Does attention-deficit hyperactivity disorder impact the developmental course of drug and alcohol abuse and dependence?

Identifying the facets of impulsivity that explain the relation between ADHD symptoms and substance use in a nonclinical sample

Adults with attention-deficit/hyperactivity disorder (ADHD) are at higher risk to use substances than their nonclinical peers. Increased levels of impulsivity are generally thought to contribute to their increased levels of risk. Impulsivity is a multifaceted construct, however, and little research to date has attempted to identify which facets of impulsivity contribute to the increased rates of substance abuse among individuals with ADHD. The current study examined the relation among ADHD symptom clusters (i.e., hyperactivity/impulsivity and inattention), substance use rates (i.e., alcohol use, nicotine use, and marijuana use), and personality processes associated with impulsive behavior in a group of young adults. Participants were 361 undergraduate students. Both symptom clusters were positively associated with rates of substance use. Specifically, hyperactive/impulsive symptoms were associated with alcohol and nicotine use, and inattentive symptoms were associated with alcohol use. Several pathways from hyperactive/impulsive symptoms to alcohol, nicotine, and marijuana use via specific facets of impulsivity were identified. These findings have implications for understanding the relation between ADHD symptoms and substance use, as well as clinical implications for preventing and treating substance use problems in individuals with symptoms of ADHD.

Sex differences and the interaction of age and sleep issues in neuropsychological testing performance across the lifespan in an ADD/ADHD sample from the years 1989 to 2009

Chart review of population (9 to 80 years) neuropsychological test battery for ADHD diagnosis, questionnaires with multiple responders were evaluated in outpatient setting from 1989-2009. The focus was gender differences across age, diagnostic group (ADHD-Inattentive/ADHD plus), neuropsychological test performance, and reported sleep symptoms over the lifespan. Individuals were assigned to ADHD-I group or ADHD plus group (based upon secondary diagnosis of sleep, behavioral, emotional disturbance); ADHD not primary was excluded (brain insult, psychosis). Among these were 1,828 children (ages 9 to 14), adolescents (ages 15 to 17), and adults (ages 18 and above); 446 children (312 diagnosed ADHD-I), 218 adolescents (163 diagnosed ADHD-I), and 1,163 adults (877 ADHD-I). Sleep was problematic regardless of age, ADHD subtype, and gender. The type and number of sleep problems and fatigue were age dependent. ADHD subtype, gender, fatigue, age, and sleep (sleep onset, unrefreshing sleep, sleep maintenance) were significant variables affecting neuropsychological test performance (sequencing, cognitive flexibility, slow- and fast-paced input, divided attention, whole brain functioning). Findings suggest that ADHD involves numerous factors and symptoms beyond attention, such as sleep which interacts differently dependent upon age.

A comparison of bipolar disorders in children in Italy and the United States

BACKGROUND

The clinical presentation of bipolar disorders, though clearly recognized in adolescents, remains controversial in younger children and across cultures. The aim of this study was to compare the clinical presentation of bipolar disorders in Italian and American children between ages 5 and 12 years.

METHODS

Sixty-seven children from six outpatient programs were enrolled (Italian sample: n=40; American sample: n=28) between January 2010 and June 2011. Children and their parents were interviewed by experienced clinicians using the Washington University in St. Louis Schedule for Affective Disorders and Schizophrenia for School-Age Children-Present, Lifetime Version (WASH-U K-SADS).

RESULTS

Italian children scored significantly higher on ratings of "elevated mood" (p=0.002), whereas American children scored significantly higher on ratings of "flight of ideas" (p=0.001) and "productivity" (p=0.001). Rates of comorbidity were different between groups.

LIMITATIONS

Data were acquired from several sites in Italy as compared to from a single American site. Medication and educational information were not systematically collected. Furthermore, the sample collected may only reflect characteristics of a less severely ill group of bipolar children.

CONCLUSIONS

Our comparison of Italian and American children with early onset bipolar disorders found that the phenotype of bipolar spectrum disorders is largely shared across cultures, although psychiatric comorbidities differed.

Prescribing of drugs for attention-deficit hyperactivity disorder in opioid maintenance treatment patients in Norway

BACKGROUND

Attention-deficit hyperactivity disorder (ADHD) is a risk factor for the development of substance use disorders. Treatment of ADHD with psychostimulants in patients on opioid maintenance treatment (OMT) has been restricted in Norway. We examined the use of prescribed drugs for ADHD in OMT patients and assessed co-medication with other psychotropics.

METHODS

Data were drawn from the nationwide Norwegian Prescription Database (NorPD), which includes all prescriptions filled at pharmacies. The study population included subjects ≥18 years on OMT during 2008-2010.

RESULTS

In 2010, 6,116 patients received OMT and 2.8% of these also received ADHD drugs. This percentage is seven times greater than that in the gender- and age-specific general population of Norway. The prevalence was higher in the youngest patients, while there was no gender difference. Methylphenidate was the most commonly used drug for ADHD in OMT patients, followed by atomoxetine. 60% of OMT patients filled at least one prescription for antidepressants, anxiolytics or hypnotics, and percentages were similar for users and non-users of ADHD drugs.

CONCLUSION

Treatment with ADHD drugs was higher in OMT patients than expected from the general population, but was relatively low compared to the prevalence of ADHD in patients with substance use disorders reported in the literature.

The efficacy of atomoxetine as adjunctive treatment for co-morbid substance use disorders and externalizing symptoms

BACKGROUND

We examined the effect of atomoxetine supplementation in treated-as-usual patients with alcohol, tobacco and other drug dependence (ATOD) and co-morbid externalizing symptoms (ES).

METHOD

Subjects were selected from a substance dependence treatment-cohort and assessed for: (a) high ES counts, (b) maximum prior period of abstinence, (c) quality of life during that period, and (d) shortest time from prior relapse to restarting treatment. Subjects were prescribed atomoxetine and followed up to their first relapse.

RESULTS

Out of 262 subjects screened during the study period (March-April 2008), 18 subjects who fulfilled eligibility criteria were recruited. All subjects were male, with early onset of substance dependence to at least two substances. Atomoxetine treatment led to significant treatment benefits: ES reduction, longer abstinence, shorter turnaround time and better quality of life.

CONCLUSIONS

Atomoxetine has a potential role in the treatment of early onset ATOD patients with ES, as an adjuvant to the standard treatment.

The International ADHD in Substance Use Disorders Prevalence (IASP) study: background, methods and study population

Attention deficit/hyperactivity disorder (ADHD) is an increasingly recognized comorbid condition in subjects with substance use disorders (SUDs). This paper describes the methods and study population of the International ADHD in Substance Use Disorders Prevalence (IASP) study. Objectives of the IASP are to determine the prevalence of ADHD in adult treatment seeking patients with SUD in different countries and SUD populations, determine the reliability and validity of the Adult ADHD Self-report Scale V 1.1 (ASRS) as ADHD screening instrument in SUD populations, investigate the comorbidity profile of SUD patients with and without ADHD, compare risk factors and protective factors in SUD patients with and without a comorbid diagnosis of ADHD, and increase our knowledge about the relationship between ADHD and the onset and course of SUD. In this cross-sectional, multi-centre two stage study, subjects were screened for ADHD with the ASRS, diagnosed with the Conner's Adult ADHD Diagnostic Interview for DSM-IV (CAADID), and evaluated for SUD, major depression, bipolar disorder, anti social personality disorder and borderline personality disorder. Three thousand five hundred and fifty-eight subjects from 10 countries were included. Of these 40.9% screened positive for ADHD. This is the largest international study on this population evaluating ADHD and comorbid disorders.

