context: Nothing throws you for a loop like when you swear you can hear something that doesn't seem to have an explanation. If what you heard really doesn't have a source, it might be an âauditory hallucination.â It can range from a simple sound to hearing music so clearly, it's hard to believe there's no band or radio nearby. Often, what people hear is voices. Sometimes, they're mean, critical voices. But others might be neutral or even pleasant. No matter what the sound is, it's a clear sign to go talk to your doctor. The sooner you do, the quicker you can find out what's going on and get treated. Mental illness is one of the more common causes of auditory hallucinations, but there are a lot of other reasons, including: Alcohol. Heavy drinking can cause you to see things that aren't there. You might hear things, too, both as you drink or when you quit after you've been drinking for many years. Alzheimer's disease and other types of dementia. You're more likely to hear things in the later stages of Alzheimer's. A similar condition called Lewy body dementia can cause it, too. ( But it's more common to see things -- visual hallucinations -- than hear them with this type of dementia.) For some people, the voices seem so real, they talk back to them. Brain tumors. Hearing things doesn't mean you have a brain tumor. But it could happen when a tumor is in the part of the brain that deals with hearing. You might hear anything from random sounds to actual voices. Drugs. Certain street drugs, like ecstasy and LSD, can make you see and hear things that aren't there. It can happen while you're using them or when you quit after using them for a long time. Epilepsy. When seizures from epilepsy affect the brain area that processes hearing, you might hear a buzzing sound or voices. In some cases, it warps how you hear things, so they're not as loud or clear. Hearing loss. People with hearing loss in one or both ears may hear anything from odd sounds to music and voices, none of which are really there. High fevers and infections. Some infections, like encephalitis and meningitis, can make you hear things, along with the other symptoms. The same is true for high fevers. Intense stress. Serious stress, as you might have after going through something traumatic, can cause hallucinations. It's especially common to hear the voice of a loved one after their recent death. Mental illness. Hearing voices is very common with schizophrenia. The voices may seem to come from inside your head or outside, like from the TV. And they could argue with you, tell you what to do, or just describe what's happening. It can sometimes happen with other mental illnesses as well, including: Bipolar disorder Borderline personality disorder Major depressive disorder Posttraumatic stress disorder ( PTSD) Schizoaffective disorder Migraines. Often, if you get migraines with auras, you see things. But some people hear things instead. Usually, it's voices. And that may be more likely if you also have depression. Parkinson's disease. It's more likely that you would see things that aren't there when you have Parkinson's. But in some cases, you hear things from the scenes you're seeing. Side effects from medicine. If you begin to hear things once you start a new medicine or your doctor puts you on a higher dose of something you already take, that change could be the reason. It most often affects older adults and gets more likely the more medicines you take. Sleep issues. It's pretty common to hear a sound just as you fall asleep or wake up. And it's usually not something to see your doctor about. But if you fall asleep randomly (narcolepsy) or have a hard time falling asleep (insomnia), it's much more likely to happen. Thyroid disease. Myxedema is a rare condition where your thyroid is not making enough hormone and your levels get dangerously low. It's a life-threatening condition that can also make you hear things. Tinnitus. Doctors don't think of the usual ringing or hissing of tinnitus as a hallucination. But this condition can raise your risk. It may be more likely if you also have depression. Your doctor will start with your health history and symptoms. You may answer questions like: What are you hearing? Voices? Buzzing? Other sounds? When did it start? Does it tend to happen at certain times, like as you're falling asleep? Do you have any other symptoms when it happens? If it's voices, are they threatening, rude, pleasant, or normal? What medicines are you taking? Are you using any other drugs? After that, you'll get some tests based on what your doctor thinks might be the cause. For example, your doctor might suggest you see a psychiatrist to check for a mental illness. You could have some tests based on what your doctor thinks might be the cause: Electroencephalogram ( EEG): This measures electrical signals in your brain, to look for epilepsy. Hearing exam: This checks for hearing loss or tinnitus. The goal is to help your doctor narrow down what might be happening. This depends on what's causing you to hear things. Sometimes, once you and your doctor solve that problem, the hallucinations go away, or at least may not happen as much. In some cases, there's an easy solution. Your doctor may lower the dose of a medicine you take. In others, treatment is more complex, and you may need to try several things to see what works. For example, with an illness like schizophrenia, you might need a mix of medications, therapy, and other care.