Severe mental illness (SMI) has been associated with an increased risk of mortality, attributed to cardiometabolic disease, resulting largely from the side effects of antipsychotic medications (APM) and poor diet. Dietary interventions targeting nutritional challenges faced by individuals with SMI may improve cardiometabolic profiles and should be considered a priority to help reduce mortality risk in this particular population.
Severe mental illness (SMI) includes disorders like schizoaffective disorder, bipolar affective disorder, psychotic depression, and drug-induced and organic psychosis. It is generally characterized by psychosis, or loss of contact with reality. People with SMI may experience a variety of psychotic symptoms including delusions, hallucinations, and disturbances in speech and behavior. They may also experience symptoms commonly associated with depression such as a general lack of interest, pleasure, and motivation, as well as a tendency to withdraw.
SMI has been associated with an increased risk of mortality. Some sources suggest a 20-year mortality gap between people with SMI and those in the general population, and this gap continues to increase. It is largely the result of cardiometabolic disease, which is influenced by diet and lifestyle, yet lifestyle interventions that target diet and physical health in SMI often take a backseat to more traditional psychiatric and psychosocial treatments. Although dieticians have recently been recognized and integrated as valuable members of multi-disciplinary treatment teams, the evidence base that informs their clinical practice is lacking. In an effort to address these concerns, a group of Australian researchers conducted a literature review to assess dietary challenges in SMI and interventions to improve physical and mental health. Their review was published in the journal of Human Nutrition and Dietetics.
Weight gain is a well-recognized challenge faced by people with SMI. This challenge is not only a physical health concern; people who gain weight are also less likely to take their medications as prescribed. Weight gain is associated with the side effects of antipsychotic medications (APM) coupled with mental health symptoms that make it difficult for people with SMI to regulate eating behaviors, as well as the types and amounts of foods they consume. Side effects of APM like hunger that is hard to satisfy and mental health symptoms such as low motivation and depression make it difficult to curb overeating. Studies have also shown that SMI is associated with eating disorders like binge eating and fast-eating syndrome.
Cravings for processed foods that are high in sugar and fat and more affordable contribute to unhealthy diets among those with SMI. Studies have shown that these individuals are less likely to consume fruits and fiber, as well as vegetables, legumes, and dairy products, compared to the general population. They are also more likely to consume fast foods and sweet foods and drinks. In addition, individuals with SMI may have difficulty planning and executing daily tasks like meal planning, shopping, and cooking.
Rapid weight gain contributes to obesity and cardiometabolic disturbances among those with SMI. Side effects of APM, including the potential for weight gain and changes in lipid and glucose homeostasis, may explain increased risk for metabolic syndrome, diabetes, and hypercholesterolemia among those with SMI compared to the general population. Clinical guidelines have been established to assist health professionals in prescribing APM and monitor potential side effects. The potential for nutrient-medication interactions should also be monitored as substances such as caffeine, sodium, and grapefruit juice can interfere with APM.
Dieticians can plan and implement interventions to address diet-related concerns in SMI. Interventions that focus on meal planning and cooking skills and education regarding healthy food choices may improve diet among people with SMI. Mindful eating interventions may help clients to replace disordered eating behaviors with healthier habits. Dieticians should be prepared to address other diet-related issues among clients with SMI, such as gastro-oesophageal reflux disease, constipation, osteoporosis, and poor oral health. These conditions have been associated with the side effects of some medications, as well as the consequences of poor diet. Alcohol intake and smoking, low physical activity, and nutritional deficiencies are also common concerns in SMI.
Fortunately, evidence suggests that dietary interventions, especially those implemented in early psychosis when clients begin to take medications, can minimize weight gain and improve metabolic health. Individualized nutritional counseling can be used in the same way it is used with the general population, taking into account barriers faced by those with SMI and employing strategies to combat these barriers. Low levels of motivation, for example, can be addressed by holding counseling sessions when the client is least sedated and by celebrating small accomplishments to prevent discouragement, whereas increasing food literacy may improve poor nutritional intake.
Behavior change strategies based on theory should be incorporated into counseling sessions. As therapies like cognitive adaptive training and cognitive behavioral therapy have been used successfully to improve mental health outcomes, they may be effective at improving disordered eating behaviors in SMI, although further research is needed. Physical activity interventions delivered by exercise specialists may also improve physical and mental health for those with SMI.
In general, SMI is associated with a multitude of nutritional challenges that dieticians can target to improve overall health in this population. Further research should assess the effect of diet on mental health symptoms in those with SMI. Additionally, the potential role of gut microbiota on mood may yield evidence that could shape dietary interventions, although current evidence is lacking.
Written By: Suzanne M. Robertson, Ph.D