Interventions aimed at enhancing psychiatric patients' outpatient treatment adherence frequently include informal coercion such as inducements, and threats of negative sanctions. Little is known about patients' subjective perspective concerning these practices. This study examined the perceived coercion, and also the appraisal of the fairness and effectiveness of the treatment. A total of 187 psychiatric patients with different diagnoses were interviewed using a structured questionnaire that included socio-demographic and clinical data, insight into illness (ITAQ), psychopathology (BPRS), functioning (GAF) and a modified version of the MacArthur Admission Experience Survey (AES) as a measure of perceived coercion, fairness and effectiveness. Bivariate correlations and logistic regression analyses were used to identify the influencing factors on the outcome variables. Perceived coercion was associated with experience with informal coercive treatment pressures (OR 2.5–2.9; P < 0.05), and a main diagnosis of a schizophrenic disorder (OR 3.8; P < 0.001). Experience with informal coercion was inversely associated with fairness (OR 0.3–0.4; P < 0.05), but not with effectiveness. Patients with more insight into their illness indicated higher fairness and effectiveness concerning the procedures for enhancing their treatment adherence (OR 3.1; P < 0.01). Insight into illness was not associated with perceived coercion. This might indicate that enhancing insight using psycho-educational approaches and high transparency when applying informal coercive practices could improve patients' appreciation for these procedures. They could probably cope better with perceived coercion when understanding its purpose, and when they perceive they are being treated fairly.