"Psychically" vs. "psychologically" vs. "mentally"

This one has been giving me headaches for about a year now.

Some time ago, I created an AskReddit thread with the following title:

How do you psychically prepare for pain before a surgical procedure?

I was mocked in the comments. Redditors were saying that psychically refers to psychics (people who supposedly contact the dead). However, when I looked it up at The Wiktionary, the entry for psychically states:

1. in a psychical or psychic manner
2. mentally

I was also told that the proper word I was looking for is psychologically.

A few months later, in another thread, in one of my comments I wrote:

To perform a proper backflip, you have to prepare not only physically, but also psychologically.

And again, of course, I was mocked, because now, it turns out, I was supposed to use mentally, contrary to what I had been recommended before.

Could the native American and British English speakers of ELU tell me:

• Was I ever wrong in whatever I wrote to Reddit, or are Redditors wrong?
• Is there any difference between the three words in question?
• If there is any difference, how do I properly decide which/when to use?

Solution 1:

Psychological often refers to one's emotive and mental acuity state. Some people are psychologically better equipped than others when faced with hardship and particularly traumatic events in their lives, their minds will remain "sane" while others will suffer nervous breakdowns, fall into depression, or in more extreme cases, actually "lose their minds".

Mentally as an adverb, does not usually refer to one's sanity; to prepare oneself mentally before an arduous task is similar to psyching yourself up.

psyching yourself up: to try to make yourself feel confident and ready to do something difficult: I have to spend a little time on my own before I give a speech, psyching myself up.
C.D.O

mentally: connected with or related to the mind:
It's going to be a tough competition but I'm mentally prepared for it.
C.D.O

here the given example means to control one's nerves, anxiety, and emotional state. You mentally challenge yourself to face the task ahead. For some that task might even be traumatic e.g., speaking in front of a large audience, but it is a short-lived one, and people are rarely affected psychologically.

Psychically this one is trickier. First of all, as an adverb, it's not commonly heard in speech. Off the top of my head I can't think of an idiomatic expression which uses this term whereas its adjectival form, psychic, usually refers to a medium or any person "gifted" with paranormal abilities.

psychic adj : having a special mental ability, for example so that you are able to know what will happen in the future or know what people are thinking: psychic powers

psychic n: a person who has a special mental ability, for example being able to know what will happen in the future or what people are thinking: a gifted psychic
C.D.O

However, I believe, doctors and psychiatrists use the term psychic problems when referring to patients whose mental health is impaired or as many would say, are mentally ill. Why did I prefer the adjective mentally in that expression? I could easily have said psychologically ill and be understood, but it's a question of collocation. "Mentally ill" is by far the more popular term as the Google Ngram below confirms

Collocation

In Google books; "physically and mentally" yields a massive 10,200,000 results while "physically and psychologically" yields 1,340,000 results. If we add the term "prepare" the expression "physically and psychologically prepare" yields a modest 131 results whereas "physically and mentally prepare" produces a very respectable 1,510 results.

Summary

• How do you psychically prepare for pain before a surgical procedure?

Redditors were correct in saying that the term, psychologically prepared, used in that context is more idiomatic. Pain itself is not a task, a job, or a competition. To bear pain, especially prolonged pain, requires a healthy and rational mind.

• To perform a proper backflip, you have to prepare not only physically, but also psychologically

I wouldn't consider the term psychologically in this instance to be an error in the strictest sense of the word. It's fully understandable and I'm sure many native speakers have uttered similar things in their lives, nevertheless it's hard to argue against the term, mentally, being preferable. I would posit that performing backflips does not necessarily require a healthy, sane mind. It is a physical activity which requires a level of concentration and self-confidence.
^{(see: psych yourself up)}

Further data

Google books reports 9,960 results for "psychic problems"; 165,000 results for "mental problems" and 626,000 results for "psychological problems". By looking at their usage, the differences between these terms will be clearer.