First-incidence of DSM-IV mood, anxiety and substance use disorders and its determinants: results from the Netherlands Mental Health Survey and Incidence Study-2

BACKGROUND

Prospective studies measuring first-incidence of DSM-IV mood, anxiety and substance use disorders in the general population are rare. We assessed these incidence rates in the Dutch population; and identified baseline sociodemographic, physical and psychopathological variables, and negative changes in sociodemographics and physical health between baseline and follow-up, as determinants of first-onset main categories of disorders.

METHOD

Data are from NEMESIS-2, a representative face-to-face survey including 5303 subjects aged 18-64 interviewed twice (2007-2009; 2010-2012) with the CIDI 3.0.

RESULTS

In three years, 8.86% of adults without prior psychopathology experienced any mental disorder, corresponding with 3.09 cases per 100 person-years. Incidence was highest for anxiety (1.69 per 100 person-years) and mood disorder (1.65), and lowest for substance use disorder (0.97). For the separate disorders, incidence was highest for major depression (1.58), specific phobia (0.79) and alcohol abuse (0.73). For mood and anxiety disorder, incidence rate was higher among women and for substance use disorder it was higher among men. Age was inversely related to all disorder categories. Changes in sociodemographics, like no longer living with a partner and decrease in income, were stronger determinants than the corresponding sociodemographics. Incident mood disorder was predicted by baseline anxiety and substance use disorder, incident anxiety disorder by mood and substance use disorder, and incident substance use disorder by adult ADHD.

LIMITATIONS

Validity of lifetime diagnoses can be questioned because of difficulty of accurate recall. Only determinants of categories of disorders were studied, due to low numbers of incident cases of most separate disorders.

CONCLUSION

First-onset of mental disorders in a 3-year period is not an uncommon phenomenon. Results about determinants of incident disorders are important for prevention and early intervention initiatives aimed at reducing burden of mental disorders.

Attention deficit hyperactivity disorder in cocaine-dependent adults: a psychiatric comorbidity analysis

BACKGROUND AND OBJECTIVES

Attention deficit hyperactivity disorder (ADHD) is highly prevalent among drug abusers. We studied the psychiatric comorbidity and characteristics of cocaine use in relation to the presence of ADHD among patients with cocaine dependence.

METHODS

A total of 200 cocaine-dependent patients attending an Outpatient Drug Clinic participated in the study. A systematic evaluation of ADHD (CAADID-II), the severity of addiction (EuropASI) and other axes I and II psychiatric disorders was made (SCID-I and SCID-II). A descriptive, bivariate, and multivariate analysis of the data was performed.

RESULTS

In the multivariate analysis, the identified risk factors for the development of ADHD were a history of behavioral disorder in childhood (OR: 3.04), a lifetime history of cannabis dependence in the course of life (OR: 2.68), and age at the start of treatment (OR: 1.08). The bivariate analysis showed ADHD to be associated with other factors such as male gender, age at start of cocaine use and dependence, the amount of cocaine consumed weekly, increased occupational alteration, alcohol consumption, general psychological discomfort, depressive disorder, and antisocial personality disorder.

CONCLUSIONS AND SCIENTIFIC SIGNIFICANCE

We conclude that ADHD is associated with increased psychiatric comorbidity and greater severity of addiction.

Attention deficit hyperactivity disorder in a Canadian prison population

Previous research has shown that a significant percentage of offenders are affected by adult attention deficit hyperactivity disorder (ADHD) and its related symptoms, however it is unknown the extent to which this disorder affects federal inmates in Canada and the impact ADHD has on key correctional outcomes. Four hundred and ninety-seven male federal offenders were assessed at intake over a fourteen month period using the Adult ADHD Self-Report Scale (ASRS). Approximately 16.5% scored in the highest range, which is consistent with the clinical threshold for diagnosis for the disorder; a further 25.2% reported sub-threshold symptoms in the moderate range. ADHD symptoms were found to be associated with unstable job history, presence of a learning disability, lower educational attainment, substance abuse, higher criminal risk and need levels, and other mental health problems. ADHD symptoms were also found to predict institutional misconduct. Additionally, offenders with high levels of ADHD symptomatology fared more poorly on release to the community. Implications for institutional behavior management and the need for additional resources and adapted interventions are discussed.

Mental disorders diagnosed in childhood and at-risk mental state in a help-seeking population

AIM

Disorders usually first diagnosed in infancy, childhood or adolescence (DUFD-ICA) may have preceded the onset of psychosis by several years and share some co-morbidity with psychotic disorders, but only a few studies have investigated this aspect. We looked for past or current DUFD-ICA in a sample of first adult psychiatric service users assessed for the presence of an at-risk mental state with the Structured Interview for Psychosis-risk Syndromes (SIPS).

METHODS

We interviewed with the SIPS 159 first-time help seekers (age range 13-30 years) at adult psychiatric services who volunteered to participate in the study. For psychiatric diagnoses, we used the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition-Text Revision. We also assessed retrospectively the presence of DUFD-ICA and administered the Brief Psychiatric Rating Scale (BPRS) and the Global Assessment of Functioning. The sample has been subdivided diagnostically into first-episode psychosis, multiple episode psychosis, ultra-high risk (UHR) and other diagnoses.

RESULTS

The risk for having one of first-episode psychosis, multiple episode psychosis or UHR was over 3.45 higher in the DUFD-ICA-positive history group than in the non-DUFD-ICA. Grouping the UHR with the not full-blown psychosis cases resulted in a further increase of the risk to 4.71. DUFD-ICA-positive participants scored higher than non-DUFD-ICA on the Positive, Negative and Disorganization scales of the SIPS and on several core-psychotic BPRS items.

CONCLUSIONS

A positive history of DUFD-ICA increases the risk of a diagnosis of prodromal or current psychosis at help seeking. Impaired neurodevelopment may be shared among the psychoses and DUFD-ICA.

Differential reward processing in subtypes of adult attention deficit hyperactivity disorder

OBJECTIVES

Abnormalities in reward processing have been found in adolescents and adults with ADHD using the 'Monetary Incentive Delay' (MID) task. However, ADHD groups in previous studies were heterogeneous regarding ADHD subtype, gender and, in part, drug treatment status. This study sought to compare neural activations in the ventral striatum (VS) and prefrontal regions during reward processing in homogenous ADHD subtype groups and healthy adults, using the MID task.

METHODS

In total, 24 drug-naïve, right-handed male adults with ADHD (12 subjects with combined type (ADHD-ct) and 12 subjects with predominantly inattentive (ADHD-it) type ADHD), and twelve healthy right-handed male control subjects were included.

RESULTS

Compared to ADHD-ct and healthy subjects, ADHD-it subjects showed a bilateral ventral striatal deficit during reward anticipation. In contrast, ADHD-ct subjects showed orbitofrontal hyporesponsiveness to reward feedback when compared with ADHD-it and healthy subjects.

CONCLUSIONS

This is the first fMRI study that delineates dysfunctional and subtype-divergent neural and behavioural reward processing in adults with ADHD.

Associations between attention deficit hyperactivity disorder symptom domains and DSM-IV lifetime substance dependence

BACKGROUND AND OBJECTIVES

Most studies of attention deficit hyperactivity disorder (ADHD) in the substance dependence literature have assessed ADHD as a single, categorical entity. This approach limits characterization across the spectrum of ADHD symptomatology and may mask differences across the two core domains of ADHD symptoms-hyperactive-impulsive (HI) and inattention (IN). Further, it is unclear whether relations of HI and IN symptoms to substance dependence extend across drug classes and to the general population.

