Obsessive compulsive disorder (OCD) may be suspected based on symptoms of the condition such as obsessive thinking patterns, anxiety and compulsive behavior that relieves this anxiety.

Diagnosis and timely treatment can reduce the impact of this condition on a person’s day-to-day living. People often do not visit a doctor if they suspect they have OCD, because they feel ashamed or embarrassed.

They may also conceal signs of their disorder from friends and family. However, OCD is a long-term health condition that requires medical attention, just as any other illness does.

In order to confirm a diagnosis of OCD, a doctor usually takes the following steps:

Initial screening

The patient is usually asked a series of questions from the Fineberg-Zohar screening questionnaire, which helps determine how likely it is that they have OCD. Examples of the types of questions that may be asked include:

• Do you check things many times?
• Do you wash or clean things many times?
• Do you find things need to be put in a special order or does untidiness upset you?
• Do you take a long time to finish daily activities?
• Are you bothered by thoughts, concerns or fears that you cannot get rid of?

Assessment for OCD

The diagnostic criteria for OCD from the two main international classification systems, ICD-10 and DSM-IV (Diagnostic and Statistical Manual of Mental disorders - IV) are similar. Both sets of criteria state that for OCD to be diagnosed, the following features of the disease must be present:If screening suggests a person may have OCD, the severity of their symptoms are tested, either by the GP or a mental health expert. This involves further questioning which is aimed at finding out how much of the patient’s life is taken up with obsessive thoughts and compulsive behaviors. People are encouraged to be honest throughout this questioning in order for the condition to be accurately diagnosed and the most appropriate treatment course chosen.

• The patient must be experiencing at least one obsession or compulsion that is excessive or unreasonable.
• The obsessions and/or compulsions must cause marked distress.
• The patient must be aware of the irrationality of his or her thoughts and compulsive actions. This is a key feature of OCD.

Assessment of OCD severity

The severity of OCD is determined according to how much the condition is impacting on the patient’s day-to-day living. Disruption to a person’s daily function is referred to as functional impairment and can be divided into the following degrees of severity:

• Severe functional impairment – The obsessive thoughts and compulsive behaviour occupy more than three hours of the patient’s day
• Moderate functional impairment - The thoughts and behaviour occupy one to three hours a day
• Mild functional impairment - The thoughts and behaviour occupy less than one hour a day