Depersonalisation-derealisation disorder: symptoms, causes and treatment in the UK

The NHS explains that dissociation is a way the mind copes with too much stress. Depersonalisation-derealisation disorder is one form. In depersonalisation you feel as if you are outside yourself, watching your own actions, feelings or thoughts from a distance. In derealisation you feel that the world around you is unreal: the NHS says people and things may seem lifeless or foggy. You can have depersonalisation, derealisation or both together.

South London and Maudsley NHS Foundation Trust gives the same description and adds that periods of dissociation can last for a relatively short time (hours or days) or much longer (weeks or months). The NHS adds that the experience may last only a few moments or come and go over many years.

The NHS lists feeling disconnected from yourself and the world around you as a key symptom of dissociative disorders. A research protocol from University College London describes experiences of unreality, detachment or being an outside observer with respect to your thoughts, feelings, sensations, body or actions, such as perceptual alterations, a distorted sense of time, an unreal or absent self, and emotional or physical numbing. For derealisation it describes people or objects experienced as unreal, dreamlike, foggy, lifeless or visually distorted.

The NHS notes that someone with a dissociative disorder may also have post-traumatic stress disorder, depression, anxiety and panic attacks, an eating disorder, OCD or sleep problems.

• Feeling detached from your body, thoughts or emotions, as if watching yourself.

• The world seeming unreal, dreamlike, foggy or lifeless.

• Emotional or physical numbing.

• A distorted sense of time or visual distortions.

• Other mental health symptoms alongside, such as anxiety, depression or panic, which the NHS says can accompany dissociative disorders.

The NHS says there are many possible causes of dissociative disorders, including previous traumatic experience. Many people with a dissociative disorder have had a traumatic event during childhood, and some dissociate after experiencing war, kidnapping or an invasive medical procedure. It describes switching off from reality as a normal defence mechanism that helps a person cope during a traumatic time, and says it becomes a problem when the person continues to act as though the environment is still threatening.

South London and Maudsley adds that the causes are not well understood and may relate to previous trauma or to a tendency to develop physical rather than psychological symptoms when distressed. The assessment includes a physical check for things such as head injury or drug or alcohol misuse that can produce similar symptoms.

The NHS says a GP may examine you and do some tests to check if another illness might be the cause of your symptoms, and may refer you to a mental health specialist for a full assessment. The specialist should have a good understanding of dissociative disorders. South London and Maudsley says assessment may include a physical examination to rule out things like head injury or drug or alcohol misuse, and questions about thoughts, feelings, behaviour and symptoms. Both stress the importance of being honest and not feeling ashamed.

The UK research protocol says the condition is chronically under-diagnosed, with diagnosis often coming after delays of several years, and that the prevalence among people using mental health services is higher, at approximately 20%, usually together with other disorders.

The NHS says talking therapies such as counselling or psychotherapy are often recommended, with the aim of helping you cope with the underlying cause of your symptoms and to learn and practise techniques to manage periods of feeling disconnected. It says EMDR is sometimes used, and that there is no specific medicine to treat dissociation, though antidepressants may be prescribed for associated depression, anxiety or panic.

The UK research protocol is candid about the evidence. It says there is currently no NICE guidance on treatments for the condition and that, in systematic reviews, the strongest evidence is for CBT adapted for the condition, with little benefit shown from a variety of medicines and other therapies. Uncontrolled studies from a specialist clinic reported symptom reductions, and a feasibility trial in NHS services (12 to 24 CBT sessions over 6 months) is testing it further. It stresses that the data cannot yet prove how well CBT works.

The NHS describes dissociation as a way the mind copes with too much stress, and suggests talking to your partner, family and friends about your experience so they can understand how you feel, and reading about other people with similar experiences. Treating associated anxiety, depression and sleep problems is an important part of care.

Charities such as the Unreal charity, mentioned in the UK research protocol, and Mind provide information and peer support.

The NHS says that if you have thoughts about taking your life it is important to ask someone for help: speak to someone you trust, go to A&E, contact NHS 111 or make an urgent appointment with a GP. If you have seriously harmed yourself, call 999.