Dietary modification in the treatment of schizophrenia spectrum disorders: A systematic review

Keto therapy-unveiling the potential of ketogenic diet in psychiatric care: A scoping review

BACKGROUND

Within the framework of gut-brain interactions, the ketogenic diet (KD), a high-fat, low-carbohydrate, and moderate-protein dietary intervention, has gained attention for its potential in psychiatric care. Renowned for its efficacy in managing obesity, KD has demonstrated effectiveness in facilitating weight loss and inducing favorable metabolic changes in the short term. With its established benefits in neurological disorders, KD is now being investigated as a potential therapeutic avenue for individuals with psychiatric conditions.

OBJECTIVE

This scoping review aims to summarize the latest studies on this topic, consider clinical implications, and suggest future research directions.

METHODS

Records were systematically (PRISMA-ScR guidelines) identified through PubMed, Scopus, and EBSCOhost searches.

RESULTS

A total of 58 studies were initially identified, with 13 meeting the eligibility criteria. While clinical trials remain limited, emerging evidence from case reports, case series, and pilot studies highlights the potential of a KD in reducing symptoms across psychiatric conditions, including mood disorders, psychotic disorders, alcohol use, and eating disorders. A KD shows potential in reducing cravings in eating and alcohol use disorders by stabilizing brain metabolism and modulating addictive behaviors, while its neuroprotective and anti-inflammatory effects may contribute to symptom improvement in mood and psychotic disorders.

CONCLUSIONS

Implementing a KD in patients with mental disorders seems to be a feasible and well-tolerated approach, resulting in psychiatric symptom reduction and improvements in metabolic health. Most interestingly, research suggests that KD can also be safely implemented in the care of patients with addictive-like eating disorders.

Intuitive eating predictors and outcomes in people with severe mental illness participating in a lifestyle intervention

ISSUE ADDRESSED

People with severe mental illness (SMI) are at higher risk of preventable diseases than the general population; poor diet contributes to heightened risk. Adaptive approaches designed to improve intuitive eating may improve dietary behaviours in people with SMI. Aims of this study were to investigate predictors of, and assess the impact of a nutrition program on, intuitive eating in people with SMI.

METHODS

This was a retrospective analysis of an exercise and nutrition program for people with SMI. The primary outcome was intuitive eating assessed using the Intuitive Eating Scale 2 (IES2); psychological distress was measured using the Kessler-6 scale. Regression analyses were conducted on baseline data; change in intuitive eating was assessed using Wilcoxon tests.

RESULTS

A total of 93 participants had complete data for regression analyses, and 32 completed pre/post-assessments. The most common mental health diagnosis was psychotic disorder (35%); 74% had BMI > 25 kg/m2. The regression model significantly predicted total IES2 score and three intuitive eating domains. Body mass index (BMI) was negatively associated with these outcomes (β = -0.234 to -0.248; p < 0.05). Both BMI and psychological distress were negatively associated with body-food choice congruence (B-FCC), and only B-FCC was improved at post-intervention.

CONCLUSIONS

Higher BMI and psychological distress were associated with lower intuitive eating in people with SMI. Nutrition interventions may improve B-FCC in people with SMI. SO WHAT?: Given the interrelatedness of BMI and psychological distress with psychosocial stressors, nutritional interventions should be implemented alongside holistic approaches to improve health equality.

EPA guidance on lifestyle interventions for adults with severe mental illness: A meta-review of the evidence