METHODS

This cross-sectional study investigated associations of lifetime ADHD HI and IN symptom levels to individual classes of lifetime substance dependence (alcohol, nicotine, depressants, opioids, stimulants, cannabis, hallucinogens, polysubstance) in a population-based sample of 34,653 American adults.

RESULTS

HI and IN were associated with the majority of dependence diagnoses in a linear pattern, such that each additional symptom was associated with a proportional increase in odds of dependence. After adjusting for the overlap between symptom domains, both HI and IN uniquely associated with alcohol, nicotine, and polysubstance dependence, but only HI uniquely associated with dependence on illicit substances.

CONCLUSIONS AND SCIENTIFIC SIGNIFICANCE

These findings suggest that individuals in the general population with elevated levels of ADHD (particularly HI) symptoms are at risk for various forms of substance dependence and could benefit from preventive interventions.

Dimensionality, hierarchical structure, age generalizability, and criterion validity of the GAIN's Behavioral Complexity Scale

This study used Rasch measurement model criteria and traditional psychometric strategies to examine key psychometric properties of the Behavioral Complexity Scale (BCS), a widely used measure of externalizing disorders that focuses on attention deficit, hyperactivity, and conduct disorders. With a sample of 7,435 persons being screened for substance use disorders, the BCS was found to (a) be unidimensional, (b) have a hierarchical severity structure, (c) be generalizable to both youths and adults, and (d) meet hypothesized correlations with criterion variables. The BCS performed well as a unidimensional measure. The Rasch severity hierarchy of attention deficit to hyperactivity to conduct disorders provided a perspective that suggested that a dimensional measure could be used as an alternative and, in some ways, as an improvement to categorical diagnosis and common dimensional approaches. The finding of 3 low-severity conduct disorder items also supported a revision of categorical criteria, especially in substance use disorders.

Chronic treatment with extended release methylphenidate does not alter dopamine systems or increase vulnerability for cocaine self-administration: a study in nonhuman primates

Despite the widespread use of stimulant medications for the treatment of attention deficit hyperactivity disorder, few studies have addressed their long-term effects on the developing brain or susceptibility to drug use in adolescence. Here, we determined the effects of chronic methylphenidate (MPH) treatment on brain dopamine (DA) systems, developmental milestones, and later vulnerability to substance abuse in juvenile nonhuman primates. Male rhesus monkeys (approximately 30 months old) were treated daily with either a sustained release formulation of MPH or placebo (N=8 per group). Doses were titrated to achieve initial drug blood serum levels within the therapeutic range in children and adjusted throughout the study to maintain target levels. Growth, including measures of crown-rump length and weight, was assessed before and after 1 year of treatment and after 3-5 months washout. In addition, positron emission tomography scans were performed to quantify binding availability of D2/D3 receptors and dopamine transporters (DATs). Distribution volume ratios were calculated to quantify binding of [¹⁸F]fluoroclebopride (DA D2/D3) and [¹⁸F]-(+)-N-(4-fluorobenzyl)-2β-propanoyl-3β-(4-chlorophenyl)tropane (DAT). Chronic MPH did not differentially alter the course of weight gain or other measures of growth, nor did it influence DAT or D2/D3 receptor availability after 1 year of treatment. However, after washout, the D2/D3 receptor availability of MPH-treated animals did not continue to decline at the same rate as control animals. Acquisition of intravenous cocaine self-administration was examined by first substituting saline for food reinforcement and then cocaine doses (0.001-0.1 mg/kg per injection) in ascending order. Each dose was available for at least five consecutive sessions. The lowest dose of cocaine that maintained response rates significantly higher than saline-contingent rates was operationally defined as acquisition of cocaine reinforcement. There were no differences in rates of acquisition, overall response rates, or cocaine intake as a function of cocaine dose between groups. In an animal model that closely mimics human development; chronic treatment with therapeutic doses of sustained release MPH did not have a significant influence on the regulation of DATs or D2/D3 receptors, or on standard measures of growth. Furthermore, this treatment regimen and subsequent drug washout did not have an impact on vulnerability to cocaine abuse.

The role of conduct disorder in the association between ADHD and alcohol use (disorder). Results from the Netherlands Mental Health Survey and Incidence Study-2

BACKGROUND

Much is unclear about the association between attention-deficit/hyperactivity disorder (ADHD) and alcohol use (disorder). Research on this subject is hindered by the role of conduct disorder (CD). We investigate whether (1) childhood ADHD is associated with higher prevalence and earlier onset of alcohol initiation, regular alcohol use and alcohol use disorder (AUD) (2) CD mediates or modifies this association.

METHODS

Data were derived from the baseline assessment of the Netherlands Mental Health Survey and Incidence Study-2, a general population study. ADHD and CD were assessed among respondents aged 18-44 (n=3309). ADHD, CD, and alcohol use (disorder) were assessed using the Composite International Diagnostic Interview 3.0.

RESULTS

Lifetime prevalence was 2.9% for ADHD, 5.6% for CD, 94.3% for alcohol initiation, 85.7% for regular alcohol use and 19.0% for AUD; mean ages of onset were 6.7, 11.5, 14.8, 16.7 and 19.2 years, respectively. After correction for gender and age, ADHD was associated with a higher prevalence of all three stages of alcohol use, but not with earlier onset of these stages. The association between ADHD and prevalence of AUD was fully explained by a mediating role of CD. CD did not modify the associations between ADHD and prevalence and onset of alcohol use (disorder).

CONCLUSIONS

The mediating role of CD in the association between ADHD and AUD suggests a developmental pathway from ADHD to CD and subsequent AUD. Early interventions in children with ADHD may prevent CD and subsequent onset of AUD.

Patterns of cognitive impairments among heroin and cocaine users: the association with self-reported learning disabilities and infectious disease

This study used data from six neuropsychological measures of executive function (EF) and general intellectual functioning (GIF) administered to 303 regular users of heroin and/or cocaine as indicators in a latent profile analysis (LPA). Results indicated the presence of three profiles: impaired GIF and EF profile (30.8%), intact GIF and EF profile (58.8%), and high GIF/intact EF profile (10.4%). Using a multinomial logistic regression, it was determined that individuals who reported being diagnosed with either a learning disability (LD) and/or attention-deficit/hyperactivity disorder (ADHD) were more likely to be in the impaired GIF and EF profile than other profiles. Results from a logistic regression indicated that the impaired GIF and EF profile was associated with a greater prevalence of past hepatitis B and/or C infection. Implication for harm reduction and treatment programs and the need to take into account individuals with LD and ADHD are discussed.

Language Disabilities, Comorbid Developmental Disorders and Risk for Drug Abuse in Adolescence

This paper deals with research which makes links between developmental problems such as language-learning disorders, attentional disorders, and behaviour disturbance on the one hand, and risk for misuse of alcohol and other drugs (AOD) in adolescence on the other. Poor academic performance is frequently cited as a risk for adolescent AOD misuse, however few workers have critically examined the role of linguistically-based academic sub-skills (e.g., oral and written language competence; strong social skills) which normally contribute to academic success, and hence operate as protective factors with respect to risk for AOD misuse. Studies which specifically address language skills and their association with risk for AOD misuse are reviewed, as are investigations which deal with patterns of comorbidity which are typically evident in clinical populations. Particular emphasis is placed on comorbidities between language-learning difficulties on the one hand, and behavioural or attentional disorders, on the other. It is argued that more explicitly investigating and intervening at the level of core language/social skill competencies might serve to strengthen protective factors in vulnerable groups. It is also noted that comorbid problems need to be considered as important covariates in studies of language disordered children and adolescents, rather than being treated as exclusionary criteria.

