Skip to main content

Verified by Psychology Today


When Dehydration Leads to Mental Health Problems

Can a person hallucinate when dehydrated?

Key points

  • Being dehydrated might be associated with first episodes of psychosis, such as having hallucinations.
  • Some people diagnosed with schizophrenia and other psychotic conditions tend to feel excessively thirsty.
  • To help patients manage excessive thirst, carers need to be aware of the danger of water intoxication and related early deaths.
  • Appropriate water consumption is an important contributor to mental health, but excessive water consumption is dangerous.

People are often encouraged by doctors, healthcare professionals, and public service messages to drink enough water each day, but did you know that being dehydrated could be associated with first episodes of psychosis (having hallucinations)[1] and that some people diagnosed with psychotic conditions such as schizophrenia tend to feel excessively thirsty?[2-4] There is a complex relationship between water consumption, psychosis, and health outcomes such as early death.[4] Caretakers of people with psychotic disorders, or people at risk of them, need to be aware that dehydration, excessive thirst, and water intoxication are significant problems that need careful support and specialist help.

Dehydration and first episodes of psychosis

Psychiatrists recently reported the case of a patient with no prior history of a mental illness who was severely dehydrated and arrived at a hospital emergency department with concerning symptoms.[1] The patient’s symptoms included auditory hallucinations of voices, music, and singing, and the patient shouted out words suggestive of disorganised speech, both of which are possible signs of psychosis. The patient also had tachycardia, which is a heart rate of over 100 beats per minute. After treatment with medication and rehydration through intravenous fluid transfer, the patient was discharged after their psychotic symptoms subsided. The authors theorised that the patient might have suffered from psychotic symptoms because dehydration is associated with disturbances in certain substances within the bloodstream (hyponatremia or hypernatremia, which concerns sodium levels) and the authors theorised that the imbalance, in turn, affected the patient’s brain and neurological functioning.[1]

The authors’ conclusion suggests that both dehydration and water intoxication could be associated with first episodes of psychosis, but future research is needed to explore this idea using longitudinal methods that can clarify causality. It could be that people suffering from psychotic symptoms tend to drink less water because of psychological reasons, remembering that psychosis can impair normal functioning such as self-care, therefore it might be the case that among some patients dehydration is a correlate—not a cause—of the psychosis.

Excessive thirst, water intoxication, and psychosis

Among patients with a prior history of psychosis, the relationship between water consumption and psychosis might be more complex, with the research showing that some people with psychosis tend to feel excessively thirsty and this leads them to drink large amounts of water to a point where water intoxication is a significant risk. Some authors suggest, for example, that some medication taken by people with psychosis could impair their body’s ability to process water, leading to a sodium imbalance.[2] Drinking an excessive amount of water has been associated with some types of antipsychotic medication, and such water intoxication has been noted among schizophrenic patients who suffer a relapse.[3] This suggests that, in some cases, antipsychotic medication could make people feel excessively thirsty and compel them to drink amounts of water that are toxically high. Therefore, among patients diagnosed with a psychotic disorder, water intoxication can be problematic.

Dehydration is also a problem among patients with psychosis, with a study of 259 patients with schizophrenia finding that 7 percent were dehydrated and most needed fluids treatment to recover.[4] The water imbalances among patients with psychosis could be associated with antipsychotic medication and organ functioning, or behaviours brought on by that medication such as the urge to drink water.

A review discussed evidence that severe water intoxication leads to 5 to 15 percent of fatalities among some patients with psychosis, and evidence that schizophrenic patients with primary polydipsia (feeling excessively thirsty) tend to die 10 years earlier than other schizophrenic patients even if they did not have water intoxication.[5] The authors discuss the implications of antipsychotic medication for water excretion but argue that such medication does not fully explain the fatality rates.[5] The reasons for the primary polydipsia are thus not fully understood and might thus not entirely be down to antipsychotic medication. It is not clear what proportion of psychotic patients feel excessively thirsty because they are dehydrated, what proportion feel thirsty because of antipsychotic medication, and what proportion have excessive thirst because of psychological reasons.


It is important for clinicians and family members of patients to be aware that a proportion of patients with schizophrenia or other psychotic disorders suffer from excessive thirst, and that managing their hydration levels requires an understanding of the risks of water intoxication and awareness that water intoxication is a significant contributor to deaths among patients with schizophrenia.[4] People at risk of psychosis, and the general population, need to be aware that appropriate hydration is important to mental health and that being very dehydrated might be associated with hallucinations or other psychotic symptoms.


[1] A Unique Case of Dehydration-Related Psychosis: Witnessing a Mirage in the City

[2] Hyponatremia in Psychosis

[3] Polydipsia with water intoxication in treatment-resistant schizophrenia

[4] Abnormal physiological conditions in acute schizophrenic patients on emergency admission: dehydration, hypokalemia, leukocytosis and elevated serum muscle enzymes

[5] The Assessment and Treatment of Water Imbalance in Patients with Psychosis

More from Caroline Kamau Ph.D.
More from Psychology Today