Before discussing the similarities between classical and operant conditioning, it's important to understand each concept individually. According to Gerald Corey's "Theory and Practice of Counseling and Psychotherapy," "classical conditioning (respondent conditioning) refers to what happens prior to learning that creates a response through pairing." A famous example of this is Ivan Pavlov's experiment with dogs. When dogs heard a bell sound when they were being fed, the dogs eventually salivated just by hearing the bell. However, if the bell was rung repeatedly but no food was presented, the dogs would eventually stop salivating when they heard the bell. Classical conditioning is famous for its use of systemic desensitization.
According to Gerald's Corey's "Theory and Practice of Counseling and Psychotherapy," operant conditioning "involves a type of learning in which behaviors are influenced mainly by the consequences that follow them." This means that if individuals receive some kind of positive reinforcement for their behaviors, they will continue those behaviors; but if they receive negative or no reinforcement for their behaviors, they will eventually stop those behaviors. Operant conditioning stipulates that learning can only occur in conjunction with positive and negative reinforcement and positive punishment and negative punishment.
Both classical and operant conditioning are psychological theories that originated in the field of behavior therapy, a precursor to modern-day cognitive behavior therapy. Both classical and operant conditioning are non-insight-based therapies, which means that insight, or awareness, is not a requirement for change as it is in other psychological approaches such as psychoanalytic therapy and existential therapy. Basically, classical and operant conditioning stipulate that behaviors can be changed without delving into the cause of the behavior, the past or the subconscious.
In practice, both classical and operant conditioning are primarily used to treat phobias. However, according to Corey Gerald in "Theory and Practice of Counseling and Psychotherapy," both classical and operant conditioning have also been used to treat nightmares, obsessions, depression, compulsions, anorexia and anxiety. The classical conditioning technique of desensitization has been empirically tested and is one of the most widely used treatment techniques in psychology today. Both techniques are mainly used by cognitive behavior therapists, as pure behavior therapy is rarely used in clinical practice anymore.