A systematic review of global publication trends regarding long-term outcomes of ADHD

There is increased global recognition of attention deficit hyperactivity disorder (ADHD) as a serious medical condition with long-term consequences. Although originally conceived of as a childhood disorder, ADHD is being increasingly recognized in adults. Individual geographic regions may have specific interests and objectives for the study of ADHD. A systematic review of long-term outcomes (LTOs) in ADHD was conducted to evaluate research on ADHD LTOs on a global scale. Studies that were at least 2 years in duration were examined. A total of 351 studies were identified in the final analysis. We identified nine outcomes of interest and classified studies by specific geographical regions, age groups studied and study design by region and over time. Published studies of LTOs in ADHD have increased in all geographical regions over the past three decades, with a peak number of 42 publications in 2008. This rise in publications on ADHD LTOs may reflect a rise in global interest and recognition of consequences and impairment associated with ADHD. Although many world regions have published on ADHD LTOs, the majority of studies have emerged from the US and Canada, followed by Europe. While investigators in the US and Canada were predominantly interested in drug addiction as a LTO, European researchers were more interested in antisocial behavior, and Eastern Asian investigators focused on both of these LTOs as well as self-esteem. Geographical differences in the focus of ADHD LTO studies may reflect regional variations in cultural values. Proportionally fewer prospective longitudinal studies and proportionally more retrospective and cross-sectional studies have been published in more recent decades. Finally, more studies focusing on ADHD in adolescents and adults have been conducted in recent years, and particularly adolescents in Eastern Asia. These changes in basic study design may reflect an increase in the recognition that ADHD is a lifetime chronic disorder. This systematic review analysis of publication trends in ADHD LTOs reflects geographically based interests that change over time.

ADHD in children and adults: diagnosis and prognosis

Attention-deficit hyperactivity disorder (ADHD) is one of the most common neuropsychiatric disorders with childhood onset, having a chronic course associated with high dysfunction and morbidity throughout life. Despite significant advances in our understanding of the neurobiological underpinnings of the disorder, diagnosis of ADHD remains strictly clinical and is based on behavioral symptoms of inattention, impulsivity, and hyperactivity. In this chapter, we review the diagnostic process and current controversies in the diagnosis of ADHD, discuss the clinical presentation of the disorder across the lifespan, and examine the patterns of comorbidity and the longitudinal predictors of outcomes. We conclude by pointing out some of the challenges that need to be addressed in future classifications systems to improve the characterization and validity of the diagnosis of ADHD.

Methylphenidate transdermal system in adults with past stimulant misuse: an open-label trial

OBJECTIVE

This 8-week, open-label trial assessed the efficacy of methylphenidate transdermal system (MTS) in 14 adult individuals diagnosed with ADHD and with a history of stimulant misuse, abuse, or dependence.

METHOD

The primary efficacy endpoint was the Wender-Reimherr Adult ADHD Scale (WRAADS), and secondary efficacy endpoints included the Clinical Global Impression (CGI) ratings and substance abuse as quantified by urine drug screens and self-reported use.

RESULTS

Significant improvements from baseline were found on both the WRAADS and CGI measurements. No abuse of the study medication was observed.

CONCLUSION

The findings suggested that MTS may improve ADHD symptoms in adults with a history of stimulant misuse; however, there were limitations. The study data showed the need for subsequent randomized studies that further explore findings made in this study.

Reliability and validity of self- and other-ratings of symptoms of ADHD in adults

OBJECTIVE

Few studies have examined concordance between raters of ADHD symptoms in adults; there is less information on how well rating scales function in distinguishing adult ADHD from other disorders. This study examined these variables using the Conners Adult ADHD Rating Scales (CAARS).

METHOD

The sample included 349 adults evaluated for attention problems. Correlations and kappa values were calculated using self- and observer-ratings of item-level symptoms; sensitivity, specificity, and discriminant validity of cluster scores in predicting clinician diagnoses were computed for 269 participants.

RESULTS

Item-level concordance rates ranged from slight to fair. Cluster scores demonstrated a poor balance of sensitivity and specificity in predicting ADHD diagnosis; a high percentage of participants with internalizing disorders had scores in the clinical range.

CONCLUSION

Self-and observer- ratings on the CAARS provide clinically relevant data about attention problems in adults, but the instrument does not effectively distinguish between ADHD and other adult psychiatric disorders.

Methylphenidate treatment in adolescent rats with an attention deficit/hyperactivity disorder phenotype: cocaine addiction vulnerability and dopamine transporter function

Appropriate animal models of attention deficit/hyperactivity disorder (ADHD) and drug reinforcement allow investigation of possible underlying biological bases of ADHD and its comorbidity with cocaine addiction. Toward this end, spontaneously hypertensive rats (SHRs) exhibiting an ADHD phenotype were compared with Wistar-Kyoto (WKY) and Wistar (WIS) rats. Initially, 1.5 mg/kg oral methylphenidate or vehicle was administered between postnatal days 28 and 55, and acquisition of visual discrimination learning was examined. After discontinuing adolescent treatments, adult rats were evaluated for cocaine self-administration and dopamine transporter (DAT) function in the prefrontal cortex (PFC) and striatum. During adolescence, SHRs showed deficits in visual discrimination relative to WKY and WIS rats when non-medicated. Methylphenidate improved visual discrimination only in SHRs. Compared with WKY and WIS rats, SHRs with previous methylphenidate treatment acquired cocaine self-administration faster, identified cocaine as a highly efficacious reinforcer by displaying an upward shift in the cocaine dose-response function, and showed the greatest motivation to self-administer cocaine by exhibiting the highest progressive ratio breakpoints. In the PFC, the maximal dopamine uptake (V(max)) at DAT was decreased in SHRs and increased in WKY and WIS rats by previous methylphenidate treatment. The affinity (K(m)) for dopamine at DAT in the PFC was not different between strains, nor was V(max) or K(m) altered in the striatum by previous methylphenidate treatment in any strain. Methylphenidate-induced decreases in dopamine clearance by DAT in the PFC may underlie increased cocaine self-administration in SHRs. These preclinical findings suggest that caution should be exercised when methylphenidate is prescribed for first-time treatment of ADHD in adolescent patients, as cocaine addiction vulnerability may be augmented.

Attention Deficit Hyperactivity Disorder (ADHD) among longer-term prison inmates is a prevalent, persistent and disabling disorder

BACKGROUND

ADHD is a common and disabling disorder, with an increased risk for coexisting disorders, substance abuse and delinquency. In the present study, we aimed at exploring ADHD and criminality. We estimated the prevalence of ADHD among longer-term prison inmates, described symptoms and cognitive functioning, and compared findings with ADHD among psychiatric outpatients and healthy controls.

METHODS

At Norrtälje Prison, we approached 315 male inmates for screening of childhood ADHD by the Wender Utah Rating Scale (WURS-25) and for present ADHD by the Adult ADHD Self-Report Screener (ASRS-Screener). The response rate was 62%. Further, we assessed 34 inmates for ADHD and coexisting disorders. Finally, we compared findings with 20 adult males with ADHD, assessed at a psychiatric outpatient clinic and 18 healthy controls.

