The link between schizophrenia and diabetes
Current Psychiatry. 2012 October;11(10):28-46
October 1, 2012|Current Psychiatry
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Vigilant metabolic monitoring informs treatment decisions
Patients should actively participate in treatment that involves learning about the illness, making lifestyle changes, working on self-care, and keeping regular medical appointments. Three components of lifestyle change must be addressed:
- Diet: counseling with a dietician or other health professional to reduce or stabilize body weight and make changes in diet quality, portion size, and meal frequency to improve glucose control and reduce long-term diabetes complications
- Physical activity: increasing physical activity, initially by walking daily, to benefit glucose control and weight maintenance
- Smoking: reducing or stopping cigarette smoking to improve glucose control and reduce diabetes complications.
American Diabetes Association diagnostic criteria for diabetes
| Testa | Threshold | Qualifier |
|---|---|---|
| A1C, or | ≥6.5% | Lab NGSP certified, standardized DCCT assay |
| Fasting glucose, or | ≥126 mg/dL | No caloric intake for at least 8 hours |
| 2-hour glucose, or | ≥200 mg/dL | After 75 g of anhydrous glucose |
| Random glucose | ≥200 mg/dL | Plus classic hyperglycemic symptoms or crisis |
| aResults should be confirmed by repeat testing DCCT: Diabetes Control and Complications Trial; NGSP: National Glycohemoglobin Standardization Program Source: References 21-23 | ||
Signs and symptoms of diabetes and diabetic ketoacidosis
| Diabetes |
| Frequent urination |
| Excessive thirst |
| Extreme hunger |
| Unusual weight loss |
| Increased fatigue |
| Irritability |
| Blurry vision |
| Diabetic ketoacidosisa |
| Thirst or very dry mouth |
| Constantly feeling tired |
| Dry or flushed skin |
| Nausea, vomiting, or abdominal pain |
| Difficulty breathing (short, deep breaths) |
| Fruity odor on breath |
| Difficulty paying attention or confusion |
| aVomiting is a sign of escalation Source: References 24,25 |
Components of diabetes care
| Self-care tasks | Tests/annual assessments |
|---|---|
| Self-monitoring of glucose | A1C (2 to 4 times/year) |
| Medication management | Urinary microalbumin |
| Meal planning | Fasting lipids |
| Exercise | Blood pressure |
| Smoking cessation | Dilated eye exam |
| Foot self-examination and foot care | Foot exam |
| Stress management | General health and cardiovascular exam |
Managing patients at risk for diabetes
| Prediabetes21 | Management |
|---|---|
| Impaired fasting glucose (100 to 125 mg/dL) | Weight reduction (7%) Activity (150 minutes/week) At least yearly glucose monitoring |
| Impaired glucose tolerance (2-hour plasma glucose: 140 to 199 mg/dL) | |
| Prediabetic A1C (5.7% to 6.4%) | |
| Metabolic syndrome (any 3)26 | Management |
| Waist circumferencea (men >40 inches; women >35 inches) | Weight reduction Reduce consumption of refined carbohydrates Exercise Focused interventions for individual criteria |
| Fasting triglycerides (≥150 mg/dL) | |
| Fasting high-density lipoprotein cholesterol (men | |
| Fasting glucose (≥100 mg/dL or taking medication) | |
| Blood pressure (≥130/85 mm Hg or taking medication) | |
| aWaist circumference guidelines are ethnicity specific. The International Diabetes Federation27 has published specific cutoffs for those of Asian background (men: ≥90 cm [35 inches] and women: ≥80 cm [31 inches]) | |
Metabolic monitoring
Metabolic monitoring is the key to keeping patients with schizophrenia well. Treating metabolic conditions falls outside of psychiatric practice; however, many argue that mental health clinicians should monitor basic metabolic parameters during antipsychotic treatment and advocate medical interventions when indicated because:
- most antipsychotics are associated with weight gain and metabolic side effects
- patients with schizophrenia have cognitive deficits that impact health maintenance
- mental health providers often are the primary health care contacts for patients with serious mental illness.
- identify treatable medical conditions such as diabetes, dyslipidemia, and hypertension when treatment delay or no treatment has consequences
- identify individuals with prediabetes and metabolic syndrome for targeted prevention
- determine the association between antipsychotic treatment and metabolic disturbance to evaluate the risk of treatment vs antipsychotic switching.
How to intervene
To switch or not to switch? For many psychiatrists, deciding whether or when to switch from a high or intermediate metabolic liability antipsychotic to one with low metabolic liability is difficult. Clinicians must balance potential metabolic benefits against the risk of psychotic decompensation and side effects. Ultimately, patients and their families make the decision, taking into account information provided to them. For medical-legal purposes, document the discussion of potential risks and benefits. These are difficult decisions and there are no clear guidelines. In my clinical experience, the following issues need to be considered:
- The antipsychotics that many clinicians consider to be the most effective—clozapine and olanzapine—also have the greatest metabolic liability and risk for emergent T2DM.
- Patients who are stable and in psychotic remission may risk a relapse of their illness if switched.
- The clearest indication for switching is when a patient who does not have diabetes develops the condition shortly after starting an antipsychotic. This scenario is rare, but evidence suggests that diabetes may resolve or reverse with an antipsychotic switch.33
- In patients who gain weight while taking a high- or intermediate-liability antipsychotic and are able to tolerate a switch to a low-liability antipsychotic, the effect size of weight reduction can be large and may result in a patient returning to their pretreatment weight.
- To reduce relapse risk, patients switching antipsychotics should be closely monitored at least weekly for ≥1 month. A plateau cross-taper—building the new antipsychotic up to therapeutic levels before gradually reducing the first antipsychotic—may be safer than abrupt discontinuation or standard cross-titration.
- Switching from one high or intermediate liability antipsychotic to another (eg, olanzapine to quetiapine or risperidone) often provides little if any metabolic benefit on body weight or diabetes control.
- Established diabetes (type 1 or type 2) should not be a contraindication to antipsychotic treatment, including clozapine, if clinically warranted. Monitor metabolic parameters more closely for 6 to 12 months after the switch. In most cases, patients experience limited, if any, metabolic consequences. If so, diabetes medication can be adjusted.
- Patients who have experienced significant weight gain on an atypical antipsychotic often do not gain more weight when switched to clozapine. A patient may reach a “ceiling” in terms of weight gain and medication-related metabolic effects.
