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Childhood ADHD medicines not linked to higher substance use later – US study

Providing a smidgen of reassurance to parents and clinicians, researchers say children prescribed with stimulants for attention deficit hyperactivity disorder (ADHD) do not have more substance use or substance use disorder (SUD) as adolescents or young adults.

The research, led by the University of Pittsburgh School of Medicine, may particularly reduce anxiety in doctors who may be hesitant to prescribe ADHD stimulant medications for fear they may lay the groundwork for future substance use, and for parents of these children, who also often harbour similar fears.

“Stimulants are the first-line treatment recommended for most people with ADHD,” said Brooke Molina, professor of psychiatry, psychology and paediatrics at Pitt. “Because stimulant medications are classified by the Drug Enforcement Administration as schedule two substances with the potential for misuse, many people fear that harmful substance use could result.”

Although ADHD can be managed with medication and other therapeutic approaches, it is a chronic condition that should be monitored throughout a person’s life, reports MedicalXPress.

For the study, published in JAMA Psychiatry, Molina and colleagues assessed patients with ADHD over a 16-year period from childhood through to adolescence to early adulthood to see if there were any association between stimulant treatment and subsequent substance use.

The study is among the first to address the relationship between childhood use of prescription stimulants and later SUD by accounting for dozens of demographic, clinical and psychosocial factors that may predispose an individual to treatment and substance use.

“Our study not only accounted for age, but also used a statistical method that adjusted over time for the many characteristics that may distinguish treated from non-treated individuals,” said study co-author Traci Kennedy, PhD, assistant professor of psychiatry at Pitt.

“Considering these factors allowed us to more accurately test the relationship between stimulants and substance use.”

While other studies have sought to uncover and define a possible connection between prescription stimulant use for ADHD and SUD, the association between the two has remained controversial.

The results of some studies suggested a protective effect of prescription stimulant use on the risk of having SUD later in life, while others failed to find an association.

When factoring in age and other time-varying characteristics, such as household income, behaviour problems and parental support, Pitt researchers found no evidence that prescription stimulant treatment in childhood provided protection against developing a SUD for adolescents or young adults with ADHD.

However, neither did they find an association between stimulant use during childhood and increased substance misuse in the future

While some study participants self-reported an increase over time in heavy drinking, marijuana use, daily cigarette smoking and using other substances, an association with age was also found for stimulant treatment, with older participants being less likely to continue taking medication.

When these trends were paired with rigorous statistical analysis, results provided no evidence that prolonged stimulant use is associated with reduced or increased risk for SUD.

Pitt researchers plan to study individuals who were first diagnosed with ADHD and treated with stimulants in adulthood. The study aims to learn if there are differences in the characteristics and outcomes of these adults compared with people who were diagnosed and first treated with stimulants in childhood.

This research was conducted as part of a randomised clinical trial in cooperative agreement with the National Institute of Mental Health.

Study details

Association Between Stimulant Treatment and Substance Use Through Adolescence Into Early Adulthood

Brooke Molina,  Traci Kennedy,  Andrea Howard, et al.

Published in JAMA Psychiatry on 5 July 2023

Key Points

Question Is stimulant medication for attention-deficit/hyperactivity disorder (ADHD) associated with later substance use after considering age and other confounding factors not previously studied?

Findings In this cohort study of 547 children initially treated in a randomised clinical trial for ADHD and assessed repeatedly to adulthood, comprehensive analyses did not support an association between stimulant treatment and adolescent or adulthood substance use or substance use disorder.

Meaning This study found no evidence that stimulant treatment, predominantly prescribed in childhood and adolescence, protects against or increases risk of later frequent use of alcohol, cigarettes, marijuana, or other substance use by a mean age of 25 years.

Abstract

Importance
Possible associations between stimulant treatment of attention-deficit/hyperactivity disorder (ADHD) and subsequent substance use remain debated and clinically relevant.

Objective
To assess the association of stimulant treatment of ADHD with subsequent substance use using the Multimodal Treatment Study of ADHD (MTA), which provides a unique opportunity to test this association while addressing methodologic complexities (principally, multiple dynamic confounding variables).

Design, Setting, and Participants
MTA was a multisite study initiated at six sites in the US and one in Canada as a 14-month randomised clinical trial of medication and behaviour therapy for ADHD but transitioned to a longitudinal observational study. Participants were recruited between 1994 and 1996. Multi-informant assessments included comprehensively assessed demographic, clinical (including substance use), and treatment (including stimulant treatment) variables. Children aged 7 to 9 years with rigorously diagnosed DSM-IV combined-type ADHD were repeatedly assessed until a mean age of 25 years. Analysis took place between April 2018 and February 2023.

Exposure
Stimulant treatment of ADHD was measured prospectively from baseline for 16 years (10 assessments) initially using parent report followed by young adult report.

Main Outcomes and Measures
Frequency of heavy drinking, marijuana use, daily cigarette smoking, and other substance use were confidentially self-reported with a standardised substance use questionnaire.

Results
A total of 579 children (mean [SD] age at baseline, 8.5 [0.8] years; 465 [80%] male) were analysed. Generalised multilevel linear models showed no evidence that current (B [SE] range, −0.62 [0.55] to 0.34 [0.47]) or prior stimulant treatment (B [SE] range, −0.06 [0.26] to 0.70 [0.37]) or their interaction (B [SE] range, −0.49 [0.70] to 0.86 [0.68]) were associated with substance use after adjusting for developmental trends in substance use and age. Marginal structural models adjusting for dynamic confounding by demographic, clinical, and familial factors revealed no evidence that more years of stimulant treatment (B [SE] range, −0.003 [0.01] to 0.04 [0.02]) or continuous, uninterrupted stimulant treatment (B [SE] range, −0.25 [0.33] to −0.03 [0.10]) were associated with adulthood substance use. Findings were the same for substance use disorder as outcome.

Conclusions and Relevance
This study found no evidence that stimulant treatment was associated with increased or decreased risk for later frequent use of alcohol, marijuana, cigarette smoking, or other substances used for adolescents and young adults with childhood ADHD. These findings do not appear to result from other factors that might drive treatment over time and findings held even after considering opposing age-related trends in stimulant treatment and substance use.

 

JAMA Psychiatry article – Association Between Stimulant Treatment and Substance Use Through Adolescence Into Early Adulthood (Open access)

 

MedicalXPress article – Treating childhood ADHD with stimulant meds not associated with increased substance use later in life, study finds (Open access)

 

See more from MedicalBrief archives:

 

Half of adults with ADHD have had a substance use disorder — Canadian study

 

Prescription ‘smart drugs’ have opposite effect in healthy adults – Australian study

 

Abnormal brain connectivity found in ADHD children – US study

 

White children likely to be over-diagnosed, over-treated for ADHD – US study

 

 

 

 

 

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