Background <p>Poor medication adherence among patients with schizophrenia increases hospitalization risk and impairs functioning, placing significant burdens on caregivers. Primary caregivers play a crucial role in influencing treatment adherence and recovery outcomes.</p> Methods <p>This cross-sectional study examined the relationships between caregivers’ illness perceptions, emotional expression, and patient medication adherence among 130 primary caregivers of schizophrenia patients at a northern Taiwan psychiatric hospital (January–June 2024). Researchers used the Medication Adherence Scale for Schizophrenia, the Illness Perception Questionnaire-Revised Version for Families of Patients with Schizophrenia, and the Five-Minute Speech Sample.</p> Results <p>The results revealed that caregivers with high emotional expression scored higher on identity, consequences, illness coherence, timeline cyclical, and emotional representations, whereas those with low emotional expression scored higher on timeline and personal control. Patients with low emotional expression caregivers demonstrated better medication adherence. Greater caregiver understanding of illness aetiology was associated with lower patient medication adherence.</p> Conclusions <p>These findings emphasize the need for further research examining whether mental health education for caregivers and emotional management interventions could improve patient medication adherence and condition stability.</p>