EDIT

'Psychically' is better than 'mentally' in your first example, because it is that subconscious layer of the mind that one is addressing. Jon Jay Obermark

Whilst I may agree that the term, psychically, is not wholly inappropriate, psychically prepare is not idiomatic nor common. Indeed the Google Ngram chart shows that the expression psychically prepare is non-existent in American literature, whereas the expressions psychologically prepare and mentally prepare are both recorded.

The Chambers Dictionary 12th edition under psychic informs:

psy'chic adj. (also psy'chical) relating to the psyche, soul or mind; spiritual, spiritualistic; beyond, or apparently beyond, the physical; sensitive to, in touch with, or apparently having powers or capabilities derived from, something that has not yet been explained physically, eg apparently prescient or telepathic (psychical research investigation phenomena apparently implying a connection with another world; [...] ) psy'chically adv.

Solution 2:

I will not give you grammatical or etymologic explanations. I'm not a native english speaker either.

But as someone that's being studying ESL for more than 3 decades I cal tell you:

• Forget psychically. Almost nobody uses that word and when they do, they are talking about paranormal things.
• Use psychologically only in situations when a psychologist is helping someone, like in "the soccer team have been helped psychologically to improve their communication problem".
• You could have gone safely with mentally in both cases you mentioned.

Stick to what is common or sounds natural in english, not what is common or sounds natural in your mother tongue.

Solution 3:

You are just fine, and the commentators are excessively fussy.

'Psychically' has a long history borrowed from psychoanalysis of referring not just to the supernatural but to the deeper reaches of mental processing. 'Psychically' is better than 'mentally' in your first example, because it is that subconscious layer of the mind that one is addressing. Unfortunately 'psychically' had an earlier more widespread history related to the Spiritualist religious movement and its relatives. So it leaves a bad taste for many. They are simply not as scientifically cultured, or are more deeply steeped in the older cultural influences. Either way, the users of 'psychically' meant what you mean, mentally, but possibly at a level below ordinary consciousness.

'Psychologically' can mean exactly the same thing, but it is sometimes colored with an assumption of objectivity and conscious analysis. So the objector may have disliked that it was not subjective enough. It feels wrong to some speakers in situations exactly like yours, where the emphasis is on actions that feel extra-conscious. (Whatever preparations you make mentally for surgery or for athletic performance can't be too focused on conscious processing, because you are expecting them to affect something during which you are actually unconscious, or something quick enough that you do it entirely in 'flow'.) To those readers 'psychological' preparation would be based on a theory of the mind, and not on a feeling.

'Mentally' is neutral, and a good choice for not offending people who do not believe there is much structure or complexity to the way a person relates to the mind, or who have strong biases about how it actually works. It simply has neither of the other overtones unless it somehow contrasted with 'spiritually'. But I feel, in those two examples, that you want one of the implications it avoids.

You could go for the full risk and use 'spiritually' or 'subconsciously' asserting a little of how you feel the mind responds to us. It might be audacious enough to put off nigglers. People who do not share your bias will see it and correct for it, rather that assuming this is a vocabulary issue.

Solution 4:

It's true that psychically means "mental" or pertaining to the mind. Technically you can use the word the way you did. Take for instance the phrase:

The soldier was wounded both physically and psychically.

This is correct, grammar-wise. However, you won't hear this word outside of the field of psychology and you're increasing your probability of getting slapped in the face by a... psycho.

Let's look at a little background on the word. I used the word psycho just now, you used the word psychically, what's with the psy- prefix? If I had to take the wildest guess, I'd say it's some South Korean pop singer who perhaps got over 2 billion views on a YouTube video of an auto-tuned song that nobody understands in which he embarrasses himself and dances like a horse or something along that line. But that would be totally nonsensical, and I have no idea how I came up with such a ridiculous conjecture.

The psy- prefix is used in Greek for words that relate to the mind. The word psychically actually comes from the word psyche, which comes from a Greek word that literally means "breath." From breath came the word soul (anything that breathes has a soul), and from soul came the idea of the mind/spirit. With this in mind, the definition of the word psyche was formulated to be:

The human soul, spirit, or mind.

