Treatment of mental illness in Black and minority ethnic groups differs from that in the majority. ¹ Large differences in admission, seclusion and detention rates have been measured for different ethnicities - particularly when data from Black and White patients are compared. Specifically, Black patients are almost four times more likely to be detained under the Mental Health Act, ^{Reference Singh, Greenwood, White and Churchill2} up to nine times more likely to be admitted into hospital. ³ Black people also have a longer length of admission ³ and are almost eight times more likely to be treated on a high-security ward. ^{Reference Leese, Thornicroft, Shaw, Thomas, Mohan and Harty4} These differences have complex, often multifactorial causes and have been attributed to misdiagnosis, delays in seeking and receiving treatment, higher incidences of, and exposure to, risk factors for psychosis, ^{Reference Kirkbride, Fearon, Morgan, Dazzan, Morgan and Tarrasch5} and discrimination. Despite the Department of Health's numerous recommendations in its Delivering Race Equality ¹ and Inside Outside ⁶ reports, these differences continue to exist and, accepting the inherent limitations of data collected from a cross-sectional survey, are not improving. ³ Ultimately, these findings have led to accusations, vociferously rejected by many, ^{Reference Singh and Burns7-Reference Singh9} of institutional racism in mental health services. ^{Reference Murray and Feron10}

Race and physical healthcare

Differences in the provision of health services to Black and minority ethnic groups can also extend into physical healthcare. ⁶ Access to treatment may be affected by ethnicity, particularly in the USA but also within the equitable UK healthcare system. Examples of UK healthcare inequality include reduced cervical cancer screening and reduced rates of coronary angioplasty in South Asian populations. ^{Reference McKenzie and Bhui11,Reference Acheson12} There are numerous well-documented differences in the medical treatment of Black and minority ethnic patients in the USA, particularly for Black compared with White patients, even after accounting for medical insurance status. Examples include poorer outcome and treatment of colorectal cancer ^{Reference Feder, Crook, Magee, Banerjee, Timmis and Hemingway13} and less frequent use of newer drugs for ischaemic stroke. ^{Reference Ball and Elixhauser14}

Race and metabolism of psychotropics

Prescribing in psychiatry differs by race for a variety of reasons, not least because genetic variation can affect the metabolism of psychotropics. Many psychotropics are metabolised by the hepatic cytochrome P450 (CYP450) enzymes - a family of enzymes initially developed by animals over billions of years to detoxify plant toxins. This enzymatic system includes over 40 different enzymes but only 6 are responsible for almost all drug metabolism. Some of these enzymes are subject to genetic polymorphism and Black and minority ethnic groups have variants of these isoenzymes with different, often slower, activity. Specifically, CYP2D6, CYP2C9 and CYP2C19, enzymes that are important in metabolising numerous antidepressants, antipsychotics and benzodiazepines, can be polymorphic. This means that some populations may metabolise psychotropics more slowly than others resulting in higher plasma levels. Determining the effects of genetic polymorphism on CYP450 enzymes is difficult, as even interethnic differences can be marked - in Black individuals, poor metabolism of CYP2D6 occurs in 1.8% of Ethiopians compared with 19% of South Africans. ^{Reference Johnston, Fung, Gillum, Smith, Brass and Lichtman15} Overall, there are probably fewer people with poor metabolism of CYP2D6 and CYP2C9 in Asian and Black populations than in White populations, ^{Reference Bernard, Neville, Nguyen and Flockhart16} and a greater proportion of East Asians than Black and White people with poor metabolism of CYP2C19. ^{Reference Baxter17,Reference Oesterheld, Wynn, Oesterheld, Cozza and Armstrong18} Ultra-extensive and intermediate metabolisers also exist and proportions of these also vary by ethnicity: for instance, over 50% of Asian people have intermediate metabolism of CYP2D6. ^{Reference Johnston, Fung, Gillum, Smith, Brass and Lichtman15} Although one would expect that genetic polymorphism of CYP450 enzymes would have an important effect on dosing of psychotropics for Asians, it does not explain differences in prescribing between other ethnic groups. That is not to say that metabolising ability has no effect on dosing or adverse effects of medication (indeed, those with poor metabolism of CYP2D6 have a greater risk of developing tardive dyskinesia and experiencing extrapyramidal side-effects ^{Reference Baxter17} ), but that an individual's own metabolising ability may be more important than their ethnicity alone. Currently in the UK, determining CYP450 polymorphisms is prohibitively expensive and is usually only possible within a clinical trial.

