INTRODUCTION
Caffeine is the most widely consumed psychoactive substance in the world. Psychiatric symptoms and disorders can be associated with its excessive use. DSMIV TR lists several caffeine related disorders, eg-caffeine intoxication, caffeine induced anxiety disorder and caffeine induced sleep disorder. Other caffeine related disorders are caffeine withdrawal and caffeine dependence.
EPIDEMIOLOGY
Caffeine is contained in drinks, foods, prescription medicines and over the counter medications. An adult consumes about 200mg of caffeine per day on an average and 20-30% of adults consumes more than 500mg of caffeine per day. A cup of coffee contains around 100 to 150mg of caffeine; tea about one third as much. Many over the counter medications contains one third to one half as much caffeine as a cup of coffee and some migraine medication and over the counter medicines contains more amount of caffeine than a cup of coffee. Cocoa, chocolate and soft drinks also contain significant amount of caffeine, enough to cause some symptoms of caffeine intoxication in small children when they ingest a candy bar or cola drink.
Caffeine consumption also varies by age. The average daily caffeine consumption of caffeine consumers of all age is 2.79mg/kg body weight. A substantial amount of caffeine is consumed by small children also.
COMORBIDITY
Persons with caffeine related disorders are more likely to have additional substance related disorders than are those with out diagnosis of caffeine related disorders. About two third of those who consume large amounts of caffeine daily also use sedative and hypnotic drugs.
ETIOLOGY
After exposure to caffeine , continued caffeine consumption can be influenced by several factors, such as pharmacological effects of caffeine, caffeine's reinforcing effects, genetic predisposition to use caffeine and personal attributes of the consumer.
NEUROPHARMACOLOGY
Caffeine is more potent. The half life of caffeine in human body is 3-to 10 hrs, and the time of peak concentration is 30-60 min. Caffeine readily crosses the blood brain barrier. Caffeine acts primarily as an antagonist of adenosine receptors. Adenosine receptors activate an inhibitory G protein and thus inhibit the formation of the second messenger cyclic adenosine mono phosphate (cAMP). Caffeine intake result in an increase in intraneuronal cAMP concentrations in neurons with adenosine receptors. Three cups of coffee are estimated to deliver the amount of caffeine which occupy about 50% adenosine receptors
High doses of caffeine can affect the dopaminergic and noradrenergic system. Dopamine activity is enhanced by the caffeine activity, so it may be the reason of exacerbation of clinical symptoms in patients with schizophrenia in increased caffeine intake.
Subjective effects and reinforcement
Single low to moderate amount of caffeine can produce a subjective wellbeing in human beings and is generally indicated as pleasurable. caffeine causes increase in energy, motivation, capacity to work and concentration. Caffeine decreases the sleep and fatigue. 300-800mg of caffeine may lead to anxiety and nervousness. At low doses it act as a reinforce and this effect contribute to the regular use of caffeine.
Genetics and caffeine use.
Some genetic predispositions are present in caffeine use. Monozygotic and dizygotic twins have high concordance. It is more in monozygotic twins than dizygotic twins and heritability ranging from 33 to 77 percent.
Age, sex and race.
Studies suggest that middle age people use more caffeine, there is no much difference in caffeine use among male and females.
Special populations
Smokers consume more caffeine than non smokers. Studies shown that the higher rates of caffeine use in psychiatric patients populations than the general population. Patients who have anxiety disorders tend to use less amount of caffeine.
Effects on cerebral blood flow.
Caffeine result in cerebral vasoconstriction, with a resultant decrease in cerebral blood flow . cerebral blood flow improves after withdrawal from the caffeine. Many other studies reveals that caffeine can cause coronary artery constriction.
DIAGNOSIS
Diagnosis of caffeine related disorders and caffeine dependence are depend primarily on the comprehensive history of the patient. The history should cover whether the patient has experienced any symptoms, pattern of caffeine intake, whether the person had tried to stop the intake of caffeine etc.
The differential diagnosis of caffeine related disorders are anxiety disorders, panic disorders with or without agora phobia, bipolar II, ADHD, and sleep disorder. The differential diagnosis should include the intake of OTC, anabolic steroids, and stimulants such as amphetamines. A urine sample is needed to screen for other stimulants.
