Caffeine-induced psychosis is a relatively rare phenomenon characterized by psychotic symptoms such asdelusions,paranoia, andhallucinations.[2][3] This is caused by an overuse ofcaffeine and which can occur in otherwise healthy people. Caffeine may also worsenpsychosis in people suffering fromschizophrenia.[4] This can happen with ingestion of high doses of caffeine or when caffeine is chronically abused. However, there is a limited amount of evidence that confirms this[clarification needed].[4][5][6]
Psychosis refers to a collection of symptoms that affect the mind, characterized as a loss of contact with reality. During an episode of psychosis, a person's thoughts and perceptions are disrupted and they may have difficulty recognizing what is real and what is not. This state of mind may be caused by a range of mental illnesses (schizophrenia,bipolar disorder), physical illnesses (Parkinson's disease,Alzheimer's), and some substances such asstimulant drugs.
While rare, caffeine-induced psychosis has been reported in both clinical studies and case reports. TheDiagnostic and Statistical Manual of Mental Disorders, Fifth Edition– Text Revision (DSM-5-TR) outlines five caffeine-related syndromes,[7] includingcaffeine-induced anxiety disorder,caffeine-induced sleep disorder, and unspecified caffeine-related disorders, under stimulant-related diagnostic codes. TheInternational Classification of Diseases, Tenth Revision (ICD-10)[7] classifies disorders associated with caffeine more broadly, as "mental and behavioural disorders due to use of other stimulants, including caffeine".[7]
Several case studies and reviews have suggested that excessive caffeine intake may provoke psychotic or manic symptoms in vulnerable individuals.[7][8][9] Caffeine may also worsen recovery in patients with bipolar disorder or pre-existing psychotic conditions, such as schizophrenia, which has led some clinical guidelines to recommend reducing or eliminating caffeine intake during psychiatric treatment, particularly formania.[2][9][10]
Some case reports suggest that psychotic symptoms can emerge in individuals without a history of mental illness after consuming high doses of caffeine.[2][7][10][11] Though not conclusively confirmed, it is hypothesized that caffeine may exacerbate underlying paranoid traits or lower the threshold for developingpsychopathology in those predisposed to psychosis. Symptom resolution following caffeine discontinuation has been observed in several cases, supporting the existence of caffeine-induced psychosis.[9]
Caffeine acts as an antagonist ofadenosine receptors, particularlyA1 andA2A receptors. Under normal conditions,adenosine inhibitsneurotransmission, which promotes sleep and suppressesarousal. By blocking these receptors, caffeine limits adenosine's inhibitory influence, which results in increased neuronal activity and the enhanced release of excitatoryneurotransmitters, such asdopamine andglutamate.
This mechanism contributes to improvedalertness,attention, and mood at moderate doses. However, high doses orchronic overuse may overstimulatedopamine pathways in the brain, particularly in areas like themesolimbic system, which are associated with the development ofpsychotic symptoms.[citation needed]
The elevated dopaminergic activity resembles the neurochemical abnormalities observed inpsychotic disorders to a lesser degree, and may trigger hallucinations, delusions, or manic symptoms, particularly in individuals who are genetically or biologically vulnerable.[9]
Additionally, caffeine-induced sleep deprivation, anxiety, and increased arousal can further exacerbate the risk of psychotic symptoms, either independently or in combination with other stressors or substances.[12]
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While caffeine is widely consumed for its stimulant effects, excessive intake has been associated with the onset of acute psychotic symptoms in individuals without prior psychiatric diagnoses, particularly under conditions ofsleep deprivation,stress, or concurrent substance use.[citation needed] A growing number of case reports have described caffeine-induced psychosis in otherwise healthy individuals, with symptoms typically resolving after caffeine cessation, although some cases necessitated psychiatric treatment.[citation needed]
Though a definitive causal relationship has not been established, caffeine's effect on dopamine levels may increase arousal and contribute to the onset of psychotic symptoms. Additionally, symptom improvement has been observed following caffeine reduction in individuals with pre-existing psychotic disorders. These findings suggest that individuals with a predisposition to psychosis may possess a lower threshold for developingpsychopathological symptoms in response to caffeine intake.[7]
People with schizophrenia may be more inclined to overuse caffeine for a variety of reasons. Many people with schizophrenia use caffeine to combat boredom or to fight the sedating effects ofantipsychotic medications. Many antipsychotics can also causedry mouth. Additionally, people with schizophrenia may experiencepsychogenic polydipsia (excessive thirst). These factors could increase the amount of caffeine one may consume.[13]
Eighty percent of people with schizophrenia smoke daily and are heavy smokers. Smoking tends to deplete much of ingested caffeine, so users with schizophrenia may consume more caffeine than others to make up for this.[13]
"Caffeine use can cause restlessness, nervousness, insomnia, rambling speech, and agitation",[13] worsening the symptoms of schizophrenia. "Caffeine is metabolized by theCYP1A2 enzyme and also acts as a competitive inhibitor of this enzyme. Thus, caffeine can interact with a wide range of psychiatric medications, including antidepressant agents, antipsychotic agents, antimanic agents, antianxiety agents, and sedative agents."[14]
A consumption of less than 250 mg of caffeine a day has been associated with better results on cognitive tasks in people with schizophrenia. However, more research still needs to be done to determine if the amount of caffeine that is safe to consume by schizophrenics (>250 mg/a day) is the same as the general population of people without schizophrenia.[15]
For people who have an addiction to caffeine, the best way to treat caffeine-induced psychosis is to gradually consume smaller amounts of it over a period of time.[citation needed] Withdrawal from certain drugs may worsen side effects of psychotic or mood disorders.[citation needed] For people who consume excessive amounts of caffeine without a prior psychotic disorder, a doctor may prescribeantipsychotics to help stop the effects of psychosis.[16]
