Introduction
Attention-deficit hyperactivity disorder (ADHD) is a neuro-behavioural disorder characterised by early onset of persistent inattention–disorganisation and hyperactivity–impulsivity causing significant impairment in executive and psychosocial function, with commencement during childhood, and with symptoms persisting into adulthood in up to 50% of patients (Fitzgerald, Reference Fitzgerald1998, Reference Fitzgerald2005; American Psychiatric Association, 2000; Biederman, Reference Biederman2005; Arias etal. Reference Arias, Gelernter, Chan, Weiss, Brady, Farrer, Farrer and Kranzler2008; Lee etal. Reference Lee, Humphreys, Flory, Liu and Glass2011; Castells etal. Reference Castells, Ramos-Quiroga, Bosch, Nogueira and Casas2011a). Global estimates of lifetime prevalence of childhood ADHD in the general population range between 5% and 12%, with ∼1–6% of adults (with average rates of 3–4%) having adult ADHD in the general population (Meltzer etal. Reference Meltzer, Gatward, Goodman and Ford2000; Scahill & Schwab-Stone Reference Scahill and Schwab-Stone2000; Lynskey & Hall, Reference Lynskey and Hall2001; Sullivan & Rudnik-Levin, Reference Sullivan and Rudnik-Levin2001; Wender etal. Reference Wender, Wolf and Wasserstein2001; Faraone etal. Reference Faraone, Sergeant, Gillberg and Biederman2003; Wilens, Reference Wilens2004; Kalbag & Levin, Reference Kalbag and Levin2005; Kessler etal. Reference Kessler, Adler, Barkley, Biederman, Conners and Demler2005, Reference Kessler, Adler, Barkley, Biederman, Conners, Faraone, Greenhill, Howes, Secnik, Spencer, Ustun, Walters and Zaslavsky2006; Fayyad etal. Reference Fayyad, De Graaf, Kessler, Alonso, Angermeyer, Demyttenaere, De Girolamo, Haro, Karam, Lara, Lepine, Ormel, Posada-Villa, Zaslavsky and Jin2007; Polanczyk & Rohde, Reference Polanczyk and Rohde2007). In Ireland, prevalence rates of ADHD in young Irish adolescents are similar to other western cultures (1–5%) (Kirley & Fitzgerald, Reference Kirley and Fitzgerald2002; Lynch etal. Reference Lynch, Mills, Daly and Fitzpatrick2006). Some Irish research has estimated the prevalence of ADHD in adult outpatient psychiatric patients to be close to 24%, with 56% reported as female and average age of 42.5 years (Syed etal. Reference Syed, Masaud, Nkire, Iro and Garland2010). The diagnosis of childhood ADHD is viewed as reliable and valid, with the validity of adult ADHD being somewhat complicated (Kirley & Fitzgerald, Reference Kirley and Fitzgerald2002). Research is suggestive of continued and underestimated expression of the disorder tracking into adulthood (Biederman etal. Reference Biederman, Farone, Milberger, Curtis, Chen, Marrs, Oeullette, Moore and Spencer1996; Barkley etal. Reference Barkley, Fischer, Smallish and Fletcher2002). Many adults with ADHD remain undiagnosed (Fitzgerald, Reference Fitzgerald2001). Rates of persistence of ADHD symptoms into adulthood vary between 50% and 80% cases (Fitzgerald, Reference Fitzgerald1998, Reference Fitzgerald2005; Kirley & Fitzgerald, Reference Kirley and Fitzgerald2002). Syed etal. (Reference Syed, Masaud, Nkire, Iro and Garland2010) in their Irish study reported significant underdiagnosis of ADHD, with no patients reporting a recorded diagnosis of adult ADHD.
ADHD is associated with a myriad of coexisting impairments such as mood instabilities (depression and anxiety), disruptive behaviours (oppositional defiant disorder, conduct disorders and Cluster-B personality disorders), neuro-psychological impairments (attention span, memory and concentration), family problems (family conflict and negative parental relations), academic problems (poor educational attainment and early school leaving), occupational underachievement (inability to attend school or university, although IQ is often higher than average) and social dysfunction (peer difficulties, impulsivity and anti-social behaviours) in both boys and girls, and identifiable from pre-school age (Kalbag & Levin, Reference Kalbag and Levin2005; Hinshaw etal. Reference Hinshaw, Owens, Sami and Fargeon2006; Lee etal. Reference Lee, Lahey, Owens and Hinshaw2008; Owens etal. Reference Owens, Hinshaw, Lee and Lahey2009; Biederman etal. Reference Biederman, Petty, Monuteaux, Fried, Byrne, Mirto, Spencer, Wilens and Faroane2010; Lee etal. Reference Lee, Humphreys, Flory, Liu and Glass2011; Castells etal. Reference Castells, Ramos-Quiroga, Bosch, Nogueira and Casas2011a).
