Attention biases in threat processing have been assigned a prominent role in the etiology and maintenance of anxiety disorders. Attention Bias Modification Treatment (ABMT) utilizes computer-based protocols to implicitly modify biased attentional patterns in anxious patients. This is a double-blind randomized controlled trial of ABMT for clinically anxious 10-18 year-olds. Participants will be assessed using clinical interviews and parent- and self-rated questionnaires before, in the middle and after twelve sessions of ABMT or control groups, and again at ten-week follow-up. Outcome measures will be anxiety symptoms and depression as measured by gold standard questionnaires as well as structured clinical interviews with youth and their parents. Attentional threat bias, Attentional control and interpretation of ambiguous information will also be measured to explore potential mediators of ABMT's effect on anxiety. The investigators expect the findings to inform pathways to treatments for anxious children and to provide initial information on mechanisms of ABMT efficacy.

Inclusion Criteria:

• Primary diagnosis of GAD, SOP, or SAD.
• Co-morbid attention deficit hyperactivity disorder (ADHD) or depressive disorders must be treated with medication and stable.
• Tics or impulse control problems must be treated with medication, stable and cause minimal or no impairment.

Exclusion Criteria: To be excluded youth must:

• meet diagnostic criteria for Organic Mental Disorders, Psychotic Disorders, Pervasive Developmental Disorders, or Mental Retardation.
• show high likelihood of hurting themselves or others.
• have not been living with a primary caregiver who is legally able to give consent for the child's participation.
• be a victim of previously undisclosed abuse requiring investigation or ongoing supervision.
• be involved currently in another psycho-social treatment.
• have a serious vision problem that is not corrected with prescription lenses.
• have a physical disability that interferes with their ability to click a mouse button rapidly and repeatedly.