It may be a writing constraint or decision by the editor to keep the article focused on alcohol and drug use, as addiction to "video games, porn and social medi

It may be a writing constraint or decision by the editor to keep the article focused on alcohol and drug use, as addiction to "video games, porn and social media" may have different treatment approaches or signs of addiction (and would thus significant broaden the article's scope), though I agree with your last two sentences. For example, consider the criteria used to describe the signs of addiction: "You need an increasing amount of alcohol or drugs to feel a buzz or high. You feel an urgency to get the first drink or drug of the day. You experience a loss of interest in other activities and an increased desire to get ‘high’ or ‘buzzed’. You try to quit or cut down on the use of alcohol or drugs but can’t. You will do almost anything to get the drug or alcohol." You might feel an urge for these other addictive habits at the start of the day; experience a loss of interest in other activities; and try to cut down but can't. For the pull to experience an "increasing amount" of the activity for a high, that is plausible for porn (for some users, it's a want for more extreme content), but less so for video games and social media. It's also not immediately obvious—especially when compared to drugs and alcohol—that a user of video games, porn, or social media would "do almost anything" to satisfy the urge. The bottom line is that these behaviours, while addicting, have significant differences when compared to alcohol and drugs. Speaking from past writing experience, these would require the article to significantly broaden its scope, which may not have been possible due to editorial constraints (e.g. word count). It's also plausible that the original article may have been, "The first steps to respond to a potential alcohol or drug addiction," but the editor shortened it to a catchier "How to know if you're addicted."