Examining the nature of the association between attention-deficit hyperactivity disorder and nicotine dependence: a familial risk analysis

Comorbidity of Adult ADHD and Its Subtypes With Substance Use Disorder in a Large Population-Based Epidemiological Study

Objective: The objective of the study is to explore the role and possible substance preference in ADHD and subtypes in substance use disorder (SUD). Method: Using self-report data on ADHD Diagnostic and Statistical Manual of Mental Disorders (4th ed.; DSM-IV) symptoms and SUD (alcohol, illicit drugs, and nicotine) in 18,167 Swedish twins, aged 20 to 45 years, we obtained odds ratios (OR) from mixed effect logistic regression, controlling for age, sex, education, and nonindependence of twin data. Results: Increased ADHD symptoms were significantly associated with increased odds for all SUD. ORs ranged between 1.33 for regular nicotine (95% confidence interval [CI] = [1.12, 1.59]); 2.54 for multiple drug use (95% CI = [2.00, 3.23]), and 3.58 for alcohol dependence (95% CI = [2.86, 4.49]). Conclusion: ADHD symptoms and subtypes in the population are associated with increased risks for all SUD outcomes, with no difference between ADHD subtypes, no substance preference, and no sex differences for the comorbidity. Clinicians need to consider ADHD evaluation and treatment as part of management of SUD in adults.

A Review of Impact of Tobacco Use on Patients with Co-occurring Psychiatric Disorders

Consumption of tobacco has been a worldwide problem over the past few decades due to the highly prevalent tobacco-attributable complications. Tobacco use has also been found to be more prevalent in patients with psychiatric disorders. Therefore, we conducted this review about the impact of tobacco use on co-occurring psychiatric disorders. Various facets of this interaction between tobacco use among those with co-occurring psychiatric disorders have been explored. It has been found that people with psychiatric disorders have a higher chance of currently smoking tobacco and lesser chance of cessation. Tobacco use and mental disorders continue to share a complex relationship that has been further evolving after the change in the pattern of tobacco use and also the advent of newer modalities of treatment. However, at the same time, it is believed that cessation of smoking may lead to improvement in the symptoms of mental illness.

Attention-deficit/hyperactivity disorder and risk for substance use disorders in relatives

BACKGROUND

Previous research indicates that attention-deficit/hyperactivity disorder (ADHD) is highly associated with substance use disorders (SUD). However, these studies have failed to clarify the nature of the overlap. The main aim of this study was to explore whether the overlap between ADHD and SUD could be explained by shared genetic and environmental factors or by harmful effects of ADHD medication.

METHODS

We employed a matched cohort design across different levels of family relatedness recorded from 1973-2009. By linking longitudinal Swedish national registers, 62,015 ADHD probands and first-degree and second-degree relatives were identified and matched 1:10 with control subjects without ADHD and their corresponding relatives. Any record of SUD was defined by discharge diagnoses of the International Classification of Diseases or a purchase of any drug used in the treatment of SUD.

RESULTS

First-degree relatives of ADHD probands were at elevated risk for SUD (odds ratios 2.2 and 1.8) compared with relatives of control subjects. The corresponding relative risk in second-degree relatives was substantially lower (odd ratios 1.4 and 1.4). The familial aggregation patterns remained similar for first-degree and second-degree relatives after excluding individuals with coexisting disorders such as schizophrenia, bipolar disorder, depression, and conduct disorder.

CONCLUSIONS

Our findings suggest that the co-occurrence of ADHD and SUD is due to genetic factors shared between the two disorders, rather than to a general propensity for psychiatric disorders or harmful effects of ADHD medication.