Unlike many diseases, such as cancer or type 2 diabetes, mental illnesses, such as OCD, can’t be diagnosed using a blood test, biopsy, x-ray or physical examination.
Health professionals, such as family doctors, psychiatrists and psychologists, rely on clinical experience and extensive training to determine whether someone meets diagnostic criteria for OCD.
Diagnostic criteria outline symptoms, such as obsessions and compulsions, that most experts agree are strongly associated with OCD and must be present to make a diagnosis. The diagnostic criteria for OCD and other mental illnesses are summarized in a reference book called the "Diagnostic and Statistical Manual of Mental Disorders" (DSM), which is published by the American Psychiatric Association. Physicians and psychologists will often consult the DSM when making a diagnosis.
In addition, your doctor or psychologist may use a structured clinical interview, which contains standardized questions about the nature, duration and impact of the symptoms you are experiencing.
It is important to make sure that your symptoms are consistent with OCD and not another mental illness, so that you get the kind of help you need.
