Internet addiction is a commonly used term for an unofficially defined form of non-substance-based behavioral addiction that centers on a personally and socially damaging pattern of Internet use. A comorbid disorder is a condition that appears at the same time as one or more additional health problems and contributes to a disproportionate worsening of general well-being. In a study published in October 2014 in Rubin Science Magazine, a team of German researchers used a small-scale project to estimate how often people likely affected by Internet addiction also have a second diagnosable mental health problem. Internet Addiction The American Psychiatric Association (APA) \u2014 traditional definer of diagnosable mental illness in the U.S. \u2014 recognizes the existence of behavioral addiction, a form of non-substance-related addiction that produces telltale changes in brain function and behavior that largely mirror the changes found in substance addicts. As of 2014, the APA has only set forth official diagnostic guidelines for one type of behavioral addiction, called gambling disorder. However, the organization has acknowledged the potential existence of Internet addiction and in 2013 tentatively identified possible symptoms of such an addiction under the heading of a condition called Internet gaming disorder. Addiction and mental health organizations in several other countries have also established criteria for identifying people likely affected by diagnosable problems with Internet use. Symptoms commonly included as potential indications of such problems include a partial or total inability to control Internet use, reliance on Internet use to avoid unpleasant emotional states, an increasing need for Internet use, the appearance of withdrawal-like changes in mood when Internet use is not possible, a declining interest in non-Internet related activities and damage to personal and social relationships caused by excessive Internet involvement. Comorbid Disorders Addiction specialists and researchers are well-aware that people dealing with substance abuse and\/or substance addiction often also have at least one other coexisting or comorbid mental health problem. While some of these problems are relatively minor, significant numbers of affected individuals have diagnosable symptoms of severe mental illnesses such as major depression, schizophrenia or panic disorder. Comorbid conditions typically lead to substantially worse outcomes than a person might expect if he or she only had a single health issue to contend with. Potential consequences include a more rapid decline of mental\/physical well-being, a more difficult course of effective treatment and a higher chance of dying at a relatively early age. While comorbidity is a well-known phenomenon in people dealing with substance abuse\/addiction, researchers have less information on the existence of comorbidity in people dealing with non-substance-based behavioral addiction. Is Internet Addiction Comorbid? In the study published in Rubin Science Magazine, researchers from Germany\u2019s Ruhr University Bochum used information gathered from 25 young adult men to estimate how often people likely affected by Internet addiction have a comorbid mental health problem. All 25 of the study participants had significant symptoms of an addictive relationship to Internet use. The researchers used detailed diagnostic interviews with each individual to determine the frequency of separate mental illness and also to determine which types of illness occurred most often. After completing these interviews, they concluded that all of the participants likely dealing with Internet addiction also had diagnosable symptoms of at least one separate mental health problem. Nearly three-quarters (70 percent) of the study participants had symptoms of some form of depression, while the remainder had symptoms of illnesses that included attention deficit hyperactivity disorder (ADHD) and the anxiety disorder known as social phobia or social anxiety disorder. The researchers also looked at the situation from the other end by using interviews with groups of people diagnosed with ADHD or some form of depression to determine how often these individuals have potential symptoms of Internet addiction. They concluded that roughly a quarter of the participants in these interviews had indications of a dysfunctional, addictive relationship to Internet use. The study\u2019s authors note that their results indicate that the rate of comorbid mental health problems found in people affected by Internet addiction may be substantially higher than the rate of comorbid mental health problems found in people affected by alcoholism. They believe that, at least among young men, symptoms of Internet addiction may frequently go unnoticed in people dealing with diagnosable mental illness. Since there is no standard definition for addictive Internet use, the study\u2019s findings must be viewed as tentative.