Smoking, Depression in Parents Linked with ADHD in Children

Parental smoking and depression are associated with the likelihood of a child being diagnosed with attention-deficit hyperactivity disorder (ADHD), according to a Korean study published in Asia Pacific Psychiatry.

For the study, investigators from Kyungpook National University, in South Korea analyzed data from The Korea National Health and Nutrition Examination Survey (KNHANES), which contains data on approximately 10,000 Koreans per year since 1998. The survey includes questions about quality of life, socio-economic status, diet, health behaviors, clinical profiles, and more.

Data captured from 23,561 children and adolescents between the years 2005 and 2014 were analyzed for the AP Psychiatry study. Instead of genetic risk factors, the investigators focused on questions that revealed information about a child’s environment and possible environmental risk factors such as demographics, obesity, household income, parental age, depression in adults in the household, and exposure to environmental smoke at home. The team then reviewed the children’s diagnoses for ADHD.

The results of the analyses revealed that parental depression (either parent) and the total amount of smoking adults in the household were associated with an increased risk of ADHD in the children. “Specifically, a paternal smoking amount of over 15 cigarettes per day had a significant association with children's ADHD after adjustment for the father's education level and depression,” the authors wrote.

The investigators postulated that this exposure to smoke in the environment could “cause unhealthy activation of nicotinic acetylcholine receptors (nAChR) [in the children,] which is likely to modulate synaptic plasticity and alter cellular, physiological, and behavioral processes during the critical period of brain development.” They added that the impact of environmental smoke could be also related to epigenetics.

Limitations of the study include that the data were based on self-reports, including self-reported ADHD diagnosis. As such, the investigators emphasized that they could not draw any conclusions about the likelihood of risk factor variables causing ADHD. They hope future studies will investigate any association between the variables and age of initial diagnosis of ADHD as well as treatment methods.

Public health campaigns targeting parental behaviors may be important tools to address ADHD, according to the investigators. “The impact on quality of life, difficulty in disease detection in the early phase, and the financial burden posed by ADHD can be curbed through provision of public support and training program to parents, which could help prevent ADHD occurrence at an early stage in children,” study authors wrote. Potential actions recommended by the investigators include “stop smoking” campaigns and public health care programs to help individuals recognize depression in themselves.