CAFFEINE-RELATED DISORDERS (DSM IV TR CRITERIA)
Caffeine-Induced Disorders
305.90 Caffeine Intoxication
292.89 Caffeine-Induced Anxiety Disorder
292.85 Caffeine-Induced Sleep Disorder
292.9 Caffeine-Related Disorder NOS
I. Caffeine intoxication
Diagnostic criteria includes the recent consumption of caffeine, usually more than 250mg. common symptoms associated with caffeine intoxication are anxiety, psychomotor agitation, restlessness, muscle twitching, , psychophysiological complaints, nausea , dieresis, GIT upset, tingling in the fingers and toes. Consumption of more than one gram of caffeine can cause rambling of speech, confused thinking, cardiac arrhythmias, agitation, tinnitus and visual hallucinations.
DSM IV TR
A. Recent consumption of caffeine intake usually more than 250 mg(more than 2-3 cups of brewed coffee)
B. Five or more of following signs, developing during, shortly and after the caffeine use
- Restlessness
- Nervousness
- Excitement
- Insomnia
- Flushes face
- Dieresis
- GIT disturbances
- Rambling flow of thought and speech
- Tachycardia or cardiac arrhythmia
- Periods of inexhaustibility
- Psychomotor agitation
C. The symptom in criteria B causes significant distress or impairment in social, occupational, or other important areas of functioning.
D. The symptoms are not due to general medical conditions and are not better account for any other mental disorders.
II. Caffeine induced anxiety disorder
Caffeine induced anxiety disorder can occur during caffeine intoxication. The anxiety related to caffeine use can resemble the generalized anxiety disorder. The patient may be perceived ad wired, over talkative, and irritable. They may complaint of reduced sleep. Caffeine can induce and exacerbate panic attacks in persons with panic anxiety disorder.
III. Caffeine induced sleep disorder.
Caffeine induced sleep disorder can occur in acute intoxication. Caffeine is associated with delay in falling sleep, inability to remain in sleep, and early morning awakening.
IV. Caffeine related disorder not otherwise specified.
Caffeine dependence and caffeine withdrawal are not included in DSM IV TR. They are included in the classes- caffeine related disorder NOS
CLINICAL FEATURES
Signs and symptoms
After the ingestion of 50-100mg of caffeine , common symptoms includes increased alertness, a mild sense of wellbeing and a sense of improved verbal and motor performance. Caffeine ingestion is also associated with dieresis, cardiac muscle stimulation, increased intestinal peristalsis, increased gastric acid secretion and increased blood pressure.
Caffeine use and nonpsychiatric illness
- There are significant risks from caffeine use. They are cancer, heart diseases, reproduction problems etc.
- Caffeine use is contraindicated in generalized anxiety disorder, panic disorder, primary insomnia, pregnancy, gastro esophageal reflux disease.
- Caffeine increases the blood pressure.
- There is association between caffeine consumption and low birth weight babies.
TREATMENT
- Analgesics such as aspirin can use to control the head ache because of caffeine withdrawal. Rarely patients need benzodiazepines to manage the withdrawal effects. If benzodiazepines use for this purpose it should use invery small doses for 4-7 days.
- Person should recognize all sources of caffeine in his diet and control the caffeine intake. Because caffeine is use in the beverage form, it can be substituted with beverages which are noncaffenated. The patient should avoid stopping the caffeine intake abruptly, caffeine intake should taper first before proceed to the complete abstinence.
REFERENCES
- Kaplan HI, Sadok BJ. Synopsis of psychiatry-behavioural science or clinical psychiatry.9th edn. Hong Kong.William and Wilkinsons publications. 1998.
- GelderM,Gath D,Mayou R,Cowen P. New oxford text book of psychiatry. 4th edn.Oxford. Oxford university press.2004
- Ahuja N.A short text book of psychiatry. 5th edn. New Delhi. Jaypee brothers medical publishers.2004.
- Townsend MC. Psychiatric mental health nursing. 3rd edn. Philadelphia. FH Davis publishers
