This question arose recently when myself and a student were building on the subject of potential unforeseen and adverse side effects that could conceivably result from the practice of magick as whole, and that which involves spirits traditionally regarded as "evil" in particular. Needless to say, as one of a few practicing magicians who isn't "afraid of the dark" the idea intrigues me. (and no, I don't mean the dark fluff bullshit so aggressively marketed these days as "the next big thing". Thats not dark. Nor is it of any value except to the social outcast seeking to be seen as rebellious; It's just cleverly marketed crap, much like the finbarr corpus).
What provoked the discussion was a recent encounter my student and I had in a well known, perhaps the most well known, occult bookstores in the US. Being the bibliphile I am, I am always on the look out for a title I've yet to read, that I can add to my collection, or that I can offer on eBay or my website. While browsing, my attention was called to the front desk where a man, quite scraggly an unshaven, clearly who had fallen on hard times, was offering to sell a dozen copies of the same book. Intrigued and in hopes of being next in line to purchase a copy if it was anything of interest to me, I approached. I noticed that oddly enough the man before me peddling his wears, clearly in need of a good meal and shower looked familiar, although I couldn't say from why; at least not until I saw the books he was trying to sell. To say that I was surprised to see that the man before me was in fact the books author, and one whom I hold, or held, in great esteem as one of my predecessors by whom I was greatly influenced would be a huge understatement. So great was my interest in his past work that while in prison I obtained his address and wrote him seeking to pick his brain and impose upon him for further insight into the work he has expounded in his books. Much to my surprise at the time, he took the time to respond and even sent me several dozen pages from a manuscript he was engaged in writing at the time as a follow up to the one he was now offering for sale. (Incidentally, of 4 authors I wrote while locked up, he was the ONLY one who responded) Out of respect for the gentleman, and in the interest of protecting his privacy, I won't identify him.
The man who had authored the books for which I respected him was highly educated, eloquent in speech, and extremely knowledgeable. The man before me clearly a shell of his former self. I engaged him in conversation, had a quick starbucks lunch with him and was almost saddened by the fact that the man who had written some of the best books on Goetic and Grimoiric work I had ever read was so clearly of severely diminished mental capacity - so much so as to make him almost incoherent. When conversing, he could hardly hold a thought for more than a moment. Would zone out completely, staring into space, and upon returning his focus to me, be fully engaged in a conversation completely different from that which we had been holding prior to his segue. At one point I asked about a particular experiment he had written of involving Belial. For a moment he seemed to comprehend and willing to discuss; however the extent of that discussion was "Yeah, Belial. Man that was... That... Belial, man. When we called Belial we had to, we had to..." Seeing that he was again about to zone out, I tried to refocus his attention, asking him "Was it a success? How did it turn out?". While there is very little in life that can render me speechless, his response, given in a quieted tone and with a dead expression on his face, was "I'll let you know how it went if it ever ends" followed by a period of silence after which he continued, "Man have you read that 50 shades of gray? Thats some.. thats some crazy...".
On returning to the bookstore to finish my perusal of the shelves, I had the chance to speak with the proprietor who shared the fact that the man was actually a customer of his and something of a friend of the family. After assuring me the man had suffered no mental illness, stroke, or otherwise debilitating conditions, I, in my usual politically correct way, asked, "Ok then so just what the fuck? How did John Doe become the guy who just left?" The answer I got was simply, "I wish I knew. He and his friends were planning an evocation from Lemeg, they even came in and did a lecture about it beforehand. The next time I saw him he was fucked in the head." He went on to explain that the man could hold a mundane conversation fairly well, but any time the topic of conversation turned to anything relating to Magick, it was like "His mind just checked out for the day. He was just gone.".
This experience, unsettling as it was, led to a discussion between my student and I about the various schools of thought that swear that practice of Magick of our sort, the sort our friend the author mentioned above was quite well known for, can result in mental imbalance and do serious psychological damage to those who undertake it unprepared, or who do so without being well practiced, learned, and in a state of mental and emotional fitness nearing perfection. Old stories of those who had dared undertake this work going mad and requiring institutionalization came to mind, along with the numerous dire warnings found in the classical Grimoires. Was his work with Lemeg the cause of his clear mental incapacity? But no, it couldn't be. He was not a newbie picking up a paperback Goetia and jumping in with both feet, he was WELL known, and considered by everyone with whom I've spoken as the real deal. A mutual friend who participated in a ceremonial evocation with him in the late 90's swears even now that what he saw this man do that day was beyond anything he had heard of before or since. So clearly he was not the unprepared novice scared out of his wits by any evocation of which I can conceive.
So the question my friends is this. Did Goetia scare the wits out of our friend the author, literally? Are Magicians who dabble with "darkness" more inclined to mental or emotion affliction? Personally I don't believe so, unless they have underlying and unresolved issues prior to undertaking the work; but that could also be said of any sort of Magick, could it not? Those with a weak constitution undertaking to stretch, bend and at time utterly shatter the fabric of reality through Magick, whilst also, if any measure of success is achieved, shattering any lingering belief or faith in the tenets of their religious roots that say such things are not possible, are surely more likely to encounter such emotional turmoil. Gods forbid a dabbler, a gothic wanna be rebel attempting an evocation as part of his social rebellion were to achieve any level of success or spiritual contact, I'm quite certain he'd flip his goddamn lid faster than the grill boy at Mickey D's flips burgers. Myself, having prepared and practiced for years upon years, upon achieving TRUE success in evocation for the first time and having the full presence of a spirit before me, and all the practice in the world couldn't have prepared me for the shell shock. But, despite that, and despite having devoted much of my life subsequently to this practice and to evocation of "demons" much higher up the food chain in the (man made) hierarchy, I'm still pretty damned normal, I'd say. Or at least as normal as I've ever been.