Of interest for this research report is that ADHD symptoms can influence child and adolescent substance use by way of earlier ages of onset for difference substances, higher rates of use, displacements towards more serious forms of drug use, poly-substance use, increase addictive potential and pathways towards substance-use disorder (SUD) (Sullivan & Rudnik-Levin, Reference Sullivan and Rudnik-Levin2001; Davids & Gastpar, Reference Davids and Gastpar2003; Molina etal. Reference Molina, Marshal, Pelham and Wirth2005). Children of substance-abusing adults have a greater likelihood to develop ADHD, with problematic substance use frequently reported in households and from parents of children with ADHD (Chronis etal. Reference Chronis, Lahey, Pelham, Kipp, Baumann and Lee2003; Clarke & Fitzpatrick, Reference Clarke and Fitzpatrick2005). A co-occurring ADHD diagnosis is associated with heightened risk for substance experimentation, earlier onset of alcohol and drug use and a more serious trajectory of substance misuse and related problems (Biederman, 2000, Reference Biederman, Monuteaux, Mick, Spencer, Wilens, Silva, Snyder and Faroane2005); Charach etal. Reference Charach, Yeung, Climans and Lillie2011; Wilens etal. Reference Wilens, Martelon, Joshi, Bateman, Fried, Petty and Biederman2011; van Emmerik-van Oortmerssen etal. Reference van Emmerik-van Oortmerssen, van de Glind, van den Brink and Smit2012). ADHD and SUDs are proposed to share common genetic risk factors, similar personality, psychosocial and environmental factors, and may co-occur because of individual ‘self-medication’ of ADHD symtomatologies (Kalbag & Levin, Reference Kalbag and Levin2005) and equally as a result of difficulties incurred when early diagnosis and treatment do not occur, in terms of peer and school rejection, and association with anti-social peers engaging in substance misuse and/or criminal activity (Syed etal. Reference Syed, Masaud, Nkire, Iro and Garland2010). Quite commonly, adult ADHD cases with SUD describe an undiagnosed parent suffering with ADHD themselves and may experience substance misuse in the home.
In addition, when co-occurring with other common psychiatric disorders such as oppositional defiant disorder, conduct disorder and anti-social personality disorder, SUD trajectories and clinical outcomes are further complicated (Arias etal. Reference Arias, Gelernter, Chan, Weiss, Brady, Farrer, Farrer and Kranzler2008; Lee etal. Reference Lee, Humphreys, Flory, Liu and Glass2011). Adolescents with ADHD are more likely to smoke cigarettes, with cigarette smoking being associated with the development of adult SUD (Wilens & Upadhyaya, Reference Wilens and Upadhyaya2007). Prevalence of childhood and adult ADHD in those with SUDs are approximately one in five, but have been recorded as high as 83% (Sullivan & Rudnik-Levin, Reference Sullivan and Rudnik-Levin2001; Davids & Gastpar, Reference Davids and Gastpar2003; Kalbag & Levin, Reference Kalbag and Levin2005; Matsumoto etal. Reference Matsumoto, Kamijo, Yamaguchi, Iseki and Hirayasu2005; Wilens & Fusillo, Reference Wilens and Fusillo2007; Arias etal. Reference Arias, Gelernter, Chan, Weiss, Brady, Farrer, Farrer and Kranzler2008). SUD prevalence among the adult ADHD cohorts has been recorded as high as 35% (Kalbag & Levin, Reference Kalbag and Levin2005; Wilens & Upadhyaya, Reference Wilens and Upadhyaya2007). Irish data have recorded 11% of adult ADHD cases diagnosed with SUD (Syed etal. Reference Syed, Masaud, Nkire, Iro and Garland2010).
