Psychology is the scientific study of human behaviour and mental processes. Nursing is a profession that involves not only caring for the physical needs of patients but also understanding their emotions, thoughts, attitudes, personality, behaviour and social relationships. A patient who enters a hospital may experience fear, anxiety, pain, uncertainty, loneliness and dependence on others. Therefore, knowledge of psychology is essential for nurses to provide effective, compassionate and holistic care. Behavioural sciences, including psychology, help nurses understand why people behave in particular ways and how their behaviour can be influenced by physical, psychological, social and environmental factors. Psychology helps nurses understand the patient as a whole person rather than merely as someone suffering from a disease. Patients differ in their personality, intelligence, emotional maturity, beliefs, attitudes, coping abilities and responses to illness. For example, two patients with the same disease may respond very differently. One may remain calm and cooperative, while another may become frightened, irritable or withdrawn. Psychological knowledge enables nurses to recognize these differences and modify their approach according to individual needs. Understanding human behaviour is one of the most important applications of psychology in nursing. A nurse interacts with patients, relatives, doctors, colleagues and other healthcare professionals. Behaviour may be influenced by age, personality, culture, previous experiences, family relationships, stress and illness. By understanding these factors, nurses can interpret patient behaviour more accurately. A patient who refuses treatment may not necessarily be uncooperative; the refusal may result from fear, lack of information, depression or previous unpleasant experiences. Psychological understanding helps the nurse identify the underlying cause and respond appropriately. Psychology is particularly important in establishing effective nurse-patient relationships. A therapeutic relationship is based on trust, respect, empathy, acceptance and effective communication. Nurses spend considerable time with patients, often more than other healthcare professionals. Patients may share personal concerns, fears and emotional difficulties with nurses. Psychological principles help nurses listen attentively, avoid judgment, respect individual differences and communicate in a supportive manner. A