The use of psychopharmaceuticals to enhance human mental functioning such as cognition and mood has raised a debate on questions regarding identity and authenticity. While some hold that psychopharmaceutical substances can help users to ‘become who they really are’ and thus strengthen their identity and authenticity, others believe that the substances will lead to inauthenticity, normalization, and socially-enforced adaptation of behaviour and personality. In light of this debate, we studied how persons who actually have experience with the use of psychopharmaceutical medication would view their ‘self’ or their authentic personal identity in relation to the use of medication. We have interviewed a number of adults diagnosed with ADHD and discussed their experiences with medication use in relation to their conceptions of self and identity. In the first part of this paper we illustrate that the concepts of identity and authenticity play an important and sometimes problematic role in experiences of ADHD adults. This shows that the question about identity and psychopharmacology is not merely an ‘academic’ issue, but one that influences everyday lives of real people. In order to answer the question whether psychopharmaceuticals threaten personal identity and authenticity, more than empirical research is needed. We also need to analyse the concepts of personal identity, authenticity and self: what do we mean when we are using statements as ‘a way of living that is uniquely our own’, ‘our true self’, or ‘who we really are’? In the second part of this paper we discuss two important philosophical views on personal identity, authenticity and self: the self-control view as elaborated by Frankfurt, and the self-expression view as proposed by Schechtman. We compare these with the experiences of our respondents to see which view can help us to understand the diverse and often conflicting experiences that people have with medication for ADHD. This will contribute to a better understanding of whether and in which cases personal identity and authenticity are threatened by psychopharmacology.