Eur Arch Psychiatry Clin Neurosci (1996) 246:83-92 9 Springer-Verlag 1996 Manfred Rihs 9 Christian Mfiller 9 Pierre Baumann Caffeine consumption in hospitalized psychiatric patients Received: 6 February 1995 / Accepted: 1 September 1995 Abstract A total of 98 consecutively admitted psychi- atric inpatients were asked for their daily consumption of coffee, tea and other products containing caffeine. Calcu- lation of the corresponding daily caffeine intake was per- formed using data from the literature and from caffeine measurements carried out in different coffee and tea prepa- rations in the hospital. Of the patients 13% presented a high (_> 750 mg daily) caffeine consumption before hospi- talization. The average caffeine consumption per day de- creased from 405 mg before to 332 mg during hospitaliza- tion (P < 0.04), but the before and during hospitalization caffeine consumptions were highly correlated (rho = 0.651; P < 0.00001). The decrease in caffeine consump- tion seems to be influenced by a lower availability of caf- feine at hospital. Among the diagnostic groups (DSM-III- R criteria), the caffeine intake was highest in schizophre- nia and lowest in anxiety and major depression patients. Patients under a neuroleptic treatment before admission presented a higher caffeine intake. At hospital the high caffeine users showed the highest score on the factor de- pression (Hopkins Symptom Checklist; HSCL-58). How- ever, the influence of other factors, such as weight and cig- arette consumption, which correlated also with the caf- feine intake (rho -- 0.359; P < 0.001; and rho = 0.83; P < 0.00001, respectively), have also to be considered. Our data suggest that inquiry into caffeine consumption should be included routinely for psychiatric patients, e.g. at ad- mission, because patients with a psychotic disorder un- dergo a higher risk for an excessive caffeine consmnption. Key words Caffeine consumption - Smoking 9 Psychiatric patients 9 Psychopathology - Psychiatric hospital Manfred Rihs I 9 Christian Mtiller 2 9 Pierre Baumann ([~) Unit6 de biochimie et psychopharmacologie clinique, D6partement universitaire de psychiatrie adulte (DUPA), Site de Cery, CH-1008 Prilly, Lausanne, Switzerland Present addresses: Externer Psychiatrischer Dienst des Kantons Aargau, K6nigsfelden, CH-5201 Brugg, Switzerland 2Herrengasse 23, CH-3011 Berne, Switzerland Introduction Caffeine is a widely used psychoactive substance, present in food, but also in pharmaceutical preparations (Dews 1984; Paul and Skolnick 1981; Bruce and Lader 1986). Caffeine is discriminated by humans in doses as low as 10-56 mg (Griffiths et al. 1990). Single doses (100-400 mg) of caffeine may produce slight increases in elation, positive mood and amphetamine-like effects (Goldstein et aI. 1965; Oliveto et al. 1990; Bruce et al. 1986), but also aversive effects such as increased anxiety and dysphoria (Stem et at. 1989) in healthy volunteers. Regular caffeine consumers experience less effects after 500 mg, due to tolerance. Furthermore, withdrawal effects are regularly seen in habituated caffeine users (Goldstein and Kaizer 1969). They are characterized by an onset latency of 19 h, peaking on days 1 and 2, and a progressive decrease over the next 5 or 6 days, and they consist of increased headache, sleepiness, laziness and decreased alertness and activeness (Griffith et al. 1986). Neither the Swiss nor the European average caffeine consumption of the general adult population is exactly known. American investigations based on data obtained in 1977 and 1972 showed a mean daily intake of about 200 rag, or 3 mg/kg body weight, per adult (Gilbert 1976; Graham 1978; Barone and Roberts 1984). Three studies undertaken in the UK showed mean daily caffeine con- sumption varying between 359 and 621 mg [Galliano 1982 (unpublished; cf Table 5); Bruce et al, 1986; Scott et al. 1989]. Marketing surveys of the per capita consumption of green coffee beans in 1972 (Pan American Coffee Bu- reau) and of tea leaves in 1970 (International Tea Com- mittee) suggest a similar pattern of consumption of the American (6.3/0.2 kg) and the Swiss (6.2/0.2 kg), but not of the UK, population (2.2/3.8 kg). Greden et al. (1981) defined three groups of coffee drinkers: low (0-249 mg per day), moderate (250-749 mg) and high caffeine consumers (750 mg or more). Of 83 psychiatric inpatients 22% were found to be high caffeine