Published in BJPsych Open(Cambridge) on 22/01/2024

Suicide and the association of mental illness, particularly attention-deficit hyperactivity disorder (ADHD), with increased risk of suicide attempts and mortality is a significant public health concern in the USA.

Traditional theories have focused on depression and isolation as primary risk factors for suicide, but there is a growing body of research suggesting that ADHD, characterized by impulsivity and emotional regulation challenges, may also play a role. The incidence of ADHD has increased among adults in the past two decades, with stimulants being the primary medication used to treat ADHD.

A study found that individuals had a lower risk of suicide attempts during months when they were receiving a stimulant medication. However, there has been no study examining the effects of ADHD medication on the risk of suicide mortality.

Therefore, the objective of the study discussed is to determine if active stimulant medication treatment among individuals diagnosed with ADHD is associated with a decreased risk of suicide mortality.

How was the study designed?

The study analyzed the use of stimulant medications for patients with an active ADHD diagnosis in the Department of Veterans Affairs. The researchers assessed whether patients with ADHD had active stimulant prescriptions, including dextroamphetamine, amphetaminedextroamphetamine, dexmethylphenidate, methylphenidate, and lisdexamfetamine. Active stimulant prescriptions were identified as any filled prescription with overlapping days’ supply within a given month. The study included patients who had at least one active stimulant prescription between 2016 and 2019. The researchers examined the average number of months patients were on versus off stimulants and also considered demographic characteristics, such as gender, race/ethnicity, and age at the time of their index use. The findings of the study provide insights into the patterns of stimulant medication use among patients with ADHD and the demographic factors associated with their usage.

How were the results calculated?

The study compared the risk of suicide, overdose, and external-cause mortality in patients on stimulant prescriptions versus off stimulant prescriptions at a population level. The researchers used discrete time-series logistic regression to observe the risk for each month a patient used the prescription, from their index date until their ADHD diagnosis became inactive, they died, or the study period ended. The analysis compared the risk of mortality during medicated and unmedicated months, adjusting for patient demographic characteristics, time-varying covariates such as the number of patient appointments and non-stimulant psychiatric prescriptions, and a time-varying covariate summarizing patients’ mental health burden in the 12 months before the month of interest. The models used clustered robust standard errors to account for correlations between months at the patient level.

What were the findings of this study?

• The study involved 73,177 Department of Veterans Affairs patients with an active ADHD diagnosis, predominantly men and White, with a mean age of 39.4.
• Patients were followed for an average of 29.8 months and had an average active stimulant prescription fill of 18.5 person-months.
• A high percentage of patients had comorbid diagnoses of depression (45.5%) and trauma-related disorders (44.3%) with ADHD.
• Patients on stimulant medication experienced increased outpatient visits for both mental health and non-mental health care, while inpatient stays decreased.
• Additionally, receipt of non-stimulant medication, including antidepressants, antipsychotics, mood stabilizers, opioids, opioid agonists, and sedative anxiolytics, increased during months on stimulant medication.
• The odds ratio of suicide mortality during months on stimulant medication was 0.57 (95% CI 0.36-0.88) compared with months off of stimulant medication.
• The odds ratios for overdoses and external-cause mortality during months on versus off stimulant medication were 0.77 (95% CI 0.58-1.02) and 0.66 (95% CI 0.53-0.83), respectively.

These findings indicate a potential association between stimulant medication use and a decreased risk of suicide mortality, as well as reduced risk of overdoses and external-cause mortality.

What are the Implications of these results? What do authors recommend?

The findings revealed that active stimulant medication use was linked to a decreased risk of suicide mortality, overdose, and external-cause mortality. The authors suggested that these results were not due to misclassification of patient deaths.

They emphasized that evidence-based treatments for mental illness, such as stimulant medications, may play a role in reducing the risk of suicide mortality.

The study also highlighted the potential impact of ADHD-specific symptoms like impulsivity on suicide risk. Additionally, it pointed out the need for further research to replicate the findings in different populations and to explore the effects of stimulant medication on impulsivity and suicide risk. In conclusion, the study concluded that treatment with stimulant medications for patients diagnosed with ADHD is associated with a reduced risk of suicide mortality, calling for further replication of the methods and exploration of ADHD-specific symptoms in relation to suicide risk.

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References:

Rice, K. M., Peltzman, T., Gottlieb, D., Shiner, B., & Watts, B. V. (2024). Stimulant medication and suicide mortality in attention-deficit hyperactivity disorder. BJPsych Open, 10(1), e33. doi:10.1192/bjo.2023.643