Co-dependency is commonly defined as "an emotional and behavioural condition that affects an individual's ability to have a healthy, mutually satisfying relationship".
Another term for it is "relationship addiction". People form and persist with relationships "that are one-sided, emotionally destructive and/or abusive".
Sitting in the atrium of Trump Tower on Tuesday, as Donald Trump harangued the press — well, you know where I'm going. For all the abuse, for all the belittlement, we as reporters show no sign of ending our relationship addiction with Donald Trump.
Much of our cravenness is easily explained. It stems from the record-breaking television ratings that Trump has generated and, just as important these days, millions of online hits.
A human headline, he more than satisfies the viral requirements of our new media age. At a time when media organisations are struggling still to monetise online news content, and to make the painful shift from print to digital, along comes the ultimate clickbait candidate, a layer of golden eggs.
Understandably, hard-pressed news executives are echoing the words reportedly uttered by Hillary Clinton's campaign manager, Robby Mook, at her Brooklyn headquarters: "I've got to get me some Trump."
It has meant that the default setting for cable news channels here is a split screen showing an empty Trump lectern on one side with pundits on the other, bloviating endlessly as they await the billionaire's arrival.
Entertainment value
As for a Trump news conference, it is rather like broadcasting one of those freeway police chases filmed from a helicopter: car crash television that you want to stay with until the end — though perhaps the more accurate analogy is of security camera footage that captures a street fighter who has no qualms about reaching for the broken bottle. It is unedifying, gruesome even, but also utterly compelling.
It explains why none of the news channels cut away from the Trump news conference yesterday, even as it degenerated into a one-way slanging match. Or why none of the reporters present, myself included, simply got up and walked out.
Yet the media's Trump relationship addiction is not explained by commercial imperatives alone.
Political reporters have a tendency of writing a campaign narrative that comports with the race they ideally want to cover. It's not an invented narrative, as such — we can't simply make up storylines. But I would suggest it's a slanted narrative, which, rather than betraying a liberal bias, reveals a "great story" bias.
In a reworking of the old newsroom adage "if it bleeds, it leads", candidates tend to be assessed on the basis of their journalistic entertainment value.
My sense, while covering the 2000 campaign for instance, was that reporters handicapped the race in favour of George W. Bush because the possibility of a son following his father into the White House, with all the oedipal complexity that went with it, was a better story than seeing Al Gore become president.
That would have felt like a Clinton third term, absent its charismatic leading man.
This tendency was even more pronounced in 2008, during the Democratic primary campaign, when journalists were more excited by the prospect of the first African-American president than the first female president, Hillary Clinton. Everyone wanted to compose their own first draft of that dramatic historical moment.
Trump is also a beneficiary of great story bias. Never before has there been a candidate with such journalistic entertainment value.
His unexpected emergence meant that we ditched our initial narrative of Campaign 2016, which we had set up a dynastic showdown between a Bush and a Clinton, in favour of a better storyline.
Willing enablers
The media didn't create Donald Trump, the basis of the ever more fashionable "Frankenstein's monster" critique of the press. But we have been more willing enablers than we would care to admit.
So while there has been no shortage of critical coverage of Donald Trump, there has been a reluctance to go for his jugular.
This tendency is most noticeable in broadcast interviews. Jake Tapper's interview with Donald Trump, in which the billionaire failed to disavow support from white supremacists and said he needed to do more research on the Ku Klux Klan before condemning it, offered a case in point.
Tapper, who has done some excellent interviews during this campaign, was tough and probing but did not go in for the kill. An obvious follow-up question would have been "do you really need to do more research on the KKK to condemn it" but he did not ask it.
As for the interview between Megyn Kelly and Donald Trump, it provides the textbook case study of campaign co-dependency.
Kelly rocked Trump in a televised debate last year, with a brilliant and legitimate line of questioning about his misogyny. But when she sat down with him at Trump Tower for a prime time special, and talked about his hate-Tweeting, she described how she imagined him doing it wearing "a crushed velvet smoking jacket, chaise lounge, slippers".
Mainstream media's weakness
Jon Sopel, my colleague and compatriot, wrote a terrific blog on the Trump press conference, observing: "The remarkable thing that has struck me as a British correspondent living in Washington, and who is used to a robust relationship between journalist and politician, is how Trump has been treated with kid gloves."
I could not agree more. The preference in American broadcast journalism is to end interviews on amicable terms. There is not the adversarial tradition of British interviewing, nor a US equivalent of John Humphrys or Jeremy Paxman.
What's also striking is that we as journalists do not have the power of old. Trump and other candidates have used Twitter especially, not only to bypass the media but also to become part of the new media themselves.
The billionaire's Twitter account has more followers — 8.5 million — than the Washington Post, ABC News, NBC News, the Huffington Post or Buzzfeed. He has become a self-publisher, and provided an unfiltered commentary of his own. Trump's strength is a measure of the mainstream media's weakness.
That imbalance was evident at the news conference in Trump Tower. He possessed the only microphone. He could drown out every reporter. He controlled who asked the questions, and probably half of the journalists present did not get the chance to do so.
Ever the shrewd media operator, he also knew that the cable news channels would stay with it until the end.
For another illustration of our comparative powerlessness, just witness the number of stories that have been written about Trump, which in an ordinary election cycle would have been disqualifying — his misogyny, his racism, his incitement of supporters to punch protesters in the face, his cussing, his refusal to release his tax returns, his constant flip-flopping on policy, Trump University, etc, etc.
Much has been written about how Trump defies the usual laws of political gravity, but one of the reasons is that modern-day media organisations lack orbital pull.
The Trump obsession has affected our coverage in subtler ways, too.
Had it not been for our fixation with the Republican contest, we would have paid more attention to Bernie Sanders' extraordinary success. Yet we've downplayed that storyline.
This is partly for valid analytical reasons. Early on, it became clear that Hillary Clinton was winning the all-important "black vote" — this race has proven again that it is all but impossible to win the Democratic nomination without it — and had the support of so many super-delegates that her lead became insurmountable.
But I wonder whether another explanation for short-changing Sanders goes to how Trump has impacted our professional pride. We can cope with being proven spectacularly wrong in one race, the Republican contest, but not two.
Absent Trump, journalists would have felt the Bern far more strongly, because it would have been the best storyline on offer. Again, it demonstrates how we as journalists tend to talk up certain narratives and talk down others, of how we are prone to great story bias.
Confessedly, I hated being at that Trump news conference, most of which I spent with my arm thrust skyward trying unsuccessfully to ask a question. But I also admit to being enthralled by the most extraordinary election campaign I have ever covered.
Like every other journalist, I dare say I'll be back the next time he summons us to Trump Tower. Perhaps, if he continues to be so personally abusive, journalists should stage a walkout. That said, I suspect we'll remain planted in our seats, sufferers of co-dependency, fellow Trump relationship addicts.