Polydipsia is the medical term used to describe excessive thirst, which leads to an abnormal urge to drink large amounts of water per day. It is associated with symptoms such as increased urination, dry mouth and dizziness.

Polydipsia can be caused by diabetes mellitus or insipidus, mental disorders, changes in the hypothalamus in the brain, use of medications, excessive caffeine intake, or not drinking enough water.

Treatment for polydipsia is guided by a general practitioner, endocrinologist or psychiatrist, and may involve the use of antidiabetics, antidepressants or antidiuretics. Treatment varies depending on the underlying cause.

Main symptoms

The main symptoms of polydipsia are:

Excessive thirst, even after drinking lots of water
Increased urination
Dry mouth
Headache
Muscle cramps or spasms
Dizziness or mental confusion

These symptoms appear mainly because polydipsia leads to excessive water intake, which can cause an electrolyte imbalance in the blood. Specifically, excessive fluid intake can cause a decrease in sodium, leading to hyponatremia.

If polydipsia is caused by diabetes mellitus, other symptoms may be present, such as excessive hunger, slow healing or frequent infections.

Confirming a diagnosis

A polydipsia diagnosis is confirmed by a general practitioner, endocrinologist or psychiatrist, who will start by evaluating the patient's symptoms, health history, lifestyle habits and previous laboratory tests.

To confirm the diagnosis and identify the underlying cause of polydipsia, the doctor will order testing like bloodwork to check blood glucose levels and electrolyte levels, and blood osmalility, a 24 hour urine test, and a urine R&M. Read more about the 24 hour urine test and hour it is performed.

The doctor may also order other tests, such as a CT scan or MRI of the brain, to assess whether there are any changes in the hypothalamus.

Possible causes

The main causes of polydipsia are:

Diabetes mellitus or diabetes insipidus
Changes in the hypothalamus, which controls the thirst mechanism
Diseases such as Langerhans cell histiocytosis and sarcoidosis
Dehydration from not drinking enough water
Excessive consumption of salt in food or drinks containing caffeine or alcohol
Psychological disorders, such as anxiety or schizophrenia

Other causes of polydipsia are not drinking enough water after massive fluid losses, which can happen with conditions like diarrhea and vomiting, It can also occur with certain medications, such as thioridazine, chlorpromazine and antidepressants.

Furthermore, polydipsia can also be caused by mental disorders, such as anxiety, schizophrenia, psychotic depression, bipolar or schizoaffective disorder, for example.

Types of polydipsia

There are different types of polydipsia, which vary depending on the underlying causes. These can include:

1. Primary or psychogenic polydipsia

Primary polydipsia or psychogenic polydipsia occurs when excessive thirst is caused by a mental disorder, mainly schizophrenia.

Other mental disorders that can also cause polydipsia are anxiety, psychotic depression or bipolar disorder.

2. Drug-induced polydipsia

Drug-induced polydipsia is caused by taking certain medications, such as diuretics, vitamin K, and corticosteroids. These medications can cause polyuria, which is the need to urinate several times a day.

3. Compensatory polydipsia

Compensatory polydipsia occurs due a drop in antidiuretic hormone levels. This hormone is responsible for the reabsorption of water in the kidneys, and low levels can lead to excessive urine losses. The body will stimulate thirst as a result, in order to replace fluid losses, leading to polydipsia.

Treatment options

Treatment for polydipsia should be guided by a general practitioner, endocrinologist or psychiatrist. The type of treatment ordered varies according to the underlying cause of polydipsia.

For polydipsia caused by diabetes mellitus, antidiabetics (like metformin or insulin) may be prescribe. The doctor may also advise lifestyle changes, like a low-sugar diet and exercise.

For polydipsia caused by diabetes insipidus, a endocrinologist may prescribe vasopressin analogues, such as desmopressin, which is a synthetic antidiuretic hormone. This medication works by preventing urine production by the kidneys when fluid levels are low in the body.

For polydipsia caused by psychological disorders, a psychiatrist may prescribe antidepressant medications, anxiolytics and psychological therapy to help the person recover from the compulsion to drink excessive amounts of water.

Is drinking a lot of water harmful?

The main risk of drinking excessive amounts of water is developing hyponatremia. This condition is associated with an excessive loss of sodium through urine, leading to low sodium levels in the blood. It can cause headaches, dizziness, drowsiness and even more serious conditions, such as seizures and coma.