Analysis of the Joshua Grubbs study: “Self-identification as a pornography addict: examining the roles of pornography use, religiousness, and moral incongruence (Grubbs et al., 2019)
Contrary to spin, this is the first Joshua Grubbs study to correlate any variable with “believing oneself to be porn addict”
In the last few years Dr. Joshua Grubbs has authored a rash of studies correlating porn users’ religiosity, hours of porn use and moral disapproval with the total score on his 9-item questionnaire “The Cyber Pornography Use Inventory” (CPUI-9). In an strategic decision that has lead to much confusion and agenda-drive spin, Grubbs refers to a subject’s total CPUI-9 score as “perceived pornography addiction.” Substituting the inappropriate “perceived addiction” for “Total CPUI-9 score” gives the false impression that the CPUI-9 magically assesses the degree to which a subject merely “believes” he is addicted (rather than assessing the signs & symptom of actual addiction). No questionnaire can do that, and certainly not the CPUI-9. This fact is lost in translation in the Grubbs studies and tweets due to the frequent repetition of the misleading descriptor “perceived addiction” instead of the accurate, spin-free label: “the CPUI-9 total score.”
The CPUI-9 is below. (Each question is scored using a Likert scale of 1 to 7, with 1 being “not at all,” and 7 being “extremely.”) There are two keys for understanding the games being played:
(1) Only question #1 assesses self-identification as a porn addict, which means the CPUI-9 does not assess perceived pornography addiction.
(2) The 3 Emotional Distress questions (assessing guilt & shame) skew the results so that religious porn users score far higher. Guilt and shame questions of this type are not found in any other type of addiction assessment.
Perceived Compulsivity Section
- I believe I am addicted to Internet pornography.
- I feel unable to stop my use of online pornography.
- Even when I do not want to view pornography online, I feel drawn to it
Access Efforts Section
- At times, I try to arrange my schedule so that I will be able to be alone in order to view pornography.
- I have refused to go out with friends or attend certain social functions to have the opportunity to view pornography.
- I have put off important priorities to view pornography.
Emotional Distress Section
- I feel ashamed after viewing pornography online.
- I feel depressed after viewing pornography online.
- I feel sick after viewing pornography online.
As you can see, the CPUI-9 cannot distinguish between actual porn addiction and “belief” in porn addiction. Subjects never “labeled themselves as porn addicts” in any Grubbs study. They simply answered the 9 questions above, and earned a total score, which Grubbs inaccurately labels “perceived porn addiction”.
With lazy journalists and the unknowing public believing that Grubbs’s studies assessed ‘belief in porn addiction”, the table was set for generating skewed results
Dr. Grubbs set out to prove that religiosity was the main predictor of “believing yourself addicted to porn.” He and his team of researchers surveyed 3 rather large, diverse samples (male, female, etc.). This time, however, he didn’t rely on his CPUI-9, which includes 3 “guilt and shame/emotional distress” questions not normally found in addiction instruments – and which skew its results, causing religious porn users to score higher and non-religious users to score lower than subjects do on standard addiction-assessment instruments. Instead, the Grubbs team asked 2 direct yes/no questions of porn users (“I believe that I am addicted to internet pornography.” “I would call myself an internet pornography addict.”), and compared results with scores on a “moral disapproval” questionnaire.
After nine years and multiple CPUI-9 based studies, Grubbs finally correlated “believing oneself addicted to porn” to his usual set of variables: “hours of porn use”, “religiosity”, and “moral disapproval of porn use”. The current Grubbs study found that “self-identification as a pornography addict” correlates most strongly with hours of porn use, far less with moral disapproval, and not at all with religiosity.
The 3 Emotional Distress questions badly skew the results of every CPUI-9 study
Here are a few of the headlines birthed from that study:
- Watching Porn Is OK. Believing In Porn Addiction Is Not
- Perceived Addiction To Porn Is More Harmful Than Porn Use Itself
- Believing You Have Porn Addiction Is the Cause of Your Porn Problem, Study Finds
In the CPUI-9 studies, “religiosity” correlates with Total CPUI-9 scores.
