Every academic discipline has a concept or two that its scholars disagree upon. In the social sciences, these can even be the fundamentals of the subject, and, sadly, they aren’t always so much disagreements of definition as concepts the experts don’t grasp. In Economics [the discipline I was educated in], there is a famous war over whether economists understand “opportunity cost” — a concept that is raised not only in undergraduate texts but even in high school classes.
That said, Psychology appears to take the cake for being the most internally confused academic discipline. Ever. I first became aware of this problem with respect to a subject I have great personal experience with (by virtue of being firmly lodged in said category), and that’s introversion.
Recently, this psycho-confusion has come up again as I’ve been reading two books that have major discussions around psychological definitions. One is Dean Haycock’s Murderous Minds, which devotes a whole chapter to the fight over how psychopathy is defined and differentiated from other conditions (in part, because another term — Sociopath — exists to spur confusion, but even without that term [which some psychologists think of as a synonym and others think of existing in another ballpark] there would be a huge gulf in expert opinion.)
The second book is Julia Shaw’s The Memory Illusion, which is a fascinating and generally thought-provoking book. In it, Shaw claims that hypnotism doesn’t exist. I found this difficult to believe (both because I’ve been in a hypnotic trance state and because there is a well-established literature on the subject [i.e. it’s not like parapsychology concepts, e.g. clairvoyance, which are highly controversial]) until I realized that Shaw’s definition of hypnosis was filled with all the misconceptions that one would expect of an individual entirely unfamiliar with a hypnotic trance — except maybe having seen a stage hypnotist once or twice.
5.) Introversion: Introverts are often confused with those who have social anxiety disorder(severe shyness) — which an introvert may or may not have, but which an extrovert also may or may not have. (While it’s probably true that introverts experience social anxiety disorder at a higher rate than extroverts, there is a big problem with equating the two — not the least of which is that one can beat one’s social anxiety and still be an introvert.) It should be pointed out that Susan Cain’s excellent book Quiet (among others) has done a lot to bring a consensus view to the subject, but one still hears people — even experts — equating shyness and introversion.
4.) Psychopathy: Like many confused topics (including introversion and hypnosis), part of the problem is that everybody has a mental construct of what psychopathy is before they learn anything formally about it, and sometimes those preconceptions survive the presentation of formal knowledge — even, apparently, for the experts. Maybe a person has read American Psycho or maybe they’ve seen Dexter or the movie Psycho, and so they know very well that a psychopath is a murderous maniac, and, therefore, they may not swallow the information that most psychopaths function just fine in society and aren’t even considered inherently mentally ill.
3.) Schizophrenia (v Split Personality): This is probably one of the most discussed of the confusions in the field. To be fair, this may be largely ironed out these days, but it certainly took long enough. Multiple Personality Disorder (commonly called Split Personality but today called Dissociated Identity Disorder [DID]) is usually a trauma-based disorder that results in schisming of personhood. Whereas, Schizophrenia is a genetically transmitted disorder that involves a disconnect with reality, but not necessarily a separation of personalities.
2.) Hypnosis: I mentioned Julia Shaw’s statement that hypnosis doesn’t exist. In her book, she mentions several preconceptions about hypnosis that are quite different from my limited (but existent) experience with hypnosis. To be fair, many hypnotists would tell you that the term hypnosis (coined by Scottish surgeon James Braid) is a confusing choice because “hypno” suggests the state is like sleep — which, not so much. First, Shaw calls the hypnotic trance state a non-attentive state. (This comes up because she is making the point that attention is critical to memory formation, which is probably entirely true and I don’t have any dog in the fight of whether hypnosis can help memory.) What I am arguing is that hypnosis is not a non-attentive state. It’s a highly relaxed state, but might be more accurately called a hyper-attentive state. Maybe the confusion is because stage hypnotists frequently successfully suggest participants temporarily forget things in deep trance, but keeping one’s attention focused (on what may vary, though it’s usually voice) is critical to the hypnotic trance state. Second, she suggests that hypnosis is an act that must hinge on the activities of the hypnotist — i.e. the hypnotist as sine qua non. I think many, if not all, hypnotists would admit (often begrudgingly) that the hypnotist is the most dispensable element of the process — or, as it’s more commonly phrased, “all hypnosis is self-hypnosis.” Third, she seems to have problem with hypnosis being considered an altered state of consciousness. To my mind, everything but ordinary waking consciousness is an altered state of consciousness. I don’t know of any way in which a hypnotic trance state could be confused with ordinary waking consciousness. (If you’re sure of it, go to a dentist who uses hypnotism for pain reduction and have them yank your tooth in a state of ordinary waking consciousness, and then compare your experience to the individuals who had it done under hypnosis. See here for a related BBC special on the Science of Hypnosis.)
1.) Delirium (v. Dementia): To be fair, by the time an individual is in a full-blown state of either, these conditions are nearly impossible to distinguish and have overlap. However, delirium has quick onset, involves severely impaired attention, and can fluctuate greatly from one day to the next. On the other hand, dementia often progresses slowly, begins with mild impairment of attention and focus, and is a far more consistent state.