Race and psychotropic prescribing

Are there differences in prescribing of psychotropics in Black and minority ethnic groups that relate to prejudice rather than metabolism? Patients and carers seem to think so, ^{6,Reference Oesterheld, Wynn, Oesterheld, Cozza and Armstrong19} and, after the inquiry into the death of David Bennett, ²⁰ the issue needed investigation. ¹

Most of the studies examining psychotropic use by ethnicity have been completed in the USA. Differences in antipsychotic treatment by ethnicity include: an increased likelihood of receiving an antipsychotic, ^{Reference Sallah, Sashidharan, Stone, Struthers and Blofeld21-Reference Flaskerud and Hu23} higher doses, ^{Reference Szarek and Goethe24-Reference Delbello, Soutullo and Strakowski26} older drugs ^{Reference Diaz and de Leon27,Reference Segal, Bola and Watson28} and more frequent use of depot formulations. ^{Reference Walkup, McAlpine, Olfson, Labay, Boyer and Hansell29} Again, these differences are pronounced for Black compared with White patients. These studies analysed mostly large US databases and adjusted for only a few confounding factors affecting the prescribing of antipsychotics; many did not adjust for health insurance status. The healthcare systems of the UK and the USA differ markedly and have a profound effect on access to, and receipt of, treatment.

There are few UK studies examining ethnicity and antipsychotic use. One survey ^{Reference Fleck, Hendricks, Delbello and Strakowski30} found no significant differences (after adjustment for five confounding variables) in doses of antipsychotics taken by Black and White patients. However, Black patients were more likely than White patients to be receiving a depot antipsychotic and at a significantly higher dose. Our cross-sectional surveys of antipsychotic prescribing quality and ethnicity have included large numbers of patients from three NHS trusts and accounted for multiple confounding factors. ^{Reference Daumit, Crum, Guallar, Powe, Primm and Steinwachs31,Reference Kuno and Rothbard32} We found no significant differences between Black and White patients for antipsychotic dose, high dose (>100% of maximum dose) or type (typical or atypical) prescribed, even after adjustment for over 20 different confounding factors. However, both higher costs of antipsychotic medication and polypharmacy (>1 antipsychotic prescribed) were significantly more likely in Black patients. ^{Reference Daumit, Crum, Guallar, Powe, Primm and Steinwachs31}

Antidepressant treatment may also vary by ethnicity. Black and Asian patients, especially those living in areas of high ethnic density, are less likely than White patients to access care for depression ^{Reference Lloyd and Moodley33} and to be prescribed an antidepressant. ^{Reference Connolly, Rogers and Taylor34,Reference Connolly and Taylor35} Moreover, even in vascular disease, where depression is associated with higher mortality, rates of antidepressant use are much lower in Black compared with White patients even after adjustment for depression severity. ^{Reference Alegria, Chatterji, Wells, Cao, Chen and Takeuchi36} On the other hand, a study of psychiatrists' assessments of video vignettes of late-life depression in individuals who differed by gender and race (African American or White) found no differences in diagnosis or treatment. ^{Reference Gonzalez, Croghan, West, Williams, Nesse and Tarraf37} This suggests that factors other than bias by race are also important. Racial differences in acceptability ^{Reference Walters, Ashworth and Tylee38} of use of antidepressants have been cited as a potential cause of these findings. However, antidepressant stigma appears to be greater in White compared with Black patients. ^{Reference Waldman, Blumenthal, Babyak, Sherwood, Sketch and Davidson39}

Conclusions

It is clear that there is quite some way to go before UK health services provide equal treatment to all minority ethnic groups. However, prescribing of antipsychotics appears overall to be broadly equitable in minority ethnic groups. Further investigation of the potentially complex and numerous reasons for these differences is urgently needed.