Investigating the Relationship Between Attention-Deficit Hyperactivity Disorder, Obligatory Exercise and Exercise Addiction

Abstract

Attention-deficit hyperactivity disorder (ADHD) affects around 5% of children and adults worldwide (Polanczyk et al., 2015; Simon et al., 2009) and is characterised by inattention, impulsivity and hyperactivity (American Psychiatric Association, 2000). Having ADHD incurs greater risk of learning, behavioural and emotional problems, poorer educational outcomes, lower occupational status and relationship problems (Faraone et al., 2000). Psychostimulants (e.g. amphetamine and methylphenidate) are the most effective treatments available for all ages and the first line treatment for adults. They reduce symptoms in around 80% of patients (Barkley et al., 1991; Dittmann et al., 2014; Milich et al., 2001). However, whilst they can be effective, many experience residual symptoms (Dittmann et al., 2014) or significant side effects (Mariani et al., 2007), and there are concerns that the drugs may be abused (Darredeau et al., 2007; Laviola et al., 1999; Schenk & Davidson, 1998). Non-stimulant treatments exist, but the response rate is lower (Dittmann et al., 2014), and many still experience side effects (Mariani et al., 2007). Given the limitations of the available medications, other therapeutic approaches are being considered. Exercise has been shown to improve symptoms and cognitive functioning in children with ADHD (Chang et al., 2012; Jensen & Kenny, 2004; Piepmeier et al., 2015) and may also be beneficial for adults (Abramovitch et al., 2013). Exercise within the context of ADHD has been the focus of several systematic reviews and meta-analyses in recent years, all of which have found exercise to offer some functional improvement (Cerrillo-Urbina et al., 2015; Neudecker et al., 2019; Suarez-Manzano et al., 2018; Vysniauske et al., 2016). The exact mechanism by which exercise might alleviate ADHD symptoms is unknown, but both exercise and psychostimulants act on dopamine and BDNF suggesting there may be shared mechanisms (Archer & Kostrzewa, 2012; Ji et al., 2014; Kim et al., 2011; Kuczenski & Segal, 1997, 2002; Powers, 2000). As indicated above, one of the concerns about psychostimulant medication is its risk of abuse. Indeed ADHD is often