Obsessive compulsive disorder and addiction
It's true that having Obsessive-Compulsive Disorder (OCD) increases an individual's chances of developing an addiction. In arguing against the concept of behavioral addictions, including porn addiction, skeptics often claim that porn addiction is a 'compulsion' not an 'addiction'. That addiction is "like" OCD. When further pressed as to how a 'compulsion to use X' differs (physiologically) from an 'addiction to X', a common comeback by these uninformed skeptics is that "Behavioral addictions are simply OCD." Not true. Research demonstrates that addictions differ from OCD in many substantive ways. In fact, the DSM-5 has separate categories for OCD and behavioral addictions, so its experts realize that the two conditions are physiologically different. An excerpt from this 2016 review sums it up:
Obsessive-compulsive spectrum disorders have been considered to conceptualize sexual compulsivity (40) because some studies have found individuals with hypersexual behavior are on the obsessive-compulsive disorder (OCD) spectrum. OCD for hypersexual behavior is not consistent with DSM-5 (1) diagnostic understandings of OCD, which exclude from the diagnosis those behaviors from which individuals derive pleasure. Although obsessive thoughts of the OCD type often have sexual content, the associated compulsions performed in response to the obsessions are not carried out for pleasure. Individuals with OCD report feelings of anxiety and disgust rather than sexual desire or arousal when confronted with situations triggering obsessions and compulsions, with the latter being performed only to quell uneasiness the obsessive thoughts arouse. (41)
In most of the studies listed in the child pages below, researchers compared substance addictions with gambling addiction because gambling addiction is the only behavioral addiction so far officially recognized in the new DSM-5.