The purpose of this study is to evaluate if a trauma treatment called Trauma Systems Therapy (TST) decreases children's mental health symptoms (such as acting out, not controlling their emotions, etc.) as a result of a traumatic event (or events). A traumatic event or events can include experiencing or witnessing violence, excessive bullying, war, car accident, serious injury, getting mistreated or anything else that makes one feel scared or frightened. Children/teens who experience traumatic events have been shown to be at higher risk of poor mental and physical health. Trauma can impact family life, school life and interpersonal relationships well into adulthood. Unfortunately, most children who have experienced traumatic events do not undergo treatment. Although promising treatments do exist, most do not address the complexity of trauma, particularly related to ongoing stress and threats to safety in their environments. One hundred and twenty eligible youth will be randomized to receive either treatment with TST at NYU's Child Study Center or trauma treatment as usual (TAU) at a community mental health clinic.

It is hypothesized that:

• Youth receiving TST will demonstrate a greater decrease in Post-Traumatic Stress Disorder (PTSD) symptoms at the 3, 6, and 9-month follow-up assessments compared to youth receiving treatment as usual (TAU) in the community.
• Youth receiving TST will demonstrate a greater decrease in symptoms of depression, anxiety and problem behaviors (aggression, violence, self-destructive behaviors, etc.) at the 3-, 6- and 9-month follow-up assessments compared to youth receiving TAU.
• Youth receiving TST will have fewer acute mental health service events, such as psychiatric hospitalizations and ED visits compared to youth receiving TAU.
• Greater fidelity to the TST model is associated with better treatment outcomes among youth receiving TST.

Inclusion Criteria:

• Between the ages of 7 and 17.
• Have experienced a trauma and have symptoms of that trauma for more than 1 month
• Have a legal guardian who is willing to give consent and a primary caregiver who will be available for assessments.

Exclusion Criteria:

• Reside outside the study area
• Currently participating in another study
• Do not speak English
• Receive psychotherapy elsewhere
• Have a sibling already participating in the study
• Are acutely suicidal or homicidal
• Demonstrate they are in immediate danger
• Legal guardian does not give consent
• If the primary caregiver does not speak English, does not have consistent access to a telephone, does not have the capacity to answer questions, the child will be excluded.
• If a potential subject has started, stopped, or changed a psychotropic medication within 2 weeks of their intake appointment. If the family is willing to wait for 2 weeks the participant may then be eligible.