Dopamine presence linked to early psychosis
07 January 2009
A new study shows for the first time that people who may be at risk of schizophrenia show increased levels of the brain chemical messenger Dopamine. The paper is published on line this month in the journal the Archives of General Psychiatry.
Dr Oliver Howes and colleagues at the Medical Research Council Clinical Sciences Centre, Hammersmith Hospital and Institute of Psychiatry, King’s College London used a brain scanning technique to measure levels of dopamine in people attending the Outreach and Support in South London (OASIS) clinic. This specialist clinic, headed up by Professor Philip McGuire also of the Institute of Psychiatry at King’s, is for people who show possible early signs of schizophrenia.
The researchers compared the brain dopamine levels in those patients attending the OASIS clinic to levels in people already diagnosed with schizophrenia, and volunteers free of such problems. Dopamine levels were elevated in the people who may be at risk of schizophrenia, to a degree approaching that seen in the patients with schizophrenia. The researchers also found that higher levels of dopamine were linked to more severe symptoms, and to worse performance on thinking tests.
Dr Howes, Senior Clinical Lecturer at the MRC-Clinical Sciences Centre and Institute of Psychiatry, King’s said 'Schizophrenia is one of the top ten health problems in young adults worldwide. Current treatments are helpful but we desperately need better ones.
'The holy grail of research is to find a way of preventing this devastating illness before it starts. Our finding that dopamine levels are high in people showing very early signs of developing schizophrenia gives an important clue as to what is causing schizophrenia and other psychotic illnesses.
'If the results are confirmed, future treatments could target this part of the brain’s dopamine system to prevent the full development of the illness. As roughly 1 in 10 people with schizophrenia die from suicide, predominantly in the first few years after the illness starts, a treatment that prevents the full illness could save many lives as well as alleviating suffering. The scans, in conjunction with previous work by us and others, also indicated that the problem is specific to a particular part of the dopamine system. This suggests that all current drugs are acting in the wrong place to address the primary problem - designing drugs to reverse the primary problem could offer the hope of better treatments for schizophrenia.'
What is schizophrenia?
Schizophrenia is the commonest of the severe mental illnesses, and interferes with the sufferers’ thoughts, feelings, and ability to plan and carryout actions. It can diminish motivation, initiative, mood and emotional expression. This may lead sufferers to become slower to talk and act, and increasingly indifferent to social contact and emotional interaction. Over time patients may lose contact with their friends and family, be unable to continue working, and become withdrawn and isolated.
Just fewer than one in a hundred people will suffer from schizophrenia at some point in their life. It is more common in those living in urban than rural areas, and in some migrant groups, such as African-Caribbean people living in the UK. It is an illness that affects adults, being rare in children and gradually more common during adolescence.
Schizophrenia is a complex and variable condition, and treatment often requires sustained input from a multi-disciplinary care team involving psychiatrists, nurses, social workers, occupational therapists and psychologists. Although there is no ‘cure’ for schizophrenia, the rapidly increasing understanding of the psychological and neurobiological aspects of the illness is now feeding through into better treatments and an improved outlook.
The papers authors are: Oliver D. Howes, MRCPsych, DM; Andrew J. Montgomery, MRCPsych, PhD; Marie-Claude Asselin, PhD; Robin M. Murray, FRCPsych, DSc; Isabel Valli, MBBS; Paul Tabraham, PhD; Elvira Bramon-Bosch, MRCPsych, PhD; Lucia Valmaggia, PhD; Louise Johns, PhD; Matthew Broome, MRCPsych; Philip K. McGuire, FRCPsych, PhD, Paul M. Grasby, MRCPsych, MD.
For a copy of the full paper Elevated Striatal Dopamine Function Linked to Prodromal Signs of Schizophrenia please go to the following link: http://archpsyc.ama-assn.org/cgi/content/short/66/1/13 or refer directly to the journal The Archives of General Psychiatry, 2009;66(1):13-20.