The theory of unpleasant symptoms posits that symptoms experienced by patients can be measured along four dimensions: time, intensity, quality, and distress. Physiological, psychological, and situational factors can influence a patient's experience of symptoms. Symptoms may cause changes in a patient's functional and cognitive responses. It is important for nurses to evaluate a patient's symptoms holistically and identify any contributing physiological or lifestyle factors. Properly documenting a patient's symptoms over time can help determine the effectiveness of treatment plans.