In this thesis I investigate the notion of harm in psychiatry. The question is whether a person is harmed, and in what way, by a particular condition that is of psychiatric relevance. In other words, I explore whether harm should be one of the criteria to focus on in psychiatric practice - in the process of psychiatric assessment, diagnosis, and treatment of patients. If so, how should we think about, define and conceptualize harm to fit the needs of this context. What harm in psychiatry entails becomes a bit clearer once we consider how it entered into the psychiatric context. The notion of harm entered psychiatry in the 1970s during the process of depathologisation of homosexuality – the removal of homosexuality from the list of mental disorders. The argument was that mental disorders are conditions that harm a person that has them. Seeing as homosexuals are not harmed in virtue of their condition, they are not suffering from a mental disorder. In years following the APA’s decision to depathologize homosexuality, harm would be included in authoritative diagnostic manuals and would be featured in the discussion on mental disorders, which has been a central discussion in philosophy of psychiatry for the last forty years. In this work I argue that harm is an important criterion in psychiatry, rightfully deserving of our attention. Harm is relevant both in theory and practice as one of the criteria that seriously considers the patient’s point of view as we have seen in the case of depathologizing homosexuality. Even though the traditional debate on mental disorders presents the conceptual and methodological landscape of our analysis, in recent years the debate has been strongly objected to. The lion’s share of the criticism has been directed towards traditional philosophical methods like conceptual analysis. Further objections are directed at the methodology of the discussion on mental disorders, questioning the nature of the concept, the intuitions and goals of the discussion and whether we are investigating one concept or many. I take these objections to be justified and side with metatheoretical innovations in the discussion on mental disorders that have come about in recent years (Bortolotti, 2020; Ereshefsky, 2009; Murphy, 2006; Schwartz, 2007a). To place harm in the context of these methodological novelties in philosophy of psychiatry I take Dominic Murphy’s (2006) taxonomy that builds on the traditional positions in the discussion, objectivism and constructivism, by adding the variants – conservativist and revisionist. My contribution to the discussion is an addition to Murphy’s taxonomy, a position which I call “compassionatism”. It is the view that concepts that capture the first-person perspective are and should remain crucial in psychiatry. This includes concepts such as harm, well-being, welfare, suffering and so on. I believe that in highlighting compassionist concepts and making them salient we are bringing attention to a key element of psychiatric practice – the patient’s perspective. I focus on harm as one of these compassionatist concepts. I take the revisionist route of compassionatism in arguing that our analysis of harm should be constructive and normative, rather than a descriptive project. We should decide on what we need and how we should think about harm rather than describe how harm is used in various psychiatric contexts. Our compassionatist concepts, specifically harm, should be constructed according to two principles. First, the concept should as fully and as faithfully capture the patient’s perspective. Second, it should do so while adhering to the precepts of the psychiatric practice. To come to the concept of harm I use an explicationist methodology inspired by Rudolf Carnap (1962). The method consists in taking an imprecise concept (explicandum) and turning it into a precise concept (explicatum) which would fit particular needs and interests. To begin I use the idea of harm in bodily medicine which, I argue, consists in the inability to achieve and maintain homeostasis. I try to transpose this view to psychiatry, being also wary of the differences between them and challenges that such a move would pose. I propose what I consider to be a close approximate of this view in psychiatry. I argue that harm in psychiatry consists in inadequate resources in dealing with the problems of living. I unpack each of the elements of the view – ‘inadequate’, ‘resources’, ‘dealing with’ and ‘problems of living’ showing what they mean and how they work together.