Cognitive behavioral therapy (CBT) is a form of psychotherapy that aims to change patterns of thinking or behavior that causes people emotional difficulties. CBT is based on the philosophy that thoughts and perceptions influence behavior. CBT has been proven to be effective for problems such as depression, anxiety, alcohol and drug use, eating disorders such as bulimia, severe mental illness and phobias. CBT is usually a short-term treatment, generally between 6 to 20 sessions. It is appropriate for all ages; children, adolescents and adults. A number of CBT approaches exist. These include Cognitive Therapy, which is based on identifying and changing inaccurate or distorted thinking patterns, emotional responses, and behaviors. Dialectical Behavior Therapy (DBT) addresses thoughts and behaviors while incorporating strategies such as emotional regulation and mindfulness. Multimodal Therapy believes that psychological issues must be treated by addressing seven interconnected modalities: behavior, affect, sensation, imagery, cognition, interpersonal factors, and drug/biological considerations. Rational Emotive Behavior Therapy (REBT) involves identifying irrational beliefs, actively challenging these beliefs, and finally learning to recognize and change these thought patterns. People develop emotional difficulties due to the meanings people give to events in their lives. While undergoing CBT, the individual tells the therapist what causes their anxiety, while the therapist aims to help the person to address rational concerns practically and challenge irrational beliefs.