The treatment of childhood ADHD with stimulant medication (i.e. methylphenidate or atomoxetine) and the timing of such treatment, its mediation by the presence of other co-morbid conditions and its relationship with the development of future problematic substance use remains questionable (Lee etal. Reference Lee, Humphreys, Flory, Liu and Glass2011; Castells etal. Reference Castells, Ramos-Quiroga, Bosch, Nogueira and Casas2011a). Diversionary use of stimulant medication is of concern particularly among adolescents and young adults (Wilens & Fusillo, Reference Wilens and Fusillo2007). In terms of SUD treatment outcomes, the presence of ADHD is associated with higher relapse rates, with the stimulant treatment of ADHD not as effective in those with SUD (Carpentier etal. Reference Carpentier, de Jong, Dijkstra, Verbrugge and Krabbe2005; Levin etal. Reference Levin, Evans, Brooks and Garawi2006, Reference Levin, Evans, Brooks, Kalbag, Garawi and Nunes2007; Konstenius etal. Reference Konstenius, Jayaram-Lindström, Beck and Franck2010; Thurstone etal. Reference Thurstone, Riggs, Salomonsen-Sautel and Mikulich-Gilbertson2010; Castells etal. Reference Castells, Ramos-Quiroga, Rigau, Bosch, Nogueira, Vidal and Casas2011b). Research highlights the lack of clear effect of medication treatment on substance use (van Emmerik-van Oortmerssen etal. Reference van Emmerik-van Oortmerssen, van de Glind, van den Brink and Smit2012), with the exception of a study on cocaine-dependent ADHD patients receiving methylphenidate, whereby the reduction in ADHD symptoms was associated with reduced cocaine use, a typically impulsive form of drug-taking behaviour (Levin etal. Reference Levin, Evans, Brooks, Kalbag, Garawi and Nunes2006). Furthermore, ADHD symptoms such as inattention and impulsivity negatively affect treatment engagement, retention and outcomes and, because of symptom overlap, are not easily distinguishable from other psychiatric disorders or the symptoms of drug intoxication or withdrawal (Wilens & Upadhyaya, Reference Wilens and Upadhyaya2007; van Emmerik-van Oortmerssen etal. 2011; Matthies etal. Reference Matthies, Philipsen and Svaldi2012). Goossensen etal. (Reference Goossensen, van de Glind, Carpentier, Wijsen, van Duin and Kooij2006) have underscored the need to develop standardised protocols for the screening, diagnosis and treatment of ADHD in patients with SUD. In Ireland, as elsewhere, addiction treatment services may lack the expertises necessary for the screening, diagnosis and treatment of ADHD in SUD patients (Edokpolo etal. Reference Edokpolo, Nkire and Smyth2010).
This research report shall present preliminary findings relating to the occurrence of ADHD in new addiction treatment cases agreeing to partake in the study using the Adult ADHD Symptoms Rating Scale (ASRS-v1.1) (Van den Brink, Reference Van den Brink2012). The study was undertaken as part of the multi-site International ADHD in Substance Use Disorders Prevalence Study (IASP) directed by the International Collaboration on ADHD and Substance Abuse (ICASA) network. Eight European countries (Norway, Sweden, the Netherlands, Belgium, France, Spain, Switzerland and Hungary), United States and Australia participated in Phase II (closing in September 2011), with Ireland partaking in Phase II alongside South Africa, Egypt and Brazil.
MethodologyThe research was guided and sanctioned by the terms of reference of the Waterford Institute of Technology and Regional Health Service Executive (HSE) Research Ethics Committees, Ireland (January 2012). Addiction counsellors from participating outpatient and inpatient treatment settings in the South East region attended an in-depth IASP study protocol and assessment tool training course, provided by an experienced researcher from the ICASA network in November 2011. Following this training, adult ‘new treatment cases’ presenting to four treatment settings in the South East region (with the exception of those presenting with visible intoxication) were invited to participate. Those agreeing to participate were provided with an information leaflet detailing the study, confidentiality procedures and rights to withdraw. All participants were required to complete an informed consent form before participation.
