What Is Polydipsia?

Medically Reviewed by Zilpah Sheikh, MD on November 23, 2023
Written by Terri D'Arrigo
6 min read

Polydipsia is the medical term for excessive thirst or compulsive water drinking.

Drinking plenty of water usually takes care of your thirst. But sometimes, no amount of water or other fluid seems like enough. You'll drink and drink and drink -- and drink -- and still be thirsty. That's polydipsia.

Treatment for it depends on why you have it.

Primary polydipsia

This means you have an excessive thirst but there's no physical reason for you to have it. Primary polydipsia is subdivided into psychogenic polydipsia and dipsogenic polydipsia.

Psychogenic polydipsia is very common among people with schizophrenia and other mental health issues. Doctors think these patients might have a lower sensitivity to the signal in the brain that indicates thirst, or else they might use this as a way to purge or self-treat.

Dipsogenic polydipsia refers to drinking excessive amounts of water or other fluids, either due to a malfunction in the hypothalamus (the part of the brain involved in thirst), or under the belief that this is part of a healthy lifestyle.

Secondarypolydipsia

This means there's a physical reason for your excessive thirst. It's usually due to a medical condition such as diabetes, or a medication such as a diuretic (“water pill”) taken to lower blood pressure. Secondarypolydipsia is much more common than primary polydipsia.

Polydipsia is typically a sign of another illness, but it has symptoms of its own:

  • Persistent dry mouth
  • Excessive peeing (polyuria)

People who have polydipsia spend a lot of time in the bathroom. Instead of the 3 quarts that most adults pee out in a day, they can pee out as much as 16 quarts, depending on how much fluid they drink and what's causing their polydipsia.

If your polydipsia is caused by another condition, you'll likely also have symptoms of that condition. For instance, if you have diabetes, in addition to feeling very thirsty and peeing a lot, you may:

  • Lose weight
  • Feel very hungry
  • Have numbness or tingling in your hands or feet
  • Have blurry vision
  • Feel very tired
  • Have more infections or sores than usual

You usually get polydipsia as a symptom of other conditions, such as:

Diabetes: Super high blood sugar will make you pee a lot. The more you pee, the more dehydrated and thirstier you get, and the more you drink. This condition is also called diabetes mellitus to distinguish it from diabetes insipidus.

Diabetes insipidus: What most people think of when they hear “diabetes” has to do with your pancreas. However, diabetes insipidus happens when there's a problem with your kidneys or your pituitary gland, which makes a hormone that helps control how much water your kidneys keep in your body.

Diabetic ketoacidosis (DKA): If you have diabetes, and your body doesn't have enough insulin to make glucose, it might begin to burn fat, which produces ketones. Ketones are the chemicals made by your body when it burns fat for energy. Having a lot of ketones in your blood makes it more acidic and can poison your body. Signs of DKA include extreme thirst and frequent peeing.

Psychogenic polydipsia: Due to a mental disorder, some people have an uncontrollable urge to drink water, so they drink it all day even though they don't need to. Mental illnesses that cause polydipsia include:

Brain injuries and damage: This could be from diseases such as HIV or other illnesses.

Dehydration: Loss of fluids (vomiting and diarrhea) from illness or excessive sweating and/or not drinking enough water can lead to polydipsia.

Alcoholism: Drinking excessive amounts of alcohol or beer can cause you to pee a lot, thus making you thirsty.

Certain medical conditions such as Addison's disease, kidney failure, and sickle cell anemia can cause extreme thirst.

 

Drinking too much water or other fluids can upset the chemical balance in your body and cause certain medical problems.

Hyponatremia

This is when you have too little sodium in your blood. Normally you get rid of extra water by peeing, but when your body can't keep up, your blood gets diluted. Sodium is an electrolyte, which is a mineral with a positive or negative charge when dissolved in water. Sodium helps regulate your blood pressure, plus the amount of water in and around your cells. When the concentration of sodium is too diluted, you get symptoms such as:

This condition can damage your organs and bones. As hyponatremia gets worse, you could go into a coma or die. In one case, a woman drank 30-40 glasses of water in a night, fell asleep, and died.

If you've been extremely thirsty for a few days and peeing a lot, and you have any of these other symptoms, call your doctor right away.

Water intoxication

This happens when you've drunk so much water that your sodium concentration falls below 135 milliequivalents per liter (mEq/L). The normal level is between 135 and 145 milliequivalents per liter (mEq/L). Water intoxication leads to hyponatremia.

Water intoxication is quite rare but can result from:

  • Drinking water after strenuous exercise but not compensating for electrolyte loss with a sports drink
  • Psychogenic polydipsia
  • Water torture (such as in prison or a fraternity drinking game)
  • Severe vomiting or diarrhea, which causes your body to lose sodium and increases your level of antidiuretic hormone secretion, so your body retains water instead of peeing it out

Certain diseases can affect your kidneys or liver and cause fluids to stay in your body (rather than going out). This will dilute the sodium level in your body.

Your doctor will order blood and urine tests to find out the sodium concentration in your blood and check for the presence of glucose in your urine, which is a sign of diabetes mellitus. Your doctor might also ask to measure how much fluid you're taking in a day by having you drink all your fluids from a specially marked container and also having you collect all the urine you pass in a 24-hour period in another container.

People with diabetes mellitus will have to adjust their care routine to try to manage their blood sugar better.

Your doctor might prescribe medication or hormones for diabetes insipidus. Or they might prescribe a change to your medication if that is the reason for your polydipsia.

For psychogenic polydipsia, treatment includes:

We all get thirsty after working out or eating salty snacks. But if your thirst doesn't go away even after several drinks of water, you might have polydipsia. Sometimes it is a sign of diabetes. Other times, it is a sign of mental illness. Once your doctor has decided what the underlying cause is, you can get treated successfully.

What is polydipsia a symptom of?

It can be a symptom of a physical disease (such as diabetes), a mental disorder (such as schizophrenia), or a side effect from a medication. Your doctor will run tests to see what the reason is.

How much water a day would be considered polydipsia?

If you're drinking more than 6 quarts or liters of water a day, you may have polydipsia.