By Gary L. Wenk, Professor of  Psychology, Neuroscience and Molecular Virology, Ohio State University

During Congressional hearings last year, Facebook (FB) CEO Mark Zuckerberg was asked whether he believed there is a connection between children’s declining mental health and FB use. He objected to that statement saying, “I don’t think that the research is conclusive on that.”

Similar reports of obfuscation were offered for many years by the tobacco companies during Congressional hearings in the 1970s when the world’s major tobacco companies claimed that the scientific evidence about the linkage between smoking and disease was inconclusive. Although the scientific evidence to counter Mr. Zuckerberg’s claim is growing, the findings are entirely correlational. Correlation never proves cause-and-effect.

Compulsive FB use, or other variants of social media, has become a common concern. It is a concept that merits further study, but it is not currently an official psychiatric diagnosis.

Those who study FB addiction believe that it may share the symptoms as addiction to cocaine, gambling, or alcohol. The person spend so much time and effort on FB that it negatively affects all areas of their lives. Like alcohol and cocaine, FB addicts withdraw when they attempt to stop and then relapse. FB addiction even shows evidence of tolerance. Like cocaine, nicotine, and alcohol, FB addiction is behaviorally and genetically linked to depression, loneliness, and poor sleep quality.

Which came first, excessive FB use, loneliness, poor sleep quality, or depression?

A recent correlational study of 354 adults, average age 25, investigated the role of poor sleep quality and loneliness in the path from FB addiction to depression. The study reported that poor sleep quality contributed to the association between FB addiction and depression. The authors suggested that poor sleep quality was likely due to the impact of blue light from whatever electrical devices were being viewed and its effects on the circadian rhythm and sleep. The FB addicts in this study slept less and had overall poor sleep quality. Thus, FB use, per se, was not the cause of the depression.

Excessive FB use was also associated with feelings of loneliness, which also reduced sleep quality. Loneliness was positively correlated with the development of depression. Individuals who reported both high levels of FB addiction and loneliness reported the highest risk of depression. In contrast, individuals with low levels of FB addiction and loneliness had the lowest risk of depression. This correlation is interesting but does not prove cause-and-effect.

Their findings suggest that FB (and likely other social media platforms) addiction indirectly affects depression by inducing poor sleep quality. Their results are consistent with previous studies that have also reported that Internet addiction was associated with short sleep duration, insomnia, tendency to sleep late, sleep disturbances, and drowsiness during the day. Mr. Zuckerberg may be correct that FB is most likely not the cause of depression.

The study also reported that loneliness significantly moderated the association between FB addiction and the development of depression symptoms. Some investigations have previously concluded that Internet addiction leads to problems in relationships, increases feelings of loneliness and social isolation, and then creates depression. Whether certain individuals who carry an inherited risk of depression are more vulnerable to Internet addiction remains to be investigated.

Taken together, previous theories and current evidence suggest that the risk of depression and insomnia might be reduced if individuals restrict their use of all social medial and avoid blue light exposure in the evening.

Gary L. Wenk is Professor of Psychology & Neuroscience & Molecular Virology, Immunology and Medical Genetics at the Ohio State University and Medical Center. He is the author of “Your Brain on Food” (3rd Edition, 2019, Oxford University Press)