PhD defence Ms A.Y.L. (Adrienne) Chan

International diversity in psychotropic medication use

a pharmacoepidemiological perspective

Adrienne Chan investigated various aspects of psychotropic medication use and associated risks. 

Chan: 'Chapter 2 examined multinational trends in ADHD medication consumption across 64 countries. The results revealed a yearly increase of +9.72% in consumption, with notable differences between geographical locations. High-income countries exhibited higher consumption rates compared to middle-income countries. Notably, ADHD prevalence estimates and medication consumption in middle-income countries were lower than the global prevalence, highlighting the need to address barriers to diagnosis and treatment.

Chapter 3 explored opioid prescribing prevalence across countries/regions. Among over 240 million individuals, the prevalence ranged from 2.7% in Japan to 19.7% in Iceland, with variations by sex, age, and geographic region. While opioid prescribing remained unbalanced, convergence across countries/regions was observed. Future research should assess treatment needs and potential harm in specific sub-populations.

In Chapter 4, gabapentinoid consumption was examined on a global scale. The study showed a consistent increase in consumption worldwide, with high-income countries accounting for the highest rates. Gabapentinoids, originally developed for seizures and neuropathic pain, are increasingly utilised off-label, emphasising the need to understand the implications of their growing demand.

Chapter 5 analysed the impact of prenatal antidepressant and antipsychotic use on the risk of seizure in children. The results indicated an increased risk associated with maternal gestational use, but not when compared to maternal past use or to children of mothers without psychiatric disorders. Children whose mothers had a psychiatric disorder showed a consistently higher risk of seizures. Sibling-matched analyses and comparisons with gestationally nonexposed children yielded no significant associations.

Chapter 6 investigated the relationship between maternal use of benzodiazepine and/or z-drug exposure during pregnancy and birth (preterm birth and small for gestational age) and neurodevelopmental outcomes (autism spectrum disorder and attention-deficit/hyperactivity disorder). The findings did not support a causal relationship between benzodiazepine and/or z-drug exposure and these outcomes. Clinicians and pregnant women should weigh the known risks against the untreated anxiety and sleep problems when considering medication use.

Overall, these studies contribute valuable insights into utilisation trends and patterns of psychotropic medication use, associated risks, and the need for careful evaluation of benefits and potential harms in various populations. The studies in this thesis aim to bridge the current research gaps and provide important insights to guide policy formulation to improve health for people who requires psychotropic medication globally.'

Promotores Prof.dr. K. Taxis and Prof. dr. I. Chi Kei Wong