RESULTS

The estimated prevalence of adult ADHD among longer-term inmates was 40%. Only 2 out of 30 prison inmates confirmed with ADHD had received a diagnosis of ADHD during childhood, despite most needed health services and educational support. All subjects reported lifetime substance use disorder (SUD) where amphetamine was the most common drug. Mood and anxiety disorders were present among half of subjects; autism spectrum disorder (ASD) among one fourth and psychopathy among one tenth. Personality disorders were common; almost all inmates presented conduct disorder (CD) before antisocial personality disorder (APD). Prison inmates reported more ADHD symptoms during both childhood and adulthood, compared with ADHD psychiatric outpatients. Further, analysis of executive functions after controlling for IQ showed both ADHD groups performed poorer than controls on working memory tests. Besides, on a continuous performance test, the ADHD prison group displayed poorer results compared with both other groups.

CONCLUSIONS

This study suggested ADHD to be present among 40% of adult male longer-term prison inmates. Further, ADHD and coexisting disorders, such as SUD, ASD, personality disorders, mood- and anxiety disorders, severely affected prison inmates with ADHD. Besides, inmates showed poorer executive functions also when controlling for estimated IQ compared with ADHD among psychiatric outpatients and controls. Our findings imply the need for considering these severities when designing treatment programmes for prison inmates with ADHD.

Economic burden and comorbidities of attention-deficit/hyperactivity disorder among pediatric patients hospitalized in the United States

BACKGROUND

This retrospective database analysis used data from the Healthcare Cost and Utilization Project's Nationwide Inpatient Sample (NIS) to examine common primary diagnoses among children and adolescents hospitalized with a secondary diagnosis of attention- deficit/hyperactivity disorder (ADHD) and assessed the burden of ADHD.

METHODS

Hospitalized children (aged 6-11 years) and adolescents (aged 12-17 years) with a secondary diagnosis of ADHD were identified. The 10 most common primary diagnoses (using the first 3 digits of the ICD-9-CM code) were reported for each age group. Patients with 1 of these conditions were selected to analyze demographics, length of stay (LOS), and costs. Control patients were selected if they had 1 of the 10 primary diagnoses and no secondary ADHD diagnosis. Patient and hospital characteristics were reported by cohort (i.e., patients with ADHD vs. controls), and LOS and costs were reported by primary diagnosis. Multivariable linear regression analyses were undertaken to adjust LOS and costs based on patient and hospital characteristics.

RESULTS

A total of 126,056 children and 204,176 adolescents were identified as having a secondary diagnosis of ADHD. Among children and adolescents with ADHD, the most common diagnoses tended to be mental health related (i.e., affective psychoses, emotional disturbances, conduct disturbances, depressive disorder, or adjustment reaction). Other common diagnoses included general symptoms, asthma (in children only), and acute appendicitis. Among patients with ADHD, a higher percentage were male, white, and covered by Medicaid. LOS and costs were higher among children with ADHD and a primary diagnosis of affective psychoses (by 0.61 days and $51), adjustment reaction (by 1.71 days and $940), or depressive disorder (by 0.41 days and $124) versus controls. LOS and costs were higher among adolescents with ADHD and a primary diagnosis of affective psychoses (by 1.04 days and $352), depressive disorder (by 0.94 days and $517), conduct disturbances (by 0.86 days and $1,330), emotional disturbances (by 1.45 days and $1,626), adjustment reaction (by 1.25 days and $702), and neurotic disorders (by 1.60 days and $541) versus controls.

CONCLUSION

Clinicians and health care decision makers should be aware of the potential impact of ADHD on hospitalized children and adolescents.

The impact of medications on quality of life in attention-deficit hyperactivity disorder: a systematic review

Quality of life (QOL) describes an individual's subjective perception of their position in life as evidenced by their physical, psychological and social functioning. Although an established outcome measure in physical health, QOL has more recently become an increasingly important measure in mental health clinical work and research. This article reviews the evidence describing the impact of medications on QOL in attention-deficit hyperactivity disorder (ADHD). Databases were searched for research studies describing the effects of medication on QOL in ADHD: 25 relevant studies were identified. Most (n = 20) of these studies have focused on children and adolescents, and most have investigated a single molecule, atomoxetine (n = 15), with relatively few studies investigating methylphenidate (n = 5), amfetamines (n = 4) and manifaxine (n = 1). These studies support a positive short-term effect of medication on QOL in ADHD for children, adolescents and adults that mirrors, to some extent, the effects of these medications on ADHD symptoms, although with smaller effect sizes. Notwithstanding measurement issues, it will continue to be important that those designing and conducting clinical trials in ADHD, including both pharmacological and non-pharmacological treatments, continue to include measures of QOL as secondary outcome measures. In particular, information about QOL effects in adults and in subjects of all ages taking methylphenidate and amfetamine treatments is urgently needed. The lack of systematic studies of the impact on QOL of psychological therapies, either on their own or in multimodal combinations with medication, is a serious omission that should be urgently addressed.

A placebo-controlled trial of atomoxetine in marijuana-dependent individuals with attention deficit hyperactivity disorder

This study evaluated the effects of atomoxetine on the symptoms of attention deficit hyperactivity disorder (ADHD) and marijuana use in marijuana-dependent adults. In conjunction with motivational interviewing, participants received either atomoxetine (n = 19) or matching placebo (n = 19) for 12 weeks. Participants randomized to atomoxetine had greater improvement in ADHD on the Clinical Global Impression-Improvement scale than participants treated with placebo. No treatment group differences in self-rated ADHD symptoms, overall Wender-Reimherr Adult Attention Deficit Disorder Scale scores, or marijuana use outcomes were noted. These results suggest that atomoxetine may improve some ADHD symptoms but does not reduce marijuana use in this population. 

Effects of atomoxetine on self-reported high-risk behaviors and health-related quality of life in adolescents with ADHD

OBJECTIVE

This study measured the effects of atomoxetine HCl on high-risk behaviors and health-related quality of life in adolescents with attention-deficit/hyperactivity disorder (ADHD), using a subgroup analysis of data from a previous clinical trial.

RESEARCH DESIGN AND METHODS

In the base study, which was conducted at 26 sites in the United States, patients ages 13-16 years were randomized in a double-blind manner to atomoxetine treatment by one of two dose titration schedules for 8 weeks. Patients who responded to treatment were rerandomized to atomoxetine at a daily dose of 0.8 or 1.4 mg/kg for 40 weeks. Patients in the highest-risk quartile for each category of behavior or domain were included and the dosing groups combined.

MAIN OUTCOME MEASURES

Efficacy measures included the Youth Risk Behavior Surveillance (YRBS) and Child Health and Illness Profile - Adolescent Edition (CHIP-AE). The YRBS has six categories of behavior, and the CHIP-AE has six domains. Data for mean change from baseline were analyzed using a last-observation-carried-forward analysis.

RESULTS

A total of 267 patients were randomized, but the high-risk subgroup analyzed in the present study was much smaller (range of n = 5-68 per group). YRBS scores for tobacco use, unhealthful dietary behaviors, inadequate physical activity, and behaviors contributing to unintentional injuries showed statistically significant improvements (p < 0.05) by atomoxetine treatment at Week 8. At the end of the 40-week maintenance period, unhealthful dietary behaviors, inadequate physical activity, and behaviors contributing to unintentional injuries continued to show statistically significant improvements (p < 0.001). When the highest-risk quartile of the CHIP-AE data was analyzed, there were statistically significant improvements on all six domains after atomoxetine treatment at 8 weeks (p < 0.001) and on five of the six domains at 40 weeks (p < or = 0.01).

