An obsession is a persistent preoccupation with something, typically an idea or a feeling. It is a state of being obsessed with recurrent,persistent ideas,thoughts,images or impulses emerge from the unconscious mind.Forced preoccupation with thoughts about a particular topic,associated with brooding,doubting,and inconclusive speculation that occur involuntarily.It comprises an elaborate series of mental acts and the subject feels compelled to complete.Termination depends on proper performance. Compulsion is a psychological state, in which, an individual acts against one’s own will or conscious inclinations.It is compulsive, in that, having a tendency or the power to compel, gets or brings about by force or obtain by pressure and is caused by an obsession. Compulsiveness, the trait of repetitiveness of behaviour often inappropriate, consists characteristic of rigidity and lack of flexibility in behaving. For example, an individual who is excessively orderly, rigid, and pedantic. Many historical figures have shown an obsessive-compulsive adherence to their goals.For instance, Columbus persisted for 18 years to finance his expedition to “India” and Darwin assembled evidence for 22 years prior to present “theory of evolution”. Quite often, the extraordinary concern with self-imposed regularity and control in the pre-obsessive-compulsive individual takes the form of exaggerated perfectionism or concerns that one’s actions may lead to terrible consequences. An obsessive-compulsive neurosis is the outcome of maladaptation or a personality characterized by feelings of inadequacy and insecurity; rigid conscience development; a tendency towards feelings of guilt; and high vulnerability to threat. It occurs due in course to the autonomic motive states including sociocultural factors, psychological as well as biological anomalies.General causes and prognosis: it results because of fear, suspicion, fixed or false idea due to the environmental stimuli, agency of social transmission, or illusion-delusion-hallucinations.