Samantha Hollingworth

Affective and anxiety disorders: prevalence, treatment and antidepressant medication use

Objective: The aim of the present study was to investigate the prevalence and treatment of affective and anxiety disorders in adults in Australia and compare these with the dispensed prescriptions of drugs used to treat these disorders. Methods: Analysis was done of the 2007 National Survey of Mental Health and Wellbeing regarding 12 month prevalence and treatment for affective and anxiety disorders and Pharmaceutical Benefits Scheme prescribing data for antidepressants for 2002–2007. The main outcome measures were prevalence and treatment (rates per 1000 population) and antidepressant utilization (defined daily dose 1000 population−1 day–1) by gender and age (5 and 10 year age groups). Results: The prevalence and treatment of affective and anxiety disorder are highest in those aged <50, after which it declines rapidly. Rates for both are higher in women than men. Overall antidepressant use increased 41% over the study period (selective serotonin re-uptake inhibitors 44%, venlafaxine 75%). Sertraline held the majority of the market, followed by venlafaxine and citalopram. Utilization of antidepressants had a bimodal distribution with peaks in those aged in their late 50s and early 90s. The peak use of antidepressants was in those aged 90–94 years. Conclusion: There is poor alignment between the prevalence and self-reported treatment of affective and anxiety disorders in the community and the prescribing of medications for these disorders. It appears that older Australians are receiving antidepressant medications for reasons other than the treatment of conditions for which these drugs have marketing approval or for depressive and anxiety symptoms that do not reach the threshold for a diagnosis.

Patterns of antipsychotic medication use in Australia 2002–2007

Objective: Atypical antipsychotic medications that are primarily used to treat schizophrenia and bipolar disorder cost the Pharmaceutical Benefits Scheme (PBS) AUD

Anxiolytic, hypnotic and sedative medication use in Australia

334.4m in 2007. There are indications that they have also been used outside the approved indications to treat behavioural disturbances in the elderly. The aim of the present study was therefore to examine (i) trends in prescribing of subsidized atypical antipsychotic drugs in the Australian population from 2002 to 2007; and (ii) gender and age differences in the utilization of these drugs. Methods: Government (Medicare Australia) data on numbers of prescriptions, quantity and doses for atypical and typical antipsychotics from 2002 to 2007 were analysed. Defined daily dose per 1000 population per day were estimated for age and sex groups using Australian Bureau of Statistics population data. Results: The proportion of prescribed antipsychotics that were atypical increased from 61% in 2002 to 77% in 2007. In male subjects, olanzapine was most often prescribed between the ages of 25 and 55 years. In female subjects, in contrast, the highest rates of prescribing were in those ≥75 years. Lower doses of these drugs were prescribed in older adults. Conclusions: Atypical antipsychotic drugs were most commonly used to treat schizophrenia in younger men and behavioural disturbances in older women with dementia. They appear to have been used outside of the approved indication for schizophrenia and bipolar disorder with significant financial costs to the PBS. Research into the reasons for their extensive use in elderly women is needed to inform more rational prescribing of these medicines.

Marked increase in proton pump inhibitors use in Australia

New sedative drugs have been marketed in Australia in the last few years. We examined the trends in the prescribing of subsidised anxiolytic, hypnotic and sedative (AHS) medication use in the Australian population from 2002 to 2007.

Changing patterns of antiepileptic drug use in pregnant Australian women

To examine the trends in the prescribing of subsidised proton pump inhibitors (PPIs) and histamine receptor antagonists (H2RAs), in the Australian population from 1995 to 2006 to encourage discussion regarding appropriate clinical use. PPIs and H2RAs are the second highest drug cost to the publicly subsidised Pharmaceutical Benefits Scheme (PBS).