CONCLUSIONS

Atomoxetine improved self-reported high-risk behaviors and overall health-related quality of life in adolescents with ADHD. Potential limitations of this study include small sample sizes and the fact that it involved a subgroup analysis, which is by nature hypothesis-generating. Further, well-controlled, prospective studies in larger and more heterogeneous ADHD populations, including older patients, are warranted to confirm or reject these findings.

Measuring inappropriate medical diagnosis and treatment in survey data: The case of ADHD among school-age children

We exploit the discontinuity in age when children start kindergarten generated by state eligibility laws to examine whether relative age is a significant determinant of ADHD diagnosis and treatment. Using a regression discontinuity model and exact dates of birth, we find that children born just after the cutoff, who are relatively old-for-grade, have a significantly lower incidence of ADHD diagnosis and treatment compared with similar children born just before the cutoff date, who are relatively young-for-grade. Since ADHD is an underlying neurological problem where incidence rates should not change dramatically from one birth date to the next, these results suggest that age relative to peers in class, and the resulting differences in behavior, directly affects a child's probability of being diagnosed with and treated for ADHD.

Do candidate genes discriminate patients with an autism spectrum disorder from those with attention deficit/hyperactivity disorder and is there an effect of lifetime substance use disorders?

OBJECTIVE

Autism spectrum disorder (ASD) and attention deficit/hyperactivity disorder (ADHD) are developmental disorders that overlap in a number of domains, sometimes complicating clinical distinction between both disorders. Although there is some evidence for a genetic overlap, there are no reports on genes that could differentiate between ASD and ADHD. Furthermore, it is not known whether this genetic overlap is influenced by co-morbid substance use disorders (SUD).

METHODS

A total of 110 adult patients with ASD (n=61) or ADHD (n=49) with or without a lifetime history of SUD participated in a study in which we genotyped polymorphisms in five known candidate genes for (one of) the disorders, i.e. the 5HTTLPR in SLC6A4/5-HTT, rs1800497 (TaqIA C>T) in DRD2, rs7794745 in CNTNAP2, rs1843809 in TPH2, and rs6565113 in CDH13. Genotyping was by Taqman-based analysis or by simple sequence length analysis, where appropriate.

RESULTS

ASD could be differentiated from ADHD with nominal statistical significance by the 5HTTLPR, and the polymorphisms in TPH2 and CNTNAP2. The results were independent of lifetime SUD status.

CONCLUSIONS

Serotonergic genes could prove to play an important role in differentiating between ASD and ADHD, but the results of this exploratory study need replication.

Cardiovascular effects of medications for the treatment of attention-deficit hyperactivity disorder: what is known and how should it influence prescribing in children?

The effective medications currently marketed for attention-deficit hyperactivity disorder (ADHD) have central and peripheral catecholaminergic effects that have been shown to result in statistically significant increases in heart rate and blood pressure. The impact of these medications on serious cardiovascular events in healthy children is unknown, but serious cardiovascular events related to ADHD medications are considered rare. However, children with cardiac pathology may be at greater risk given that increased sympathetic tone has been reported as a causal factor in generating ventricular arrhythmias in adults with coronary artery disease, and physical exercise has been consistently reported as a trigger for increased risk of sudden cardiac death in athletes with underlying cardiovascular disease. ADHD has high co-morbidity with anxiety and depression. These conditions in adults have been reported to have their own cardiovascular risks that may be compounded by interactions resulting from combined pharmacotherapeutic treatments; this interaction has not been evaluated in children. High rates of ADHD reported in subjects with cardiac pathology, as well as in patients with genetic disorders associated with cardiovascular pathology, also suggest that the prevalence of cardiac pathology in ADHD subjects may be greater than that in the general population. Currently, the US FDA and Health Canada require warnings on prescription labeling information for ADHD medications, suggesting that these medications should not generally be used in children or adults with 'known' serious cardiac pathology. Family history, medical history, and physical examination have very low sensitivity for identifying serious cardiac pathology, but this can be markedly enhanced in many instances with the use of electrocardiography, which has high specificity and sensitivity. Identifying and managing underlying cardiovascular pathology may not eliminate the risk of serious cardiovascular events but may increase the safety of using medication frequently required for effective management of ADHD. When the very common and serious consequences from untreated ADHD are also considered in the assessment of risks and benefits, even in the presence of cardiac pathology, it seems that the prescribing of ADHD medications in children should remain unchanged.

Neural circuitry associated with risk for alcohol use disorders

The core features of risk for alcohol use disorders (AUD), including behavioral disinhibition, affective dysregulation, and executive dysfunction, map onto distinct neural circuits that have been found to be abnormal in the offspring of alcohol dependent individuals. Components of the cerebellothalamocortical system and the extended limbic network may provide the underpinnings for the behavioral and emotional dysfunction observed in individuals at heightened risk for AUD. In addition, abnormalities in these structures appear to be altered in individuals with the predisposition for other psychiatric conditions that may share a similar genetic diathesis. This review proposes several neurobehavioral mechanisms of genetic vulnerability that may account for phenotypic characteristics in individuals at risk for AUD.

Treatment seeking adults with autism or ADHD and co-morbid substance use disorder: prevalence, risk factors and functional disability

BACKGROUND

Little is known about Autism Spectrum Disorder (ASD) in adults, especially not about ASD with co-morbid Substance Use Disorder (SUD). We wanted to examine how adults with ASD compare to adults with ADHD on prevalence and risk factors for co-morbid SUD, and on disability levels associated with SUD.

METHODS

We stratified 123 treatment seeking adults with ASD (n=70) or ADHD (n=53), into current, former and no history of SUD (SUD+, SUD(wedge), and SUD-), and conducted interviews to explore associated risk factors and current levels of disability.

RESULTS

Prevalence of co-morbid SUD was higher in ADHD than in ASD in our sample (58% versus 30%, p=0.001). There was no statistically significant difference between ASD and ADHD in risk factors or disability scores. Patients with lifetime SUD started regular smoking earlier in life (OR=5.69, C(95%) 2.3-13.8), reported more adverse family events (OR=2.68; CI(95%) 1.2-6.1), and had more parental SUD (OR=5.36; CI(95%) 1.0-14.5). Disability scores were significantly lower in SUD- and SUD(wedge) groups compared to the SUD+ group.

DISCUSSION

These findings suggest that ASD and ADHD share similar risk factors for SUD. High disability in ASD and ADHD with SUD may normalize after prolonged abstinence. Early onset of SUD was not associated with more severe disability scores than later onset. Results suggest that a subgroup of patients with former SUD may have a higher level of functioning before the onset of SUD in comparison to those without lifetime SUD.

The quality of life of children with attention deficit/hyperactivity disorder: a systematic review

Quality of life (QoL) describes an individual's subjective perception of their position in life as evidenced by their physical, psychological, and social functioning. QoL has become an increasingly important measure of outcome in child mental health clinical work and research. Here we provide a systematic review of QoL studies in children and young people with attention deficit hyperactivity disorder (ADHD) and address three main questions. (1) What is the impact of ADHD on QoL? (2) What are the relationships between ADHD symptoms, functional impairment and the mediators and moderators of QoL in ADHD? (3) Does the treatment of ADHD impact on QoL? Databases were systematically searched to identify research studies describing QoL in ADHD. Thirty six relevant articles were identified. Robust negative effects on QoL are reported by the parents of children with ADHD across a broad range of psycho-social, achievement and self evaluation domains. Children with ADHD rate their own QoL less negatively than their parents and do not always seeing themselves as functioning less well than healthy controls. ADHD has a comparable overall impact on QoL compared to other mental health conditions and severe physical disorders. Increased symptom level and impairment predicts poorer QoL. The presence of comorbid conditions or psychosocial stressors helps explain these effects. There is emerging evidence that QoL improves with effective treatment. In conclusion, ADHD seriously compromises QoL especially when seen from a parents' perspective. QoL outcomes should be included as a matter of course in future treatment studies.

