Summary Adherence with psychotropic medication is at least at poor as adherence with medication for physical health problems. There has been an assumption this was due to loss of insight resulting from psychiatric disorders themselves. Consequently, interventions have focussed on treating the underlying psychiatric disorder and generating psychological strategies to promote awareness. Recent surveys of patient preferences for information and involvement in health care decisions highlight that most individuals want to participate in the process of medical care. Patients often have strong pre-existing beliefs about different therapeutic options. This is supported by the self-determination theory which distinguishes between autonomous behaviour and behaviours that are influenced by external forces. When considering the patient perspective in medication adherence, it is useful to consider the self-medication hypothesis. This can equally be applied to prescribed and non-prescribed drugs. The self-medication hypothesis states that patients decide to start, adjust or stop prescribed medication according to perceived health needs. Such decisions are often conducted intentionally and rationally, given the information available to the patient and their understanding of their condition. In this narrative review, the evidence for and against intentionality in psychotropic adherence behaviour is examined. Studies of compliance and related predictors are examined in depression, schizophrenia and bipolar affective disorder. Results suggest that although concordance depends on patient, illness and clinician factors, patient choice is usually the final common pathway. Illness severity and insight is important in some cases but can act in concert with cognitive factors. Individuals appear to prefer to take medication “as required” (symptomatically) rather than prophylactically. Significant influences upon self-medication habits are prior health beliefs, medication attitudes, adverse effects and adequacy of communication from the health care professional. The self-medication hypothesis applied to prescribed psychotropic medication should assist rather than heed clinicians in improving adherence by taking a patient centred approach and where possible promoting patient autonomy.