Antiepileptic drugs in Australia: 2002–2007†

Vajda FJE, Hollingworth S, Graham J, Hitchcock AA, O’Brien TJ, Lander CM, Eadie MJ. Changing patterns of antiepileptic drug use in pregnant Australian women.
Acta Neurol Scand: 2010: 121: 89–93.
© 2009 The Authors Journal compilation

Effect of late hypothalamo-pituitary disconnection on the development of the HPA axis in the ovine fetus and the initiation of parturition.

With the marketing of a number of new antiepileptic drugs (AEDs) in recent years it seemed possible that the pattern of Australian prescribing for patients with epilepsy may have been changing. We examined the trends in the prescribing of subsidised AEDs in the Australian population from 2002 to 2007.

Australian national trends in stimulant dispensing: 2002-2009.

The studies of Liggins et al. (1) in which fetuses stalk‐sectioned from day 116 onwards delivered at or near term, suggested that a connection between the fetal hypothalamus and pituitary is not essential for parturition to occur. The objective of this study was to repeat these experiments on the effects of pituitary stalk sections at different gestational ages and include information on the plasma concentrations of key fetal hormones. We have used the more sophisticated technique of hypothalamo‐pituitary disconnection (HPD) at either of two gestational age ranges (123–127 days or 133–135 days). Completeness of the procedure was assessed by demonstrating an attenuated prolactin response to chlorpromazine challenge. Following HPD, gestation was prolonged for at least eight days beyond term (146.2 ± 1.5 days) in 9 of the 10 fetuses operated. Fetal plasma ACTH1–39 concentrations were not different between the HPD and control fetuses, increasing in all groups with increasing gestation. Fetal plasma cortisol concentrations increased (P<0.01) in control fetuses over gestation. Cortisol concentrations did not change significantly in the day 125 HPD group following HPD but increased in the day 135 HPD group (P<0.05) with advancing gestation. These latter concentrations, however were markedly less (P< 0.001) than those for control fetuses prior to parturition. Fetal and maternal plasma PGE2 concentrations increased (P<0.01) in the control group over gestation but did not change following HPD. Maternal plasma progesterone concentrations decreased (P<0.05) after day 143 in the control group but did not change in the HPD group. There was no change in maternal plasma concentrations of prostaglandin FM in the HPD group. These findings demonstrate that hypothalamic connection to the pituitary needs to be maintained until at least day 135 of gestation for the initiation of parturition at term.

Opioid analgesic prescribing in Australia: a focus on gender and age

Objective: Internationally there has been an increase in the prescriptions of stimulant medication. The aim of this study was to examine longitudinal national trends of stimulant dispensing in Australia between 2002 and 2009. Method: Government databases were retrospectively reviewed for all dispensed stimulant prescriptions between 2002 and 2009. Prescriptions were converted to defined daily dose (DDD)/1000 population/day using census data. Utilization of dexamphetamine and methylphenidate were analysed by source (subsidized or non-subsidized), prescriber (general practitioner, psychiatrist or other specialists), gender and age of patient. Results: Between 2002 and 2009, dispensing of stimulants in Australia increased 87% from 2.93 to 5.47 DDD/1000 population/day. Dexamphetamine remained the most commonly dispensed stimulant, with rates of dispensing falling 13% from 2.02 to 1.75 DDD/1000 population/day. Dispensed prescriptions of methylphenidate increased 300% from 0.45 in 2002 to 1.81 DDD/1000 population/day in 2009, attributable to the availability of long-acting preparations. Dispensing of stimulants to males was four-fold greater than to females. There was substantial dispensing of dexamphetamine to those older than 25 years. Conclusions: Stimulant dispensing in Australia increased between 2002 and 2009 as a result of increased dispensing of long-acting preparations of methylphenidate. Further research is required to determine if the increase in stimulant dispensing in Australia is clinically appropriate.

International trends in clozapine use: a study in 17 countries

The use of prescription opioid analgesics has been increasing over the last few decades in Australia. In particular, oxycodone and fentanyl have increased substantially. We examined the gender and age trends in the prescribing of subsidised opioid analgesics in the Australian population for non‐palliative care indications.