Atomoxetine treatment in adolescents with attention-deficit/hyperactivity disorder

INTRODUCTION

This study compared two atomoxetine titration dosing schedules and two atomoxetine maintenance doses for treating adolescent attention-deficit/hyperactivity disorder (ADHD) inattention and hyperactivity/impulsivity.

METHODS

Adolescents (N = 267) were randomized to a slow or fast titration schedule. Patients who responded continued on a 40-week maintenance treatment, randomized to either 0.8 or 1.4 mg/kg/day.

RESULTS

During the acute period, significant benefit was demonstrated with both titration schedules on the ADHD Rating Scale total score. Although patients in both groups maintained benefit relative to week 0, statistically significant loss of benefit was found for patients maintained on 0.8 mg/kg/day but not on 1.4 mg/kg/day. A similar pattern was observed on the Clinical Global Impressions-ADHD-Severity scores and Life Participation Scale for ADHD-Child Version scores. Mean grades for most subjects improved for patients in both maintenance treatment groups although most improvements were not statistically significant.

CONCLUSIONS

In adolescents with ADHD, treatment benefit at 8 weeks was better maintained long-term with 1.4 mg/kg/day than with 0.8 mg/kg/day. Improvement in adaptive functioning and age-appropriate developmental function was also demonstrated. Atomoxetine 0.8 and 1.4 mg/kg/day were equally well tolerated.

CLINICAL TRIALS REGISTRY

Maintenance of benefit with atomoxetine hydrochloride in adolescents with ADHD, NCT00191035.

Childhood and adolescent hyperactivity-inattention symptoms and academic achievement 8 years later: the GAZEL Youth study

BACKGROUND

Children with attention deficit/hyperactivity disorder (ADHD) are at risk of negative academic outcomes. However, relatively few studies in this area have been based on long-term longitudinal designs and community-based settings. This study examined the link between childhood hyperactivity-inattention symptoms (HI-s) and subsequent academic achievement in a community setting, controlling for other behavioural symptoms, socio-economic status (SES) and environmental factors at baseline.

METHOD

The sample consisted of 1264 subjects (aged 12 to 26 years at follow-up) recruited from the longitudinal GAZEL Youth study. Psychopathology, environmental variables and academic outcomes were measured through self-reports. Multivariate modelling was performed to evaluate the effects of childhood HI-s and other risk factors on academic achievement 8 years later.

RESULTS

HI-s independently predicted grade retention [adjusted odds ratio (OR) 3.58, 95% confidence interval (CI) 2.38-5.39], failure to graduate from secondary school (adjusted OR 2.41, 95% CI 1.43-4.05), obtaining a lower-level diploma (adjusted OR 3.00, 95% CI 1.84-4.89), and lower academic performance. These results remained significant even after accounting for school difficulties at baseline. Negative academic outcomes were also significantly associated with childhood symptoms of conduct disorder (CD), even after accounting for adjustment variables.

CONCLUSIONS

This longitudinal survey replicates, in a general population-based setting, the finding of a link between HI-s and negative academic outcomes.

Issues in the management of patients with complex attention-deficit hyperactivity disorder symptoms

Patients with attention-deficit hyperactivity disorder (ADHD) exhibit a wide range of symptoms related to functional impairment. Psychiatric comorbidities are highly prevalent among these patients, often emerging at an early age and persisting (or reoccurring) into adulthood. Among the most common types of comorbidities in children and adults are disruptive behaviour disorders such as oppositional defiant disorder and conduct disorder, mood disorders, anxiety disorders, and substance use disorders. The heterogeneous clinical presentation of ADHD, which also changes with maturation into adulthood, may often obscure the presence of psychiatric comorbidity. Co-occurring disorders frequently go undetected and lead to negative effects on psychosocial and long-term functional outcomes. As with uncomplicated ADHD, medication therapy combined with psychosocial interventions may be necessary. With comorbid disorders, two or more medications may be considered to appropriately manage both ADHD and the comorbid disorder. However, there are few studies that discuss combination medication treatments and there are no current US FDA-approved combined treatments for ADHD and comorbid conditions. This raises significant challenges and risks for poor tolerability and drug-drug interactions. Nevertheless, identification and appropriate treatment must be given a high priority for these highly vulnerable patients to derive optimal benefits from treatment.

[Neuro-enhancement from an addiction specialist's viewpoint]

The use of medications to enhance performance in healthy individuals is increasingly being propagated even by neuroscientists under such colorful terms as"neuro-enhancement". A large number of medications, including psychostimulants have been advocated in this context. Recent data from the German health insurance company DAK indicate that a number of employees already take medications to fulfill their professional needs and enhance performance. The use of new drugs in the healthy has even been advocated by prominent neurobiologists in a commentary in a recent edition of Nature. There are a number of ethical objections to this use and there is an apparent risk of addiction. To date German psychiatrists have surprisingly not been outspoken on this issue. The author would like to make an emphatic plea against"brain doping" in healthy individuals.

Differences in impulsivity on a delay-discounting task predict self-administration of a low unit dose of methylphenidate in rats

There is controversy about the abuse liability of methylphenidate (MPH) in humans, and MPH has yet to be established fully as a reinforcer in rats. The present experiment examined whether intravenous MPH served as a reinforcer in rats, and how individual differences in impulsivity impacted MPH self-administration. Rats were exposed to a delay-discounting procedure, and then were implanted with an intravenous catheter to assess self-administration of 0.56 mg/kg/infusion MPH at different fixed ratio values. Self-administration rates of different MPH doses (0.03-1.0 mg/kg/infusion) were also examined. Both high and low impulsive rats acquired MPH self-administration at the same rate. All rats pressed more on the active lever than the inactive lever regardless of MPH dose, and pressed more for MPH than for saline. High impulsive rats self-administered more MPH than low impulsive rats at a low unit dose (0.1 mg/kg/infusion), though not at higher doses, indicating that individual differences in impulsive choice influence the dose-dependent reinforcing effects of MPH.

The interaction between the dopamine transporter gene and age at onset in relation to tobacco and alcohol use among 19-year-olds

Recent evidence suggests that heterogeneity in the age at onset could explain the inconsistent findings of association studies relating the dopamine transporter (DAT1) gene with alcohol and nicotine consumption. The aim of this study was to examine interactions between two DAT1 polymorphisms and different initiation ages with regard to alcohol and tobacco consumption levels and dependence. Two hundred and ninety-one young adults (135 males, 156 females) participating in the Mannheim Study of Children at Risk were genotyped for the 40-bp variable number of tandem repeats (VNTR) and rs27072 polymorphisms of DAT1. Age at initiation was assessed at age 15 and 19 years. Information about current alcohol and tobacco consumption was obtained at age 19 years using self-report measures and structured interviews. Results suggest that age at onset of intensive consumption moderated the association of the DAT1 gene with early adult substance use and dependence, revealing a DAT1 effect only among individuals homozygous for the 10r allele of the 40-bp VNTR who had started daily smoking or being intoxicated early in life. Equally, carriers of the T allele of the rs27072 polymorphism reporting an early age at first intoxication showed higher current alcohol consumption at age 19 years. In contrast, no interaction between rs27072 and the age at first cigarette with regard to later smoking was observed. These findings provide evidence that the DAT1 gene interacts with an early heavy or regular drug exposure of the maturing adolescent brain to predict substance (ab)use in young adulthood. Further studies are required to confirm these findings.

