This paper is concerned with how, in contemporary Middle Eastern societies, psychiatric categories circulate in the wider society and are appropriated, challenged, and reconfigured through interactions with other conceptualizations of mental wellbeing, particularly religious-based ones. In Egypt, the last three decades have seen increasing debates around the relationship between mental disorders and religion. Carried out among psychiatrists, religious scholars, and Qur’anic healers (the practitioners of a revivalist form of exorcism who sometimes claim expertise in treating mental disorders), these debates embody a contemporary rethinking of human psychological constitution, of what counts as mental disorder, and of the role of religion in one’s life and, more generally, in modern societies. They have emerged in a historical conjecture characterized by both the Islamic revival and by shifts and tension inside psychiatry between biological and psycho-social explanatory frameworks. Spanning and overlapping psychiatric and religious domains, these debates point to the salience of and the anxieties around the question of proper boundaries between science and Islam in postcolonial Egypt. Drawing on ethnographic research among psychiatrists, Qur’anic healers, and their patients, in this presentation I focus on one aspect of these debates, concerning the relationship between depression (ikti’āb) and weak faith (īmān ḍa‘īf). While few Egyptians claim that a weak faith in God directly causes depression, the idea that strong faith is the best prophylactic against this mental disorder is widely spread in Egyptian society and especially among Qur’anic healers who persistently disseminate it among their patients. To counteract psychiatrists’ criticism based on defining depression as a neurochemical brain imbalance, many Qur’anic healers, as other Egyptians, re-classify depression into two types: psychological depression, influenced by a person’s religiosity and pathological depression, caused by brain imbalances. Unwittingly employing older psychiatric conceptualization of depression, they articulate them with Islamic-based conceptions of faith, religious activity, and the human soul. At the same time, a number of psychiatrists concerned with forging an Islamic psychiatry, have attempted to integrate religious practices in their therapies, proposing their own understandings of the links between depression and faith. These debates around the relationship between depression and faith, I argue in this paper, reveal not a clear-cut relation between the psychiatric and the religious fields, but a dynamic process of rethinking and redefining what is physically versus what is morally treatable and of questioning the boundaries between what counts as religious and what as scientific in contemporary Egypt