Many studies suggest that the extensive psychiatric needs of some patients could take attention away from management of other health problems and from the usual health promotion services physicians provide. Studies suggest that medical comorbidity has often been under recognized and under diagnosed in psychiatric patients, especially among those with schizophrenia. Unrecognized physical diseases are often associated with serious, potentially fatal illness, and may exacerbate the symptoms of psychiatric illness.

The disorder of schizophrenia has been repeatedly associated with a higher than normal incidence of medical illnesses- specifically, diabetes mellitus (DM). The prevalence of DM in a retrospective study of 95 chronic schizophrenic patients was found to be 15.8% - 4 to 5 times higher than that reported in epidemiological surveys in the general population. This increased risk has recently been formally recognized in the Canadian diabetes practice guidelines. In addition, the first line treatment of schizophrenia as per many published clinical practice algorithms, novel antipsychotics (NAP), has been associated independently with increased risk for diabetes. Novel antipsychotics such as clozapine, olanzapine, quetiapine, and risperidone have demonstrated efficacy in the treatment of schizophrenia with generally fewer extrapyramidal side effects than high dosed typical neuroleptics. However, there is accumulating data suggesting that treatment with at least some of the NAPs may be associated with the development of DM and associated risk factors. The use of olanzapine, for example, has been associated with weight gain, exacerbation of previously well-controlled diabetes, and onset of type 1 and type 2 diabetes. Clozapine has also been associated with weight gain in several reports, as well as increased risk of developing diabetes, and at least one report citing deaths from diabetic ketoacidosis after long-term use.

High-risk groups need targeted diabetes strategies. The Canadian diabetes practice guidelines outline that the service model needed to achieve the benchmarks set for diabetes care will need to be designed to reflect the unique diabetes related challenges faced by various segments of the diabetes epidemic. Diabetes care should be organized around a multidisciplinary diabetes healthcare (DHC) team that can establish and sustain a communication network between the person with DM and the necessary healthcare and community systems. The high risk mental health communities in Ontario need a targeted primary health care service delivery model that attends to the unique set of diabetes related challenges they face, including: weight increase related to medication use, inadequate self-care resources and capacity related to poverty, social constraints and lack of supports, communication barriers and mental health symptomology impacting interactions with service providers.

Current guidelines for diabetes management are clear regarding the monitoring and treatment of identified high-risk groups. Screening for DM should be performed every three years in individuals over 40 years of age. However, more frequent and/or earlier testing with a 75-g Oral Glucose Tolerance Test (OGTT) should be considered in people with identified risk factors such as schizophrenia and NAP use. Annual screening could detect individuals with undiagnosed DM as well as individuals with the pre-diabetic conditions of Impaired Fasting Glucose and Impaired Glucose Tolerance. Results of large, well-designed studies assessing early interventions in adults to prevent the progression from pre-diabetic conditions to DM have recently been published. These studies have demonstrated significant risk reduction with lifestyle management and appropriate pharmacologic interventions. It is also well documented that a comprehensive multidisciplinary Diabetes Healthcare team can help slow the progression of the disease and reduce the incidence of DM-related complications for those already diagnosed with DM.

The London Intercommunity Health Centre (LIHC) has recently piloted a diabetes program addressing the needs of a high-risk mental health population within the recommended guidelines. The program was designed as a "one stop shop" for self-management teaching, medication and glucose monitoring, and referral to specialist providers as needed. The structure of the program followed the Canadian Diabetes Association Clinical Practice Guidelines. Although the program has yet to be implemented long enough to determine if the progression from pre-diabetes to diabetes was prevented, pre-diabetic patients involved in the program have demonstrate clinically significant improvement in lipid profiles and blood pressure measurements. Those patients diagnosed with DM, who participated in the program, were found to attend regularly, and demonstrated a clinically significant improvement in their metabolic control. Thus, initial results from the LIHC, and a recent extension of this model into a community population, indicate that this model of diabetes care for this high-risk mental health population is promising for diabetes risk and disease management.