Decision aids help people make informed choices about health treatments or screenings. This review found that decision aids improve knowledge, accurate risk perception, and decision-making clarity compared to usual care. They also reduce decisional conflict and increase patient involvement in decisions. Decision aids may lead to more informed choices that align with personal values and improve satisfaction with decisions. However, the evidence is not strong enough to confirm long-term effects on adherence or healthcare costs. The review included 105 studies with 31,043 participants, focusing on decisions about surgery, screening, genetic testing, and medication. Decision aids were compared to usual care, general information, or no intervention. The review found that decision aids improved knowledge, accurate risk perception, and decision-making clarity, but the evidence for other outcomes was less strong. The review also found that decision aids may reduce the number of people choosing invasive procedures in favor of less invasive options, but this effect was not statistically significant in all cases. Overall, decision aids appear to be beneficial for patients facing health treatment or screening decisions.Decision aids help people make informed choices about health treatments or screenings. This review found that decision aids improve knowledge, accurate risk perception, and decision-making clarity compared to usual care. They also reduce decisional conflict and increase patient involvement in decisions. Decision aids may lead to more informed choices that align with personal values and improve satisfaction with decisions. However, the evidence is not strong enough to confirm long-term effects on adherence or healthcare costs. The review included 105 studies with 31,043 participants, focusing on decisions about surgery, screening, genetic testing, and medication. Decision aids were compared to usual care, general information, or no intervention. The review found that decision aids improved knowledge, accurate risk perception, and decision-making clarity, but the evidence for other outcomes was less strong. The review also found that decision aids may reduce the number of people choosing invasive procedures in favor of less invasive options, but this effect was not statistically significant in all cases. Overall, decision aids appear to be beneficial for patients facing health treatment or screening decisions.