Aims of Study: Substance use disorder (SUD) is a very complex and important problem involving many biological, mental and social impacts on the user, their family and the community. This study was conducted to determine of negative effects on the lives of people, functioning and marital adjustment of patients with SUD. Participants: The sample of the research has been consisted of 309 patients. Method: This descriptive study was conducted at the Alcohol and Substance Addiction Treatment and Education Center (ASATEC) outpatient clinic. The data has been collected by using The Information Form, Short Functional Rating Scale (SFRS) and Dyadic Adjustment Scale (DAS). Outcomes: It was found that 19.4% of the patients were adversely affected by their education life, the divorce rate was increased and 44% were  negative impact on economic status and on their working lives. It was also determined that 41.7% of patients had physical health deteriorated and 49.2% of them had attempted suicide, 81.9% had decreased sexual desire due to substance use, 25.2% had the wrong sexual experience and 69.6% were violent behavior while under substance effect, 19.1% had the contagious disease. In this study, DAS total mean score of the patients was found to be 76.65 + 32.48 and that of SFRS was 1.93 ± 0.80. Conclusions: As a result, it has been determined that substance use disorder negatively affects the lives of patients in many ways, and patients’ functionalities and marital adjustment are low. Implications: Effective multisectoral policies should be developed to treat and rehabilitate people with substance use disorder