Additional Study Information: We are seeking adolescents ages 13-17 to participate in a study on anhedonia. Anhedonia is the reduced ability to feel pleasure or enjoy things, and is a key feature of depression and other mental illnesses. If you believe your child is experiencing anhedonia, they may be eligible to participate in this study. If your child participates in this study, we will ask that they answer questions about themselves in an interview with our study team and complete some tasks during an electroencephalogram (EEG) test. We will also ask that your child fill out questionnaires about their thoughts and feelings. Participants may be compensated up to $229 for completing the entire study.