Participants were asked to complete the self-report ASRS-v1.1 questionnaire, plus a demographic section including basic information about their problematic substance use. The ASRS is an 18-item self-report scale derived from the DSM-IV-TR diagnostic criteria for ADHD, comprising nine items on inattention and nine items on hyperactivity/impulsivity. It is widely used and has been validated in the Phase I IASP Studies for use ‘at the front door’ of treatment entry (Van den Brink, Reference Van den Brink2012), with a six-item ASRS screener shown to outperform the full version. For example, if four of these six items are endorsed, it indicates that the respondent has symptoms highly consistent with ADHD in adults and further investigation is warranted. Following a 2-week period of abstinence, participants were invited to complete the ASRS screener at a second time interval to screen for ADHD in the absence of obvious withdrawal symptoms and before the achievement of stable abstinence (Van den Brink, Reference Van den Brink2012). Data were analysed using PASW version 18 statistical software.
Results
A total of 49 treatment-seeking people agreed to take part in the study. Two participants did not partake in screening phase at the second time interval, leaving a total population of 47 participants having completed at time one and time two intervals. Thirty-four men and 13 women took part, with 33 Caucasian and the remainder undisclosed. The median age of the sample was 36 years. A majority were single (n = 34) with five married, four in a relationship, three separated and one widowed. Of the participants, 30 were unemployed, with eight in employment, two retired and one in receipt of disability allowance. A further six declined to indicate. Seventeen participants were engaged in treatment for Problematic Poly Substance use, followed by 14 in treatment for Problematic Alcohol use and 14 in treatment for Problematic Drug use. Table 1 shows the demographic details of the participants.
Table 1 Demographic participant details
A total of 10 participants screened positive at time one and this reduced to six participants at the time two interval. This indicates the occurrence of ADHD in these SUD patients was 13% (n = 6). Of the ADHD-positive cases at both time intervals, 100% (n = 6) were Caucasian and Male and had a median age of 23 years. Five were single, with one participant indicating that they were currently in a relationship. Five were unemployed. Four of the participants were being treated for Problem Poly Substance use, whereas two were being treated for Problem Drug use (opiates). None of the participants screening positive for ADHD were being treated for Problem Alcohol use.
Discussion
The IASP study Phase-I results indicate estimates of the prevalence of ADHD in treatment-seeking adults for SUD at between 20 and 25%. (Van den Brink, Reference Van den Brink2012). This preliminary Phase-II study indicates that 13% of adults seeking treatment for SUD were detected to screen positive for ADHD, with findings supporting the usefulness and cost-effectiveness of the ASRS to detect ADHD co-morbidity in SUD patients in addiction treatment settings. Similar to other existing Irish research (Syed etal. Reference Syed, Masaud, Nkire, Iro and Garland2010), none had received a confirmed diagnosis of childhood ADHD by a psychiatrist. There are only two dedicated Adult ADHD clinics in Ireland, with the public sector in Ireland not currently providing specialist clinics for the assessment and diagnosis of adult ADHD. The findings, although small scale and restricted by virtue of convenience sampling, are intended to fuel debate on the current situation in Ireland and useful to guide development of programmes to detect, diagnose and manage ADHD in those with SUD, contribute to improved and effective treatment of SUD in patients with co-morbid ADHD and inform strategies for the prevention and monitoring of SUD in children with ADHD in Ireland.
The participants screening positive for ADHD reported problem drug use. It is noteworthy that Irish psychiatric treatment statistics indicate an increase in the rate of drug-related first admissions, with a decrease in admissions to psychiatric facilities with an alcohol disorder (Daly and Walsh, Reference Daly and Walsh2010). However, this may have been because of the recent increase in the provision of community-based specialised addiction services in the reporting timeframe. Despite this, trends in first admissions for problematic alcohol use and prevalence of alcohol as primary problematic substances in addiction treatment services have increased in recent years (Carew etal. Reference Carew, Bellerose and Lyons2011). This indicates that dependence on alcohol (and indeed drugs) requires repeated treatment cycles. In addition, almost one in five alcohol-dependent treatment patients reported using at least one other substance, with common secondary substances of choice for use alongside alcohol, reportedly cannabis, cocaine, benzodiazepines and ecstasy, and indicating a shift away from opiates as a common additional drug (Carew etal. Reference Carew, Bellerose and Lyons2011). It should be noted that poly-substance use and associated problems increase the complexity of treatment and contribute to poorer outcomes (Carew etal. Reference Carew, Bellerose and Lyons2011). Trends in treated problem drug use also indicate a rise in prevalence, with opiates as the most common primary problem drug overall, and with first admissions reporting cannabis as a common main problem drug ahead of opiates in 2010 (Bellerose etal. Reference Bellerose, Carew and Lyons2011). This data series also reports on concerning increases in benzodiazepine misuse among first admissions, and a majority of cases reporting problem use of more than one substance (Bellerose etal. Reference Bellerose, Carew and Lyons2011). Similar to the sample profile in this study, drug treatment cases are predominantly male and in their 20s (Bellerose etal. Reference Bellerose, Carew and Lyons2011).
