Delusional disorder: fixed false beliefs, assessment and support

Psychosis, the NHS explains, is when people lose some contact with reality. It can involve hallucinations, delusions and disordered thinking and speaking. The NHS describes a delusion as a strong belief that is not shared by others.

Rethink Mental Illness lists delusional disorder among the conditions that psychosis can be related to, alongside schizophrenia, bipolar disorder, schizoaffective disorder, drug-induced psychosis, depression with psychotic symptoms, postpartum psychosis, brief psychotic episode and delirium. It describes delusional disorder as having delusions for several months or more, likely to be constant and lifelong beliefs, and unlikely to include hearing voices.

Because the published patient information on delusional disorder specifically is short, much of what follows draws on the general NHS guidance on psychosis. Your clinician can explain how it applies to you.

The NHS lists the three main symptoms of psychosis as hallucinations, delusions and disordered thinking and speaking. In delusional disorder, delusions are the prominent feature.

The NHS gives the example of someone believing there is a conspiracy to harm them. It notes that the combination of hallucinations and delusional thinking can cause severe distress and a change in behaviour. Experiencing the symptoms of psychosis is often referred to as a psychotic episode.

The sources used here give only this general description, so a clinician will ask about the specific beliefs and how they affect your life.

The NHS says you should see a GP immediately if you are experiencing symptoms of psychosis, because it is important that psychosis is treated as soon as possible and early treatment can be more effective. The GP may ask questions to determine the cause and should refer you to a mental health specialist for further assessment and treatment.

If you are concerned about someone else, the NHS says you could contact a GP for them, or their mental health worker if they are already supported by a service. If their symptoms are severe enough to need urgent treatment and could put them at risk, you can take them to the nearest A&E if they agree, call their GP or out-of-hours GP, or call 999 and ask for an ambulance.

Rethink adds that for urgent mental health support you can call NHS 111, and that NHS early intervention in psychosis teams support people experiencing psychosis.

The NHS says that it is sometimes possible to identify the cause of psychosis as a specific mental health condition, such as schizophrenia, bipolar disorder or severe depression. It can also be triggered by a traumatic experience, stress, drug misuse, alcohol-use disorder, side effects of prescribed medicine, a physical condition such as a brain tumour or dementia, a head injury or childbirth.

Because several physical and substance-related causes are possible, a GP or specialist may check for them. Rethink describes delusional disorder as delusions lasting several months or more.

The NHS says treatment for psychosis depends on the cause but usually involves a combination of antipsychotic medicine, which can help relieve symptoms, and talking therapies, with one-to-one CBT and family interventions that may involve partners, family members and close friends, plus social support with needs such as education, employment or accommodation.

Some people are recommended to take antipsychotics on a long-term basis, possibly for the rest of their lives, while others may be able to gradually reduce the dose and stop if there is marked improvement. The NHS says not to stop prescribed medicines suddenly because this could trigger a relapse. If episodes are severe, a person may need to be admitted to a psychiatric hospital for treatment.

The NHS says people with a severe mental illness can have a physical check-up at their GP surgery once a year.

The NHS says people with a history of psychosis are more likely than others to have drug or alcohol misuse problems, and that alcohol or drug use can make psychotic symptoms worse. People with psychosis have a higher than average risk of self-harm and suicide.

If you are feeling suicidal, the NHS says you can call the Samaritans free of charge, go to your nearest A&E and tell staff how you are feeling, contact NHS 111, speak to a friend, family member or someone you trust, or make an urgent appointment with a GP, psychiatrist or care team.

On the NHS, assessment and treatment are through your GP, community mental health teams and, for those eligible, early intervention in psychosis services. Annual physical health checks are available for people with severe mental illness.

Private psychiatric assessment is available for people who want to be seen sooner. Medicines such as antipsychotics are prescribed by a psychiatrist, and it is important to keep your GP informed so that monitoring and physical health checks stay joined up.