Acute and Long-Term Antidepressant Treatment Success in Adolescents With Anxiety (AtLAS-A)

Inclusion Criteria: * Written, informed assent and consent. * Patients, parent/guardian/LAR must be fluent in the English. * 12 to 17 years of age, inclusive, at Screening. * Patients must meet DSM-512 criteria for generalized, social and/or separation anxiety disorder and/or panic disorder, confirmed by the MINI-KID. * Caregiver who is willing to consent to be responsible for safety monitoring of the patient, provide information about the patient's condition, oversee the administration of the investigational product. * No clinically significant abnormalities on physical examination. * Negative pregnancy test at Screening in females. * Negative urine drug screen at Screening. * Sexually active patients must practice a reliable method of contraception (Section 15.0) that will continue for the duration of the study and for a minimum of 30 days following the end of study participation. Reliable methods of contraception are defined below; other forms of contraceptives (pharmacological and/or non-pharmacological) are not accepted: 1. Surgical sterilization 2. Oral contraceptives (e.g. estrogren-progestin combination or progestin) 3. Transdermally-delivered contraceptives (e.g., Ortho-Evra), depot injections (e.g., Depo-Provera) 4. Vaginal contraceptive ring (e.g., NuvaRing), contraceptive implants (e.g., Implanon, Norplant II/Jadelle) 5. An intrauterine device 6. Diaphragm plus condom. Exclusion Criteria: * DSM-512 diagnosis other than generalized anxiety, social anxiety, separation anxiety or panic disorder(s) that is the primary focus of treatment. * A history of intellectual disability. * Suicide risk as determined by either: (1) any suicide attempt within the past 6 months and/or (2) significant risk at Visit 1 (Screening) or Visit 2 (Baseline), as judged by the Investigator. * Allergy, intolerance, non-response or hypersensitivity to escitalopram or duloxetine. * Subjects taking other medications that require a taper or washout of more than 5 days. * Patients who have initiated/terminated psychotherapy/behavior therapy within 1 month before Visit 2 (Baseline), or who plan to initiate/change said therapies during the course of the study will be excluded; if the patient is engaged in psychotherapy, it must have been stable for 1 month prior to baseline. * A clinically-significant medical illness. * QTc \>450 in males / \>460 in females (prolonged QTc based on American Heart Association recommendations for Standardization and Interpretation of the EKG81 * Alcohol or substance use disorder within the past 6 months (nicotine use is permitted). * Positive urine pregnancy test/pregnancy or breast feeding. * A positive urine drug screen. * Patients who are unable to swallow capsules.