The three d"s of abnormality: distressing, deviant, dysfuncional. Whether a behaviour is considered abnormal involves a social judgment made on the basis of the three d"s: distress, dysfunction, and deviance. Abnormal behaviour: behaviour that is personally distressful, personally dysfuncional, and/or so culturally deviant that other people judge it to be inappropriate or maladapive. Trephinaion: to release the spirit, a sharp tool was used to chisel a hole about 2 cenimeters in diameter in the skull. * general paresis, a disorder characterized by mental deterioraion and bizarre behaviour, resulted from massive brain deterioraion caused by the sexually transmited disease syphilis. This was a breakthrough the irst demonstraion that a psychological disorder was caused by an underlying physical malady. Vulnerability-stress model: a model that explains behaviour disorders as resuling from predisposing biological or psychological vulnerability factors that are triggered by a stressor - some recent or current event that requires a person to cope.