ADHD or attention deficit hyperactivity disorder has gained immense importance both among the clinicians and researchers because of its early onset, variable clinical presentations, and prominent heritability. Along with the established symptom clusters of attention deficit and hyperactivity, a load of comorbidities have been found hugely prevalent for this population, increasing the morbidity and distress level and turning the management more complex. The early childhood and adolescent onset of this externalizing behavior-based disorder also makes the individual more prone to other externalizing behavioral problems, like addiction to variable psychoactive substances. Adolescent, being a natural age towards risk taking and novelty seeking, addiction proneness itself is a major individual and public health challenge to which ADHD works as potential fuel. In recent times, the upsurge of various behavioral addictions has also been seen prominently in the ADHD population increasing the morbidity and complexity. Treatment options need to be researched in detail.
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Comorbidity is almost a rule in case of ADHD in both children and adults as it impacts their ability to function successfully. However the conditions could be both comorbid disorders and differential diagnoses (with behaviours similar to that of ADHD), to be recognised in their individual capacity. Multiple comorbidities have been correlated with ADHD, some of them are Bipolar affective disorder, Obsessive compulsive disorder (OCD), Sensory Integration Disorder, Early Speech/Communication problems, substance abuse disorder, conduct disorder (CD), Major depressive disorder, Communication disorder, Social phobia and Separation anxiety disorder, etc.
Substance Use Disorder (SUD) and ADHD seem to have bidirectional relationship. Study of their comorbidity is pertinent to research and clinical practice in developmental pediatrics, psychology and psychiatry. The study is useful for diagnosis, prognosis, treatment and healthcare delivery. Based on available facts, about a quarter to half of adolescents and adults with SUD have ADHD.
ADHD is a chronic condition which is often correlated with demoralization and failure. An improvement in attention and executive functions has been identified by adults with addiction to nicotine, similar to a literature recommendation in the treatment of ADHD. There has also been reports of emotional ease and help with falling asleep by adolescents with active SUD, stated as a reason of their substance use. Based on this, “self-medication” hypothesis has gained limelight.
Prevalence of Substance Abuse in ADHD
A number of studies with clinical as well as population samples show that the probability of receiving a diagnosis of SUD is high in adolescents and adults with ADHD. Thus, it may be summed up that each of these comorbidities as an individual diagnosis already has its numerous negative effects and it becomes the most problematic conditions when it is seen together with ADHD. Many studies and reviews have documented that individuals with ADHD are at risk for increased substance use, abuse, and experimentation (Barkley, Fischer, Smallish, & Fletcher, 2004; Burke, Loeber, & Lahey, 2001; Charach, Yeung, Climans, & Lillie, 2011; Faraone et al., 2007; Gittelman, Mannuzza, Shenker, & Bonagura, 1985; Hartsough & Lambert, 1987; Lee, Humphreys, Flory, Liu, & Glass, 2011; Molina & Pelham, 2014; Molina, Flory et al., 2007; Molina & Pelham, 2003; Molina, Smith, & Pelham, 1999; Sibley, Pelham, Molina, Kipp, Gnagy, Meinzer, Ross & Lahey, 2014a; Wilson & Levin, 2005).
In a meta-analysis and meta-regression study by Dennis (2004) including 29 international studies it was reported that 23.1% of young adults diagnosed with ADHD were also seeking treatment for SUD. The cross-sectional International ADHD in Substance Use Disorders Prevalence (IASP) study on a sample of 3,558, among 10 countries, a prevalence of 40.0% for ADHD in patients seeking treatment for SUD was reported. In a screening study carried out in Istanbul with 4,938 10th-grade students from 45 schools in 15 districts by Evren, Dalbudak, Evren, Can, Umut (2014), the severity of ADHD symptoms were found to be higher in students with a lifetime history of smoking and alcohol/substance use.