Behaviour therapy with identical twins

Among the patients treated by the writer during the past five years were two pairs of identical twins. Each respective pair of twins suffered from similar neurotic disabilities. While the patients undergoing behaviour therapy either recovered completely or improved substantially, their untreated twin siblings retained their maladaptive habits until they too underwent a course of behaviour therapy. A fifth patient, also one of an identical twin, derived benefit from therapy while his twin brother, opposed to therapeutic intervention on religious grounds, has remained neurotically incapacitated. These eases are followed by comments drawing didactic inferences. Emphasis is placed on the fact that behaviour therapy does not ignore the complex causality of neurotic disturbances. Interpersonal considerations at both causal and remedial levels are discussed.