What correlations did the Grubbs studies actually report? Total CPUI-9 scores were related to religiosity (see next section as to why that is), but also related to “hours of porn viewed per week.” In some Grubbs studies a slightly stronger correlation occurred with religiosity, in others a stronger correlation occurred with hours of porn use.
The media grabbed onto the correlation between religiosity and total CPUI-9 scores (now misleadingly labeled “perceived addiction”), and in the process journalists morphed the finding into “religious people only believe they’re addicted to porn.” The media ignored the just-as-strong correlation between CPUI-9 scores and hours of porn use, and pumped out hundreds of inaccurate article…….
Put simply – porn addiction was associated with psychological distress (as was hours of porn use). This was a longitudinal study, and it found that this association between porn use and psychological distress held steady for a year.
No matter how misleading, “perceived pornography addiction” appealed to the mainstream and spread across the media. Everyone assumed Grubbs had figured out a way to distinguish “addiction” and “belief in addiction.” But he hadn’t. He had just given a misleading title to his porn use inventory, the CPUI-9. Nevertheless, articles based on various CPUI-9 studies summed up these findings as:
- Believing in porn addiction is the source of your problems, not porn use itself.
- Religious porn users are not really addicted to porn (even if they score high on the Grubbs CPUI-9) – they just have shame.
Even practitioners were easily misled, because some clients really do believe their porn use is more destructive and pathological than their therapists think it is. These therapists assumed the Grubbs test somehow isolated these mistaken clients when it didn’t.
As the saying goes, “The only cure for bad science is more science.” Faced with thoughtful skepticism about his assumptions, and reservations about the unfounded claims that his CPUI-9 instrument could indeed distinguish “perceived pornography addiction” from genuine problematic porn use, Dr. Grubbs did the right thing as a scientist. He pre-registered a study to test his hypotheses/assumptions directly. Pre-registration is a sound scientific practice that prevents researchers from changing hypotheses after collecting data.
The results contradicted both his earlier conclusions and the meme (“porn addiction is just shame”) that the press helped to popularize.
Dr. Grubbs set out to prove that religiosity was the main predictor of “believing yourself addicted to porn.” He and his team of researchers surveyed 3 rather large, diverse samples (male, female, etc.): Who’s a Porn Addict? Examining the Roles of Pornography Use, Religiousness, and Moral Incongruence. (He posted the results online, although his team’s paper has not yet been formally published).
This time, however, he didn’t rely on his CPUI-9 instrument. The CPUI-9 includes 3 “guilt and shame/emotional distress” questions not normally found in addiction instruments – and which skew its results, causing religious porn users to score higher and non-religious users to score lower than subjects do on standard addiction-assessment instruments. Instead, the Grubbs team asked 2 direct yes/no questions of porn users (“I believe that I am addicted to internet pornography.” “I would call myself an internet pornography addict.”), and compared results with scores on a “moral disapproval” questionnaire.
Directly contradicting his earlier claims, Dr. Grubbs and his research team found that believing you are addicted to porn correlates most strongly with daily hours of porn use, not with religiousness. As noted above, some of Grubbs studies also found that hours of use was a stronger predictor of “perceived addiction” than religiosity. From the new study’s abstract:
In contrast to prior literature indicating that moral incongruence and religiousness are the best predictors of perceived addiction [using the CPUI-9], results from all three samples indicated that male gender and pornography use behaviors were the most strongly associated with self-identification as a pornography addict.
Being male is also strongly predictive of self-labeling as “addicted.” Rates of male porn users who answered “yes” to one of the “addicted” questions ranged from 8-20% in the new study’s samples. These rates are consistent with other 2017 research (19% of college males addicted). Incidentally, this study on male porn users reported problematic use rates of 27.6%, and this study reported that 28% of male porn users evaluated met the threshold for problematic use.
In short, there is widespread distress among some of today’s porn users. High rates of problematic use suggest that the World Health Organization’s proposed diagnosis of “Compulsive sexual behavior disorder” (in the ICD-11 beta draft) is genuinely needed.
Based on their results, Dr. Grubbs and his co-authors advise that, “mental and sexual health professionals should take the concerns of clients identifying as pornography addicts seriously.”