Attitudes toward medication (ATM) exert an influential role on compliance. Ninety-nine inpatients with schizophrenia were administered the Rating of Medication Influences scale (ROMI). Patients were also rated using: i) the Health of the Nation Outcome Scales, ii) the Global Assessment of Functioning scale, iii) the Clinical Global Impression, Severity scale, and iv) the WHO Quality Of Life assessment, Brief Version. Seventy-seven subjects (77.8%) completed the ROMI interview. Cluster analysis identified the following four clusters: i) Ambivalence (n=17; 22%); ii) Problems with Patient, Family, Alliance (n=11; 14.3%); iii) Medication Affinity, Positive Influence from Others (n=30; 39%); and iv) Illness, Medication, Label Distress (n=19; 24.7%). Clusters did not differ in demographic or clinical variables except for depressed mood and physical well-being, which were, respectively, lower and higher in patients with mostly negative ATM. Based on rater assessment, psychotic symptoms were related to negative ATM independently of their severity, and the family played a central role in the expression of negative attitudes. ATM were relatively independent of clinical and psychosocial variables. The existence, in each cluster, of both external and inner motivations underpinning ATM suggests that therapeutic interventions must take into account both patients and their broader living contexts.