Sadly, in this world it is acceptable to dismiss people who are living in fear of demonic activity as "unstable", foolish, ignorant and superstitious. 

What these dubious "paranormal Experts" fail to realize when they dismiss those in question is that demons are not rare and exotic "chaos energies" that we hardly ever have the displeasure of encountering.  They are very real, have likes and dislikes, personalities and memories, and are not hampered by the laws of our universe that we as mortal humans have to live in. 

They are very commonplace and quite a daily element for billions.  people who are made to feel as if they are ignorant for believing they have a demonic infestation are also being victimized by the paranormal community that is supposed to exist to aid these very people.

I am acutely aware that droves of alleged victims are merely psychic vampires who are desperate needy people who will say anything to have groups of paranormal investigators or pastors dote over them.  I am not addressing those "people".  They are an entirely separate issue all together that is more pathological than paranormal. 

Rebecca

Here are some tell-tale signs that it is demonic:

{I must advise you that some of these symptoms may be side effects of medication or mental & physical illness. You must use discernment so as not to be "medieval" about these issues.}

• seeing black humanoids or black dogs
• ghost like entities with missing features {without  a face or eyes is common}
• growling noises that do not have a source in this realm
• being pinched, punched, or slapped when nothing is there
• have you been sexually assaulted or raped by something invisible
• are you held down or grabbed by something you cannot see
• nighttime paralysis when awake & lucid {often associated with a manifestation/visitation, not naturally occurring sleep paralysis that occurs when you awaken before your soul has completely merged with your sleeping body which is equally as bizarre or frightening and can also have sexual or fearful elements.}
• abrupt head pains or nausea that passes when sensing fear
• scratches on your body when no one is there
• anomalous voices such as preternaturally deep, very fast, or angry
• becoming abruptly ill without cause {i must add that I have physical symptoms when I am near a ghost or a demon. with time and experience you may learn to tell the difference.}
• voices that seem to come from deep inside walls shouting your name, fighting or having orgies
• a naturally sturdy person becoming weary or faint
• regular daily fatigue setting in when you were normally healthy
• beset by insomnia {this is also a symptom of demonic oppression. they break us down by keeping us awake for long periods to break our will.  We are much easier to influence after being kept awake for too long.}
• Are you often seized with unexplainable fear that makes you feel physically ill
• do you feel as if your organs [heart or lungs] are seized or made to palpitate by something that you sense to be evil  {this is odd for someone who does not have an ailment such as asthma or heart disease or hypertension}
• suddenly feeling hot spots or freezing areas may also be a manifestation of a demon
• items you use daily that you do not misplace disappearing, after losing your mind tearing apart your house for the fifth time are never found again
• popping sounds often accompany demonic activity {not house settling noises, more of an electrical type of sound}
• Knocking or booming noises may occur in the foundation or walls of a home.  They have a muffled fx filtered sound, they sound synthesized or fake somehow. {often misdiagnosed as a poltergeist, which is basically just a demon.}
• Are you a naturally cheerful person who is abruptly taken over by despair or rage {You consider yourself to be free of mental illness and have seen a psychiatrist}
• Have you experienced being swiftly taken over by an urge to kill yourself {and you are not suicidal or bi polar}
• Do your pets often growl or act fearful of something you cannot see {Animals see into spectrums of light or energy our eye's do not}
• Are you suddenly plagued by suspicion of trusted friends and family without real reasons {Once again you have not been diagnosed with any mania or schizophrenia}
• Are you suddenly experiencing aberrant thoughts {To be sexually savage or to rape & harm humans and animals}
• Are you receiving vivid impulses to cut or hurt yourself  {Doctors may diagnose this as a symptom of trauma but this is also a trait of demonic assault}
• sudden putrid smells of death or smells of sulfur {this isn't just something that happens on "Supernatural"}

Reality check: It is logical to say that there are millions of demons, probably more.  They are extremely territorial, and clever. Diabolical's [Fallen Angel's] have an incomprehensible intelligence, whilst demon's [disembodied souls of nephilim] being much baser creatures tend to be a bit insane. Keeping tabs on us, our weaknesses, and how to manipulate or mentally unravel us is not an obstacle for them.  Rather it's their favorite hobby and a passionate obsession.  It's their mission.

   Often in the realm of paranormal investigators, I have noticed that many people do not understand that demons are common and a regular element of life in this world. Their activity is much more mundane than people are willing to discern.  More people are dealing with them than they know, the sooner we all understand this the easier it will be to protect ourselves from their kind. 

And now common signs of human haunting's:

A note: Since demonic entities impersonate humans to keep us from understanding truly what happens in the higher dimensional plane of the spirit worlds, it is difficult to separate the two.  I'm not saying there is no such thing as a ghost, we just really don't know what they are, how they exist and what we are actually dealing with when experiencing this phenomena. You'll just have to pray and play it by ear.  With that in mind let's proceed

• Smelling perfume that no one is wearing
• Scent of tobacco or pipe smoke when no one has lit up
• Sounds of someone going about their daily routine that is no longer with us {I used to live in an old apartment that a lonely man had died in.  I often used to hear him walking down my long hallway late at night to use the bathroom.}
• Are your belongings moved after you put them where they ought to be as if someone else is saying "No! that goes here!" {This is also a tactic of demonic activity used to slowly unhinge your grasp on sanity.  "They" derive great pleasure from making perfectly normal people completely crazy, or "gaslighting" someone.}
• Remembering something that has not happened to you, or, having a memory projected into your mind, when in certain rooms or using pieces of furniture, or having a sense of past activities that may have occurred {if you are a sensitive you will know.  For the vulnerable this is a stratagem used by the demonic to influence someone to detach from the present and their life by getting lost in someone else's past.  In addition this is also how we are tricked into thinking reincarnation is real.  If you are offended by my saying "Oh I was day dreaming that I was Cleopatra or Napoleon so I must've been! That's proof of reincarnation!"  No, it's proof we are gullible and have an innate desire to be special & an imagination that is manipulated to our detriment, ergo we need all the help we can get.}
• Some sensitive's may also become influenced by the deceased. Displaying the dead persons traits or mannerisms {Once again be aware, this may also be a symptom of possession or multiple personality disorder. Pray to God that he give you the insight to see what is really going on and that you don't need to take the "victim" to a psychiatrist!}
• Cold spots on furniture or in rooms {Using discernment to tell whether or not this is human or non human.  The more experience you have with this phenomena the easier it will be over time for you to tell what it is.}