How Common is Use of Pharmacogenetic Drugs Among Young People With and Without Mental Disorders?

What you need to know

• By age 35, up to 97% of people with mental disorders and 65% of females/23% of males without mental disorders had used at least one medication that could benefit from pharmacogenetic testing.

• The most common pharmacogenetic drugs used were related to mental health conditions, pain relief, stomach acid, and birth control.

• People started using these medications at a young age - as early as 11 years old on average for males with ADHD or autism.

• Many people used multiple pharmacogenetic drugs over time, suggesting potential benefit from comprehensive genetic testing panels rather than single-gene tests.

What is pharmacogenetics?

Pharmacogenetics is the study of how a person’s genes affect their response to medications. Certain genetic variations can impact how quickly or slowly someone metabolizes (breaks down) different drugs. This can affect:

• How well a medication works for that person
• The proper dose they need
• Their risk of side effects

Pharmacogenetic testing looks at specific genes to help predict how someone may respond to certain medications before they even take them. This allows doctors to potentially choose more effective drugs and doses for each individual patient.

What did this study examine?

This study looked at how often young people in Denmark used medications that have pharmacogenetic recommendations - meaning genetic testing could potentially help guide their use. The researchers analyzed prescription records for over 86,000 people born between 1981-2005, including:

• 56,065 people diagnosed with mental health conditions like ADHD, autism, depression, bipolar disorder, or schizophrenia
• 29,975 people from the general population without these diagnoses

They tracked medication use from 1995 through 2016, for up to 22 years of data per person.

How common was use of pharmacogenetic medications?

By age 35, a large proportion of people had used at least one medication with pharmacogenetic recommendations:

• 97% of females and 87% of males with schizophrenia
• 97% of females and 87% of males with bipolar disorder
• 97% of females and 87% of males with depression
• 85% of females and 56% of males with ADHD
• 72% of females and 44% of males with autism
• 65% of females and 23% of males without mental health diagnoses

So use was very common, especially among those with mental health conditions. Females generally used these medications more often than males.

What were the most commonly used pharmacogenetic drugs?

The most frequently used medications varied between groups:

General population:

• Birth control pills (females)
• Pain relievers like codeine and tramadol
• Stomach acid reducers like omeprazole
• Antidepressants like citalopram

People with mental health conditions:

• Medications matching their diagnosis, like:
  • Atomoxetine for ADHD
  • Aripiprazole for schizophrenia
  • Lamotrigine for bipolar disorder
  • Citalopram for depression
• Pain relievers
• Stomach acid reducers
• Birth control pills (females)

How young did people start using these medications?

Many people started using pharmacogenetic medications at a young age:

• As early as 11 years old on average for males with ADHD or autism
• 13 years old on average for females with ADHD or autism
• 13 years old for males and 15 years old for females without mental health diagnoses

This suggests genetic testing could potentially be helpful even in adolescence for some individuals.

Why does this matter?

Knowing how common use of these medications is, and how early it starts, can help inform decisions about if and when to consider pharmacogenetic testing.

Currently, genetic testing related to medications is often done reactively - after someone has already had issues with a drug not working well or causing side effects. But this data suggests many people could potentially benefit from proactive testing before ever starting certain medications.

The high rates of use also indicate that panel-based testing - looking at multiple genes at once - may be more useful than only testing single genes. Many people used several different pharmacogenetic drugs over time that are affected by different genes.

What are the potential benefits of pharmacogenetic testing?

Pharmacogenetic testing aims to help doctors:

• Choose medications more likely to work well for each patient
• Avoid drugs more likely to cause side effects
• Select appropriate dosages based on how quickly someone metabolizes a drug

This could potentially lead to more effective treatment with fewer adverse effects. It may be especially beneficial for people with mental health conditions, who often have to try multiple medications before finding one that works well.

What are some limitations to consider?

This study only looked at how often these medications were prescribed and picked up from pharmacies. It didn’t examine whether genetic testing actually improved outcomes for patients. More research is still needed on the real-world benefits of pharmacogenetic testing.

The study also focused on young people in Denmark, so the results may not apply equally to other age groups or countries with different prescribing patterns.

Additionally, genetic testing recommendations continue to evolve as we learn more. This study was based on current guidelines, but those may change over time as research advances.

Conclusions

• Use of medications that could benefit from pharmacogenetic testing is very common, especially among young people with mental health conditions.

• Many people start using these drugs at a young age, suggesting potential value in early genetic testing for some individuals.

• The frequent use of multiple pharmacogenetic drugs over time indicates comprehensive gene panels may be more useful than single-gene tests.

• More research is still needed on whether routine pharmacogenetic testing actually improves patient outcomes in real-world practice.