Formal diagnosis may be performed by a psychologist, psychiatrist, clinical social worker, or other licensed mental health professional. To be diagnosed with OCD, a person must have obsessions, compulsions, or both, according to the Diagnostic and Statistical Manual of Mental Disorders (DSM). The Quick Reference to the 2000 edition of the DSM states that several features characterize clinically significant obsessions and compulsions, and that such obsessions are recurrent and persistent thoughts, impulses, or images that are experienced as intrusive and that cause marked anxiety or distress. These thoughts, impulses, or images are of a degree or type that lies outside the normal range of worries about conventional problems. A person may attempt to ignore or suppress such obsessions, or to neutralize them with some other thought or action, and will tend to recognize the obsessions as idiosyncratic or irrational. Compulsions become clinically significant when a person feels driven to perform them in response to an obsession, or according to rules that must be applied rigidly, and when the person consequently feels or causes significant distress. Therefore, while many people who do not suffer from OCD may perform actions often associated with OCD (such as ordering items in a pantry by height), the distinction with clinically significant OCD lies in the fact that the person who suffers from OCD must perform these actions to avoid significant psychological distress. These behaviors or mental acts are aimed at preventing or reducing distress or preventing some dreaded event or situation; however, these activities are not logically or practically connected to the issue, or they are excessive. In addition, at some point during the course of the disorder, the individual must realize that his or her obsessions or compulsions are unreasonable or excessive. Moreover, the obsessions or compulsions must be time-consuming (taking up more than one hour per day) or cause impairment in social, occupational or scholastic functioning. It is helpful to quantify the severity of symptoms and impairment before and during treatment for OCD. In addition to the person's estimate of the time spent each day harboring<unk> -compulsive thoughts or behaviors, concrete tools can be used to gauge the person's condition. This may be done with rating scales, such as the Yale–Brown<unk>  Compulsive Scale (Y-BOCS; expert rating) or the<unk> -compulsive inventory (OCI-R; self-rating). With measurements such as these, psychiatric consultation can be more appropriately determined because it has been standardized. OCD is sometimes placed in a group of disorders called the<unk><unk> compulsive spectrum. Differential diagnosis OCD is often confused with the separate condition<unk><unk> compulsive personality disorder (OCPD). OCD is egodystonic, meaning that the disorder is incompatible with the sufferer's self-concept. Because egodystonic disorders go against a person's self-concept, they tend to cause much distress. OCPD, on the other hand, is egosyntonic, marked by the person's acceptance that the characteristics and behaviors displayed as a result are compatible with their self-image, or are otherwise appropriate, correct, or reasonable. As a result, people with OCD are often aware that their behavior is not rational and are unhappy about their obsessions but nevertheless feel compelled by them. By contrast, people with OCPD are not aware of anything abnormal; they will readily explain why their actions are rational. It is usually impossible to convince them otherwise, and they tend to derive pleasure from their obsessions or compulsions.
Obsessive–compulsive disorder
Obsessive–compulsive personality disorder
Conduct disorder
Major depressive disorder
Psychopathy
Anxiety disorder
Tourette syndrome
Eating disorder