What is psychotic depression?
Some people who have severe clinical depression (sometimes called major depressive disorder) experience hallucinations and delusions. They are said to have psychotic depression.
People who have severe clinical depression are in a depressed mood most of the day, practically every day, and can lose interest in almost everything.
Mental health professionals call this sort of depression ‘unipolar’ depression in contrast to ‘bipolar disorder’, when people experience both episodes of depression and episodes of mania.
Other symptoms of severe clinical depression include extreme tiredness, disturbed sleep patterns and changes in appetite. People feel worthless and guilty, they are unable to concentrate and are indecisive. Many people also become very anxious, pre-occupied, or overly concerned about their health. When people are severely clinically depressed, their daily life becomes extremely difficult.
The delusions and hallucinations experienced by people with psychotic depression almost always reflect their deeply depressed mood. The delusions and hallucinations are very negative, self-critical, self-punishing and self-blaming, and can make people feel even more anxious.
People with psychotic depression may also experience ‘psychomotor agitation’ – an inability to relax or sit still. They may rock, fidget, or move their legs a lot, for example. Being acutely and severely anxious, often as a result of the symptoms of psychosis, contributes to the psychomotor disturbance.
Unipolar depression tends to be episodic, and studies have shown that the majority of people who have had a first episode of severe clinical depression will go on to have at least one more. After a second and third episode, the risk of relapse increases substantially.
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Who gets psychotic depression?
The estimated numbers of people who are likely to experience severe clinical depression at some time in their lives vary between three and 11 people in every 100. Women are twice as likely than men to develop depression – so two-thirds of people who have severe clinical depression will be women.
Not everyone who has severe clinical depression will experience the symptoms of psychosis. An estimated 10 to 15 per cent of people diagnosed with severe unipolar depression will at some stage go on to develop the symptoms of psychosis.
Researchers do not know why some people do, and others don’t develop hallucinations and delusions. They are therefore unable to predict which people who have unipolar depression will experience the symptoms of psychosis.
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Diagnosis
The classification systems used by mental health professionals to make a diagnosis describe ‘psychotic depression’ as a sub-type of major depressive disorder.
Doctors therefore use the criteria for ‘major depressive disorder’ or ‘severe depressive episode’ with additional symptoms of hallucinations and delusions.
Mental health professionals will make a diagnosis by asking in detail about the symptoms people may be experiencing. They will also find out about an individual’s past experience of depression, and whether family members have ever experienced depression or psychotic depression.
It may, however, be difficult to make a diagnosis. The symptoms of psychosis may be subtle, and people with depression may sometimes not report that they are experiencing hallucinations and delusions because they are embarrassed by them. There is a danger too of misdiagnosis – If people are experiencing psychomotor agitation, for example, their symptoms could be attributed to severe anxiety.
It is important for mental health professionals to work out if people are experiencing the symptoms of psychosis as part of unipolar depression, or as part of bipolar disorder (see Bipolar disorder page). This is because there are different treatments for psychotic depression and bipolar disorder.
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What causes psychotic depression?
Researchers don’t know why some people who have unipolar depression develop the symptoms of psychosis, but they think genes may have a part to play.
Research studies have shown that unipolar depression, particularly severe depression, runs in families. People are much more likely to develop depression if they have a first degree relative (mother, father or sibling) who has experienced unipolar depression. Researchers have also found that people are more likely to develop depression if they have experienced adversity in childhood.
They have identified genes that make people more likely to develop depression, and they have identified genes that play some sort of a role in the symptoms of psychosis. Some researchers think it may be that a person who inherits a combination of these genes may be more likely to develop psychotic depression. However, they do not yet understand how many genes are involved and how they interplay. One theory is that there is a set of genes that contribute to the development of psychosis, and some individual genes that determine whether people go on to develop bipolar disorder, schizophrenia or unipolar depression.
Researchers also think high levels of the stress hormone cortisol may be involved in some way. High cortisol levels are found in people with depression and people with other mental health problems.
Some researchers think that the content of hallucinations, particularly voices, experienced by people with psychotic depression may be associated with traumatic events in the recent or distant past.
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How is psychotic depression treated?
People who have severe, clinical depression and experience hallucinations and delusions should be referred to a specialist mental health service. Some people may need hospital treatment: there are not many specialist units in the country, so this may be on a general psychiatric ward. Alternatively, they may be under the care of a community-based home treatment team.
The treatment will initially concentrate on the depression, rather than the symptoms of psychosis. People will normally already be taking medication for severe depression – antidepressants, or a combination of drugs, which may include antidepressants, mood stabilisers and drugs that counter anxiety (anxiolytics). The National Institute for Health and Care Excellence (NICE) recommends that in addition to medication, psychological therapies should be part of a package of treatment for severe clinical depression.
When delusions and hallucinations develop, mental health professionals may also prescribe an antipsychotic drug. However, there hasn’t been much research into what is the best combination of medication for psychotic depression.
The NICE guidance on the treatment and management of depression in adults says mental health professionals should consider prescribing antipsychotic medication, though it also acknowledges there is not much evidence available about the best type or dose.
Psychotic depression is one of the few illnesses where ECT (electroconvulsive therapy) may still be used as a treatment. The NICE guidance on depression says ECT should be used to treat the symptoms of profound depression, not the symptoms of psychosis, and should only be used if urgent treatment is needed, or if other treatments have not helped the depression. ECT (when an electric current is passed through the brain) is always given in hospital, and under general anaesthetic. Health professionals should explain how ECT works, and the potential side effects – people may experience a loss of memory, for example. People have to give their consent before ECT is administered.
Other treatments for severe clinical depression are currently being developed and tested. These include rTMS – repetitive transcranial magnetic stimulation. This involves putting an electromagnet on the scalp to produce magnetic pulses that stimulate a small part of the brain to reduce its activity. People are conscious throughout the procedure and no anaesthetic is needed. NICE does not recommend rTMS for the treatment of depression because there is not yet sufficient evidence to prove it is effective.
Other researchers are trialling drugs that may reduce cortisol levels, and some studies are looking at the effectiveness of ‘vagus nerve stimulation’, where an electrode is placed in the brain to constantly stimulate and regulate electrical activity.