Of course, the word psychical therefore has the definition of relating to psyche as you have seen in the dictionary.

Wow, I'm proving you right! Right? Not really. Sorry to burst your bubbles but let me rejoice: Har har, har har. I burst bubbles professionally now; har, har. Now that I had my laugh, it's time to travel in time... to December 8th, 1871, in England. Professor William Crookes publishes a piece called the "Psychic Force", which describes his encounter of someone we would call today a psychic. The only useful text from his writing is the last paragraph (reproduced below), but you can read more on his Wikipedia page.

"Respecting the cause of the phenomena, the nature of the force to which to avoid periphrasis, I have ventured to give the name of Psychic, and the correlation existing between that and the other forces of nature, it would be wrong to hazard the most vague hypothesis. Indeed, in enquiries connected so intimately with rare physiological and psychological conditions, it is the duty of the enquirer to abstain altogether from framing theories until he has accumulated a sufficient number of facts to form a substantial basis upon which' to reason. In the presence of strange phenomena as yet unexplored and unexplained, following each other in such rapid succession, I confess it is difficult to avoid clothing their record in language of a sensational character. But to be successful an enquiry of this kind must be undertaken by the philosopher without prejudice and without sentiment. Romantic and superstitious ideas should be entirely banished and the steps of his investigation should be guided by intellect as cold and passionless as the instruments he uses. Having once satisfied himself that he is on the track of a new truth, that single object should animate him to pursue it, without regarding whether the facts which occur before his eyes are 'naturally possible or impossible.'"

I found an earlier (?!) piece that labeled criticism of many scientists regarding the "psychic force," but makes sure to note...:

Of course that is possible, and if true, would dispose of the "new force" ;— but if it happened so, Dr Huggins and Mr Crookes cannot be even decently good and acute observers, which their scientific reputation warrants us in believing them to be.

...that Mr. Crookes is a very reputable scientist.

From the Wikipedia page, we know that he probably regretted publishing this because it was all a fraud:

In a series of experiments in London at the house of Crookes in February 1875, the medium Anna Eva Fay managed to fool Crookes into believing she had genuine psychic powers. Fay later confessed to her fraud and revealed the tricks she had used.

But that didn't stop the people from freaking out. From then on, people started believing in the "psychics" the professor described, and movies, books, and other things started featuring those abnormal human beings who have supernatural mental powers.

Jumping back to the 21st century, in, uh, Allentown(??), if you go and ask people what psychic means, they'll tell you it refers to someone who can read minds, talk to spirits/the dead, etc. This is because, thanks to our culture, the word evolved to become a noun from an adjective that has been used since 1642 to mean "relating to the mind" with Crookes' definition of a psychic. So your 'pals' at reddit know the noun 'psychic', and thought (wrongfully) that psychically means relating to the noun. The word psychically is only related to the adjective psychic (which means "relating to the mind") and has not evolved to accommodate for the noun we added about 229 years later.

Psychologically can also mean the same thing and you're still grammatically correct. However, psychologically is usually never used because it's pretty ambiguous when you want to just refer to the mind. You'll only see it when people refer to the field of psychology, for instance:

Psychologically speaking, smart people are smarter than dumb people. -Confucius (jk).

The word psychological, on the other hand, is used commonly, as in the statement below:

Son: Mommy! I think I have AIDS.

Mom: It's just psychological. You're too ugly to find a mate to contract AIDS from so don't worry about it, noob.

But that's because "mental" doesn't fit and "mentallic" isn't a real word.

So psychologically - out, mentally wins and makes the statement sound the best.

The verdict (tl;dr)

• Redditors speak before they think.
• Your usage is correct according to the words' definitions.
• In the defense of redditors, what you said would sound weird to any native English speaker.
• "Mentally" is the best word to use in your question because it's specific and, really, just flows. How do I mentally prepare.
• To know which one to use for next time, it's one of those things that really just take practice to master (as you hear different phrases use different words).
• I spent too much time on this answer and I should stay away from this website.