversion of BZD tablets for misuse. A small but significant number of patients were observed to use the intravenous route to administer BZDs using crushed midazolam tablets. These patients pose a significant public health risk as they expose themselves to medical complications such as endocarditis and septicemia or bloodborne diseases like hepatitis or HIV.

Doctor-shopping behavior is prevalent among our BZD-dependent patients. Most patients obtain their BZDs from GPs, and insomnia was the most frequently used complaint during their GP visits. Many patients reported an easy accessibility to BZDs from GPs, and this could be related to the individual operations at each private practice. This must be understood in the context of Singapore's health care system, where, like most Asian countries, doctors perform a dual role as prescribers and dispensers. The diversion is in large part due to individual doctor's inability to get an accurate history of the patient's BZD use or dependence. They have to rely largely on accounts from the patient, which may be fictitious. The lack of any centralized registry or shared medical records is significant in perpetuating patients' BZD dependence. The common advice provided by doctors was to cut down or quit BZD use, but without adequate exploration of their prior use patterns and dependence, there was understandably little education or referral for counseling or coping skills sessions for lifestyle change. This is consistent with a report by Parr, Kavanagh, Young, and McCafferty ([11]), where BZD users indicated insufficient advice on nonpharmacological management for their problems before commencing BZDs.

This study has some limitations: firstly, the findings cannot be generalized to the general population, as the sample size is relatively small and subjects were the more chronic BZD users with severe dependence referred for tertiary care. Second, the clinical interview was conducted among BZD-dependent patients, and views from the primary doctors were not examined. As such, further studies involving GPs' needs in managing BZD-dependent patients are recommended.

This study shows that there is a definite need for systemic planning and implementation in both the training and education of GPs in using benzodiazepine medications and in possibly developing a central register to prevent doctor-shopping. The authors also feel that clinical practice guidelines should be implemented for benzodiazepines to ensure that nonpharmacological options like lifestyle counselling and sleep hygiene are considered before the prescribing of benzodiazepines.

L'étude entreprise en 2003–2005, a été visée étudiant le modèle de l'utilisation de la benzodiazépine (BZD) et des attitudes et la perception de la pratique en matière de prescription des médecins par cent patients BZD-dépendants à Singapour. Des données sur des caractéristiques démographiques de patients, le profil psychiatrique, modèle de l'utilisation de BZD, perception sur la pratique en matière de prescription des médecins ont été rassemblées. Le questionnaire de la dépendance art de l'auto-portrait-report de benzodiazépine (Bendep-SRQ) a été également administré. L'âge moyen des participants d'étude était de 39.4 ans (S.D. = 9.7); 88% étaient chinois, 58% étaient des mâles, 46% étaient mariés, 48% avait reçu l'éducation d'école secondaire, et 48% étaient sans emploi. L'abus de BZD à Singapour est contribué par tous les deux comportement d'docteur-achats et pratiques en matière de prescription des médecins. Les médecins ont besoin s'exercer sur l'évaluation et la gestion de la dépendance de BZD. Les limitations de l'étude ont été notées. Ce projet a été soutenu par un bloc institutionnel Grant reçu du Conseil "Recherche" médical national, Singapour.

El estudio conducido en 2003–2005, fue dirigido investigando el patrón del uso del benzodiazepine (BZD) y de las actitudes y la opinión de la práctica que prescribía de los doctores por cientos pacientes BZD-dependientes en Singapur. Los datos sobre características demográficas de los pacientes, perfil psiquiátrico, patrón del uso de BZD, opinión en la práctica que prescribía de los doctores fueron recogidos. El cuestionario del uno mismo-informe de la dependencia de Benzodiazepine (Bendep-SRQ) también fue administrado. La edad media de los participantes del estudio era 39.4 años (S.D. = 9.7); los 88% eran chinos, los 58% eran varones, los 46% fueron casados, el 48% habían recibido la educación de la escuela secundaria, y los 48% estaban parados. El abuso de BZD en Singapur es contribuido por ambos comportamiento de las doctor-compras y las prácticas que prescriben de los doctores. Los doctores necesitan entrenar en el gravamen y la gerencia de la dependencia de BZD. Las limitaciones del estudio fueron observadas. Este proyecto fue apoyado por un bloque institucional Grant recibido del consejo de investigación médica nacional, Singapur.

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Catherine Dong (Yanhong Dong), B.N., Grad Dip (psychology), MHSci (beh sci), MappSci (beh sci), CSAC, CGAC, is working as a substance abuse counselor in the Addiction Medicine Department, Institute of Mental Health. Her areas of interest are prescription drug abuse and dependence and clinical program evaluation.

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Munidasa Winslow, MBBS, Mmed (psychiatry), is the head of the Department of Addiction Medicine and a senior consultant in the Institute of Mental Health, Singapore. His areas of interest include substance and behavioral addictions as well as program evaluations.

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Chan Yiong Huak, Ph.D., is working as the head of the Biostatistics Unit, Yong Loo Lin School of Medicine, National University of Singapore. His areas of interest are biostatistics, clinical trials, and epidemiological study designs.

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Mythily Subramaniam, M.D, M.H.S.M, is working as a research manager in the Department of Addiction Medicine, Institute of Mental Health, Singapore. Her areas of interest include early psychosis and addiction.

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Gregory Whelan, MBBS, M.D., M.Sc., FRACP, FAFPHM, FAChAM, is a professor of addiction medicine at the University of Melbourne and Monash University in Victoria Australia. He is also the medical director of the Victorian Addiction Centre.

We thank the Research Division of Institute of Mental Health for its support and Janice Chua and Dr. Guo Song for their input. The authors also thank the NUH-NUS Medical Publications Support Unit for their assistance in the preparation of this manuscript.