In 1940, "The Journal of Psychology" defined euphoria as a "state of general well being ... and pleasantly toned feeling." A decade later, finding "ordinary feelings of well being" difficult to evaluate, American addiction researcher Harris Isbell redefined euphoria as behavioral changes and objective signs typical of morphine. •  • </ref> However, in 1957 British pharmacologist D. A. Cahal did not regard opioid euphoria as medically undesirable but an effect which "enhance the value of a major analgesic." The 1977 edition of "A Concise Encyclopaedia of Psychiatry" called euphoria "a mood of contentment and well-being," with pathologic associations when used in a psychiatric context. As a sign of cerebral disease, it was described as bland and out of context, representing an inability to experience negative emotion.