Investigating the effects of age, IQ, dosing, and anthropometric measures on the treatment persistence in long-term methylphenidate use

Abstract

Objectives

This study aimed to determine anthropometric and clinical correlates of persistence to methylphenidate (MPH) treatment in Turkish youth with attention-deficit hyperactivity disorder (ADHD).

Methods

Data from medical records of 518 children and adolescents with ADHD were recorded between March 2012 and January 2022. Clinical variables of patients persistent to MPH ≥ 2 years were compared with those of the non-persistent group. Children and adolescent age groups were compared using Kaplan–Meier estimates for treatment drop-outs. Cox regression analysis until the treatment drop-out was implemented to calculate hazard ratios (HRs) for gender, age, full-scale IQ, and anthropometric measures. Weight, height, and body mass index (BMI) z-scores were calculated per national guidelines.

Results

Persistent and non-persistent study groups had similar full-scale IQ, weight, height, and BMI z-scores at treatment onset. The mean MPH dose was significantly higher in the persistent group compared to the non-persistent counterparts (31.43 ± 10.70 vs. 24.28 ± 9.60 mg/d, p < 0.001, d = 0.70). Compared to children, the adolescents showed earlier treatment drop-outs in males (p < 0.001) but not in females (p = 0.110). Younger age showed a positive effect on treatment persistence. Conversely, baseline BMI and IQ scores were not associated with long-term persistence.

Discussion

Our study demonstrated lower daily doses and older age-onset were associated with early drop-outs in MPH treatment. These findings supported the notion that effective dosing strategies at younger ages could increase the sustainability of the treatment with MPH in the Turkish population.

Keywords:

• ADHD
• methylphenidate
• adherence
• persistence
• children

Acknowledgments

All authors made substantial contributions to conception and design, and/or acquisition of data, interpretation of data, and writing article.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Notes on contributors

Dr. Mustafa Tuncturk became a child and adolescent psychiatry consultant in 2019. He is still working in Bakirkoy Mental Health Hospital. He is conducting research on ADHD, mood disorders, psychosis and psychotropic medications.

Dr. Cagatay Ermis has graduated from Ege University Medical School in 2015 and completed his residency at Dokuz Eylul University in 2020. He is still working in Diyarbakir as a child psychiatry consultant. His primary research focuses are cognition, mood disorders, psychosis and psychotropic medications.

Dr. Dicle Buyuktaskin has graduated from Marmara University Medical School in 2014 and completed her residency at Gazi University in 2019. She is a PhD candidate on Neuroscience and working as a child psychiatry consultant in Turkey. Her primary research focuses are neurodevelopmental disorders and art psychotherapy.

Dr. Eren Halac has graduated from Akdeniz University Medical School in 2015 and started his residency at Dokuz Eylul University in 2018. He continues her specialty education in the department of child and adolescent psychiatry. His primary research focuses are ADHD, Learning Disorders, sluggish cognitive tempo, mood disorders, psychosis and psychotropic medications.

Dr. Ekin Sut has graduated from Hacettepe University Medical School in 2015 and started his residency at Dokuz Eylul University in 2019. She continues her specialty education in the department of child and adolescent psychiatry. Her primary research focuses are early intervention, mood disorders, psychosis and psychotropic medications.

Dr. Oben Ozkan has graduated from Ege University Medical School in 2020 and started his residency at Dokuz Eylul University in 2021. She continues her specialty education in the department of child and adolescent psychiatry. Her primary research focuses are neurodevelopmental disorders, psychosis and psychotropic medications.

Dr. Nazan Gundogan has graduated from Uludag University Medical School in 2018 and started her residency at Dokuz Eylul University im 2018. She continues her specialty education in the department of child and adolescent psychiatry. Her primary research focuses are neurodevelopmental disorders, psychosis, anxiety disorders and cyberbullying.

Dr. Guldal Unutmaz has graduated from Manisa Celal Bayar University Medical School in 2021 and started her residency at Dokuz Eylul University in 2021. She continues her specialty education in the department of child and adolescent psychiatry. Her primary researh focuses are ADHD, mood disorders, psychosis and psychotropic medications.

Dr. Ogulcan Ciray has graduated from residency at Dokuz Eylul University in 2020. He is still working Mardin State Hospital as a child psychiatry consultant. He is interested in efficacy and safety of psychotropic medications and systematic literature reviews.

Dr. Serkan Turan has graduated from residency at Dokuz Eylul University in 2018. He is still working Bursa Uludag Universirt Hospital as a child psychiatry consultant. He is interested in efficacy anf safety of psychotropic medications and ADHD.

Aynur Akay Pekcanlar, Prof. Dr. has completed here residency at Dokuz Eylul University. She is still working in İzmir as a child psychiatry consultant. Her primary research focuses are cognition, ADHD and psychotropic medications.