It should be noted that several pitfalls were identified in conducting this preliminary IASP study, which to date had not been undertaken in Ireland. Recruitment of treatment settings was problematic because of a lack of interest in ADHD, lack of time and staff work overload. In addition, several treatment settings that agreed to partake and attended the IASP training subsequently failed to commit to fieldwork. This was attributed to change of management and lack of professional support of the study objectives. In participating sites, several ASRS manuals were returned incomplete, leading to exclusion from the data entry. The sample is additionally compromised by convenience bias, with no information available on the level of patient refusal to participate and numbers of first admissions who were not invited to participate because of the participating addiction counsellors’ perception of chaotic behaviour or intoxication.
Conclusion
The prevalence of adult ADHD in SUD patients remains unknown in Ireland. However, the economic and public health burden of SUDs is no doubt compounded by the presence of ADHD patients in the form of treatment reuptake, frequent relapse and subsequent draw on existing addiction treatment resources. One cannot discount that the core symptoms of ADHD contribute to substance-related risk taking, and vice versa, the chosen substance(s) contribute to adverse affects of these symptoms. This contributes to serious forms of substance use, dependence and subsequent treatment failures (Sullivan & Rudnik-Levin, Reference Sullivan and Rudnik-Levin2001; Arias etal. Reference Arias, Gelernter, Chan, Weiss, Brady, Farrer, Farrer and Kranzler2008; Lee etal. Reference Lee, Humphreys, Flory, Liu and Glass2011; Matthies etal. Reference Matthies, Philipsen and Svaldi2012). Irish research has commented on difficulties in treating addiction patients with ADHD diagnosis who frequently have their medication stopped once SUD occurs, with subsequent addiction treatment taking preference over that of ADHD (Edokpolo etal. Reference Edokpolo, Nkire and Smyth2010). Clinician concerns over diversion and abuse of prescribed medication, potential worsening of SUD and drug interaction between illicit and prescribed are also evident in Ireland (Edokpolo etal. Reference Edokpolo, Nkire and Smyth2010).
Despite these concerns, the timely diagnosis and intervening treatment of adult ADHD has the potential to positively affect addiction treatment outcomes, with the design of specific treatment pathways for individuals with ADHD and SUD much needed in Ireland. The ASRS screener is a useful, cost- and time-effective tool to detect ADHD co-morbidity in SUD patients and can be easily utilised by Irish addiction teams on treatment entry. Most importantly, the consideration of combined pharmacological and psychosocial interventions (cognitive behavioural therapy, motivational interviewing and family therapy), alongside the development of specialist mental health teams for adolescent and adult ADHD in Ireland, is central to the treatment success for co-morbid adults with ADHD and SUD (Goossensen etal. Reference Goossensen, van de Glind, Carpentier, Wijsen, van Duin and Kooij2006; Riggs etal. Reference Riggs, Levin, Green and Vocci2008; James etal. Reference James, Smyth and Apantaku-Olajide2013). Interventions promoting parental and teacher monitoring, drug education in schools and early interventions assessing, diagnosing and targeting childhood ADHD symptoms have the potential combined to reduce future SUD trends and subsequent treatment service uptakes (van Emmerik-van Oortmerssen etal. Reference van Emmerik-van Oortmerssen, van de Glind, van den Brink and Smit2012). These strategies will have positive impact on the public mental health and addiction service provisions in Ireland.
Acknowledgements
The authors thank Geurt van de Glind, The International Collaboration on ADHD and Substance Abuse (ICASA) Trimbos Institute, Utrecht, The Netherlands, and Rose Kavanagh, Irish National Council of Attention-Deficit Hyperactive Disorder of Support Groups (INCADDS).
Conflict of Interest
None.
