Negative affectivity (NA), also known as an adverse effect, is a personality trait characterized by negative feelings and low self-esteem. Several negative emotions comprise negative affectivity, including contempt, anger, guilt, disgust, anxiety, and apprehension. Low negative affectivity is marked by regular feelings of peace and serenity and feelings of confidence, engagement, and enormous excitement.

The negative emotional reaction varies in persons. The main personality element of anxiety or neuroticism, which is included within the Big Five personality traits as emotional control, closely corresponds to negative involvement. The Big Five personality traits are generosity, conscientiousness, extraversion, neuroticism, and acceptance. Neuroticism is a personality character that causes extreme mood swings, frequent melancholy, stress, and irritability, and it predicts the formation and beginning of all "typical" mental diseases. Negative affectivity has been linked to various features, including self-reported stress, poor coping abilities, health issues, and the recurrence of unpleasant occurrences. Excess weight and psychiatric problems are common side effects.