Centuries ago, the seeming cure for insanity was to cut a hole in the skull to let the evil spirits escape. Not too long after that, men who called themselves doctors discovered that by scrambling the prefrontal cortex, with a metal implement, inserted through the ocular cavity. Barbarous. With this new treatment, a simple metal clip, implanted into the brain of the patient, and like that, their insanity is almost completely cured. Therapy and medication, and even the most deviant twisted psychopath can be rehabilitated with relative ease.
Procedure: Nerve Stapling is a rather simple procedure. A small metal clip, or staple, in inserted into the amygdala of the human brain, typically through a sinus tap. This disrupts the function of the amygdala which in turn functionally neuters the patient's emotional capacity. A person who has experienced nerve stapling will have either no, or a strongly decreased ability to feel emotions, or emotional values.
They call it being gentled, or stilled, neutered or brain-spayed. They poke around inside your head, and when you come out of the clinic, you are a different person. They show you the success cases, but they never follow up. You know why? They don't follow up because they leave. My mother was stapled after a violent outburst. She came home, and stayed for six months. She didn't look at us the same after that. We weren't her children anymore, she didn't love us because love is a fucking emotion. Dad regretted it, because they sprang away from each other. In a week we were living in a 1950s sitcom, fake smiles, and parents sleeping in different beds, in different rooms. Eventually she got tired of pretending to care about us, and she left. She wasn't sorry, she wasn't glad either, she just wanted to get away from us.
Why?: The most common reason for administering nerve stapling is to counter the sanity eroding effects of arcanotechnology, and as a corrective action for people who have become emotionally unstable due to exposure to a dimensional fatigue event. Once the basic ability to feel fear, anxiety, or pleasure is removed, most of the motivations for erratic and uncontrollable behavior are remedied.
Short Term Effects:
Cessation of behavioral addictions (rather than chemical addictions)
Emotional Neutering (reduced ability or inability to feel or express strong emotion)
Increased rational behavior.
After being stapled, the most immediate effects are the dramatic loss of emotional outbursts and reactionary behavior. After that almost all addictions slough off. Lacking a chemical reward for indulging in addictive behavior, the impulse behind it fades. This does apply to intimate relationships, and the nerve stapled become asexual in their interests (or lack thereof) or continue to go through the motions of intercourse, devoid of intimacy or pleasure.
It is relatively common for criminals who aren't quite dangerous enough to be executed, but too dangerous to exile and turn loose, to be stapled. This turns them into social outcasts and they are no longer able or interesting in returning to their criminal lifestyles. Likewise, clones are frequently stapled, especially military clones, so that they are unperturbed by suicidal missions and keep following orders regardless of what sort of shit monster or dimensional horror show they are experiencing. Some veterans and extreme crime/violence victims undergo nerve stapling to escape the effects of PTSD and other psychological trauma.
Long Term Effects:
Depression (feelings of emptiness or hollowness)
Social Isolation (inability to form relationships)
Learned Introversion (preference for solitary activities)
It is generally consensus that nerve stapling is a bad thing. Bereft of pleasure and pain, the stapled are withdrawn, melancholic, emotionless, and endlessly stoic. It doesn't help that in many countries, the technology is used as a form of population control, and political dissidents will be apprehended and stapled, and then turned loose. It becomes incredibly demoralizing to see a passionate and charismatic leader overnight turn into a ghost of themselves.
Nerve Stapling and Society
The practice of Nerve Stapling was pioneered on the critically insane and hardened criminals. The technique was highly effective, and even the most rebellious and hostile individual was rendered compliant and nearly mute by the procedure. The violently insane were stapled and re-evaluated, and showed dramatic improvement on their personal condition. Being emotionally dead in some cases was preferable to the manifestations of their insanity. Likewise, deeply ingrained sociopaths and other criminals saw major personality shifts after the procedure.
They Called Her Annika
Annika was an up and coming mecha pilot, and demonstrated exceptional skill controlling the large machines. She was involved in a Class 4 Dimensional Fatigue event and had a close encounter with a potential exo-teratomorph with massive psychotronic attack power. Rendered violently insane by the encounter, Annika spent two years in a state asylum where they attempted to treat her psychoses. She was eventually nerve stapled, quelling the violent and psychotic impulses she had.
A month later Annika returned to active service with an Iron Hand squadron. These squadrons consist of expendable pilots and second line machines, they are intended to go into fights near and inside dimensional fatigue events, hunting out the biggest horrors and bringing them down first. These units have high mortality rates and frequent psychotic burn outs and suicides. Unperturbed by the fear of death, and unmoved by the unimaginable horrors in front of her, Annika proved a staggeringly dangerous opponent, and finished an unprecedented six tours in Iron Hands ops. She was only retired when after her 39th sortie, her mecha was destroyed and she was almost killed. After a brief hospital stay, she returned to the site of her near death and committed suicide.
Unfortunately, this was in the middle of a celebration event, and well over a quarter million people watched a Federation mecha ace blow the back of her skull out with a service pistol.
There is a trope anime character, the emotionally dead girl, most notable being Rei Ayanami from Neon Genesis Evangelion. Rei was Nerve Stapled, so she has no screaming Shinji fits, she does what she is told, barely demonstrates any emotion, has no romantic interests, and what emotions she does have, they are personally suppressed and she doesn't relate well to others. In the Cosmic Era, if you are too rambunctious, too rebellious, too insane, to psychotic, and they don't want to spend the money to give you a robo-lobotomy, they will Nerve staple you, and then you simply won't care, and won't be able to emote or relate to others. This isolation extends to other nerve staple recipients. They cannot relate to others any more than they can relate to normals.
When Annika's diary and personal notes were found, it caused an uproar. The ace pilot had pages and pages of drawings and notes related to emotions and facial expressions, how to recognize them on other people and how to emulate them herself. There was no passion, no feeling, behind the art, but the attempt was considered one of the most human things of that decade.