Plasma and brain concentrations of oral therapeutic doses of methylphenidate and their impact on brain monoamine content in mice

Methylphenidate is a frequently prescribed stimulant for the treatment of attention deficit hyperactivity disorder (ADHD). An important assumption in the animal models that have been employed to study methylphenidate's effects on the brain and behavior is that bioavailability of methylphenidate in the animal models reflects that in human subjects. From this perspective, the dose and route of administration of methylphenidate assume critical importance because both these factors likely influence rate of uptake, plasma and brain concentrations of the drug. In the present study, plasma and brain concentrations of d- and l-methylphenidate and d- and l-ritalinic acid were measured in 2-month old mice (equivalent to young adulthood in humans) following a single oral administration of a racemic mixture. Our data show that oral administration of 0.75 mg/kg dose produced within 15 min, plasma levels of d-methylphenidate that correspond to the clinically effective plasma levels in human subjects (estimated to be 6-10 ng/ml). Brain concentrations of d- and l-methylphenidate tended to exceed their plasma concentrations, while the plasma concentrations of d- and l-ritalinic acid exceeded their brain concentrations. A single oral administration at 0.75 mg/kg dose increased dopamine content of the frontal cortex within 1 h, without producing statistically significant changes in serotonin or noradrenaline contents. Striatal monoamine levels remained unaltered. These data highlight disparities between plasma and brain concentrations of methylphenidate and its metabolites following oral administration and illustrate brain region- and monoamine-specific changes produced by the low oral dose of methylphenidate.

Genetic and non-genetic influences on the development of co-occurring alcohol problem use and internalizing symptomatology in adolescence: a review

AIMS

Alcohol problem use during adolescence has been linked to a variety of adverse consequences, including cigarette and illicit drug use, delinquency, adverse effects on pubertal brain development and increased risk of morbidity and mortality. In addition, heavy alcohol-drinking adolescents are at increased risk of comorbid psychopathology, including internalizing symptomatology (especially depression and anxiety). A range of genetic and non-genetic factors have been implicated in both alcohol problem use as well as internalizing symptomatology. However, to what extent shared risk factors contribute to their comorbidity in adolescence is poorly understood.

DESIGN

We conducted a systematic review on Medline, PsycINFO, Embase and Web of Science to identify epidemiological and molecular genetic studies published between November 1997 and November 2007 that examined risk factors that may be shared in common between alcohol problem use and internalizing symptomatology in adolescence.

FINDINGS

Externalizing disorders, family alcohol problems and stress, as well as the serotonin transporter (5-HTT) S-allele, the monoamine oxidase A (MAOA) low-activity alleles and the dopamine D2 receptor (DDR2) Taq A1 allele have been associated most frequently with both traits. An increasing number of papers are focusing upon the role of gene-gene (epistasis) and gene-environment interactions in the development of comorbid alcohol problem use and internalizing symptomatology.

CONCLUSIONS

Further research in adolescents is warranted; the increasing availability of large longitudinal genetically informative studies will provide the evidence base from which effective prevention and intervention strategies for comorbid alcohol problems and internalizing symptomatology can be developed.

Assessing the value of atomoxetine in treating children and adolescents with ADHD in the UK

BACKGROUND

Economic evaluation of healthcare technologies is becoming increasingly relevant, enabling decision makers to assess and compare treatments within the context of costs and outcomes. Moreover, it is increasingly important for clinicians and prescribers to have some understanding of economic evaluation. For attention-deficit/hyperactivity disorder (ADHD), economic evaluations have largely focused on pharmacotherapy, and results indicate that such treatments are cost-effective compared with other interventions.

AIMS

This review provides an overview of ADHD, its consequences and pharmacotherapy; describes the principles of health economic analysis, health-related quality of life (HRQL) and a cost-effectiveness model of atomoxetine for ADHD treatment; and outlines guidance from the National Institute for Health and Clinical Excellence on ADHD pharmacotherapy.

METHODS

The cost-effectiveness of atomoxetine for children with ADHD in the UK was compared with treatment alternatives using an economic model with Markov processes. The model evaluated atomoxetine in five patient subgroups according to treatment history and comorbidities precluding stimulants. Incremental cost per quality-adjusted life-year (QALY) was calculated and compared between treatment algorithms. The Markov process incorporated 18 health states, representing a range of outcomes across the treatments. Utility values were derived from a survey of 83 parents of children with ADHD, and treatment efficacy and safety were based on a review of controlled clinical trials and literature, and validated by international experts. Costs and outcomes were estimated using Monte Carlo simulation over 1-year.

RESULTS

Atomoxetine was a cost-effective treatment across the whole ADHD population, with incremental cost-effectiveness ratios ranging from pound 11,500 to pound 15,900 per QALY, compared with alternative pharmacotherapies, which are within UK and rest of Europe acceptability limits. Higher utility values achieved treating ADHD with atomoxetine, compensate for the relatively higher acquisition cost compared with stimulants.

CONCLUSIONS

Atomoxetine is cost-effective and may have advantages over stimulants, including benefits to HRQL and no abuse liability and is the only treatment in the UK licensed for continued treatment into adulthood in adolescents who have shown a response from treatment.

Pathways from adolescent parent-child conflict to substance use disorders in the fourth decade of life

This 24-year community longitudinal study provides important information regarding parent-child conflict in adolescence (mean ages 14-16), vulnerable personality attributes and peer deviance in the twenties (mean age 22), and marital conflict and partner's illicit drug use in the late twenties and early thirties (mean ages 27-32) as related to a later diagnosis of substance use disorders (SUDs) in the thirties (mean ages 32-37). A community-based sample was interviewed between 1975 and 2007. Results based in structural equation modeling indicated that a weak parent-child bond was related to the development of drug-conducive personality traits, which was associated with the selection of drug-using peers and partners, which in turn, predicted SUDs. Both peer deviance and partner's illicit drug use had the greatest effects on SUDs. The findings should aid in formulating prevention and treatment programs targeting specific risk factors in adolescents, young adults, and adults.

Drug abuse and hepatitis C infection as comorbid features of HIV associated neurocognitive disorder: neurocognitive and neuroimaging features

Substance abuse and co-infection with hepatitis C (HCV) are two highly relevant determinants of neurocognitive and neuroimaging abnormalities associated with HIV. Substance abuse and HCV are common in the HIV population and there is increasing evidence that the CNS is directly compromised by these comorbid conditions via additive or synergistic processes. In this article we review the current literature regarding mechanisms of neuronal injury as well as the neuropsychological and neuroimaging signatures associated with substance abuse and HCV status among HIV patients. We discuss specific methodological challenges and threats to validity associated with studies of HIV and comorbid substance use disorders or HCV and review potential strategies for minimizing their confounding effects. Efforts to understand the interactions between HIV, substance abuse and HCV co-infection will lead to more complete models of neuropathogenesis of HIV and a greater understanding of the variability in neuropsychological expression of HIV Associated Neurocognitive Disorder.