For many years, mental health professionals thought of OCD as a rare disease because only a small minority of their patients had the condition. The disorder often went unrecognized because many of those afflicted with OCD, on efforts to keep their repetitive thoughts and behaviours secret, failed to seek treatment. This led to underestimates of the number with the illness. However, a survey conducted in the early 1980s by the National Institute of Mental Health (NIMH) in the USA provided new knowledge about the prevalence of OCD. The NIMH survey showed that OCD is more common than such severe mental illnesses as schizophrenia, bipolar disorder, or panic disorder. An Edmonton study (1988) showed that OCD affects 3% or people in a lifetime. 600,000 Canadians are likely to be suffering from OCD. OCD strikes people of all ethnic groups. Males and female are equally affected. The social and economic costs of OCD were estimated to be $8.4 billion in 1990 in the USA (DuPont er al, 1994).
Although OCD symptoms typically begin during the teenage years or early childhood, recent research shows that some children develop the illness at earlier ages, even during the preschool years. Suffering from OCD during the early stages of a child's development can cause severe problems for the child. It is important that the child receive evaluation and treatment by a knowledgeable clinician to prevent the child from missing important opportunities because of this disorder.