Introduction. -Fasting during the Ramadan month is a cornerstone of Islam. Several disorders of the chronobiological rhythms occur during this month and impact on mood. Through this paper the authors provide a literature review of the impact of fasting on patients with bipolar disorders. Materials and subjects. -A literature review using Mesh keywords through Medline database. From 1970 to 2011, articles in French and English were selected. Results. -Circadian rhythm refers to the approximately 24-hour cycles that are generated by an organism. Most physiological systems demonstrate circadian variations. Many hormones and other metabolisms, such as gastric pH, insulin, glucose, calcium and plasmatic gastrine, have been shown to exhibit circadian oscillation. The role of social rhythm in behaviors and its influence on circadian rhythms in humans is now obvious. It has been shown that the lack of concentration and irritability increased continuously during Ramadan month and reached its peak at the end of the month. Mood and vigilance are significantly decreased during the fasting month. Several authors have stated that the course of bipolar illness may be affected by the changes in social rhythm that occur during Ramadan (fasting month). Studies which have been devoted to this topic are sparse. Kadri et al., in 2000, studied 20 bipolar patients during the fasting month of Ramadan of 1417 (Hegirian calendar, corresponding to January 1997). Diagnosis of bipolar disorder was made according to ICD-10 criteria. Patients were assessed during the week before Ramadan, the second and the fourth weeks of the fasting month and the first week after its end, with the Hamilton Depression and Bech-Rafaelsen scales. The plasma concentration of lithium was also assessed. The main finding of the study was that 45% of the patients relapsed, 70% during the second week, and the remaining patients at the end of Ramadan. These relapses were not related to plasma concentration of lithium. Most of the relapses were manic (71,4%). Patients who did not relapse had more insomnia and anxiety during the second and third weeks of the study. The side effects of lithium increased and were seen in 48% of the sample, mostly dryness of the mouth with thirst and tremor. However, Farooq et at. in 2006 studied 62 bipolar patients during the fasting month of Ramadan 1427 (from 25 September to 24 October 2006). Serum lithium, electrolytes, Hamilton Depression Rating Scale (HDRS) and Young Mania Rating Scale (YMRS) were assessed, one week before Ramadan, mid Ramadan and one week after Ramadan. The side effects and toxicity were measured by symptoms and signs checklist. There was no significant difference in mean serum lithium levels at three time points. The scores on HDRS and YMRS showed significant decrease during Ramadan (F=34,12, P=0,00, for HDRS and F=15,6, P=0,000 for YMRS). Also the side effects and toxicity did not differ significantly at the three point's assessment. Conclusion. -All physiologic parameters are influenced by the circadian rhythm, which is influenced in its turn by the food rhythm. So far, the results of these two main studies, with opposite results, do not help us advise bipolar patients to fast or not to fast. Other studies in this field are badly needed. (C) L'Encephale, Paris, 2013.