There is growing interest in lifestyle interventions as stand-alone and add-on therapies in mental health care due to their potential benefits for both physical and mental health outcomes. We evaluated lifestyle interventions focusing on physical activity, diet, and sleep in adults with severe mental illness (SMI) and the evidence for their effectiveness. To this end, we conducted a meta-review and searched major electronic databases for articles published prior to 09/2022 and updated our search in 03/2024. We identified 89 relevant systematic reviews and assessed their quality using the SIGN checklist. Based on the findings of our meta-review and on clinical expertise of the authors, we formulated seven recommendations. In brief, evidence supports the application of lifestyle interventions that combine behavioural change techniques, dietary modification, and physical activity to reduce weight and improve cardiovascular health parameters in adults with SMI. Furthermore, physical activity should be used as an adjunct treatment to improve mental health in adults with SMI, including psychotic symptoms and cognition in adults with schizophrenia or depressive symptoms in adults with major depression. To ameliorate sleep quality, cognitive behavioural informed interventions can be considered. Additionally, we provide an overview of key gaps in the current literature. Future studies should integrate both mental and physical health outcomes to reflect the multi-faceted benefits of lifestyle interventions. Moreover, our meta-review highlighted a relative dearth of evidence relating to interventions in adults with bipolar disorder and to nutritional and sleep interventions. Future research could help establish lifestyle interventions as a core component of mental health care.

Educational Nutrition Workshops: Impact on Nutritional Status in Organized Living Beneficiaries with Severe Mental Disorders and Their Caregivers

BACKGROUND/OBJECTIVES

Individuals with severe mental disorders often face challenges in maintaining a healthy lifestyle, including proper dietary habits. Educational nutrition workshops, as a form of nutritional intervention, may play an important role in improving their nutritional status. This study aims to assess the impact of nutritional workshops on the dietary habits and nutritional status of individuals with severe mental disorders and their caregivers.

METHODS

This study involved 65 participants, namely 46 individuals with mental disorders living in organized settings (beneficiaries) and 19 caregivers. The nutritional intervention consisted of two cycles of workshops, encompassing a total of four educational workshops.

RESULTS

Results before and after the intervention showed positive changes in nutritional status and dietary intake. Beneficiaries lost on average 3.5 kg of body weight, while body fat decreased by 3.5% and visceral fat by 1.9 points. In the group of caregivers, body fat decreased by 3.2%. Energy intake (p < 0.05), total fat (p < 0.01), saturated fatty acid (p < 0.05), polyunsaturated fatty acid (p < 0.05), and sodium (p < 0.05) intake decreased in beneficiaries compared to intake before workshops, while dietary fiber (p < 0.05), vitamin C (p < 0.05), and fruit (p < 0.01) intake increased. In caregivers, the decrease in carbohydrate (p < 0.05), total sugar (p < 0.01), and dietary fiber (p < 0.05) intake was recorded.

CONCLUSION

This study provides a strong foundation for future research and the implementation of educational programs as part of comprehensive care for individuals with severe mental disorders.

Conceptualization and characterization of "primary" and "secondary" cognitive impairment in schizophrenia

Cognitive impairment represents one of the core features of schizophrenia, involves both neurocognition and social cognition domains, and has a significant negative impact on real-world functioning. The present review provides a framework for the conceptualization and characterization of "primary" and "secondary" cognitive impairment in schizophrenia. In this conceptualization, primary cognitive impairment can be defined as a consequence of the neurobiological alterations that underlie psychopathological manifestations of the disorder, while secondary cognitive impairment can be defined as the results of a source issue that has a negative impact on cognitive performance. Sources of secondary cognitive impairment are frequent in people with schizophrenia and include several different factors, such as positive and negative symptoms, depressive symptoms, autistic symptoms, pharmacotherapy, substance abuse, metabolic syndrome, social deprivation, and sleep disorders. It can be hypothesized that secondary cognitive impairment may be improved by effectively resolving the source issue, while primary cognitive impairment may benefit from dedicated treatment. Further research is required to confirm this hypothesis, to better characterize the distinction between primary and secondary cognitive impairment in a clinical and in a neurobiological perspective, and to evaluate the impact of systematically assessing and treating secondary cognitive impairment.

An Anti-Inflammatory Diet and Its Potential Benefit for Individuals with Mental Disorders and Neurodegenerative Diseases-A Narrative Review

This narrative review synthesizes current evidence regarding anti-inflammatory dietary patterns and their potential benefits for individuals with mental disorders and neurodegenerative diseases. Chronic low-grade inflammation is increasingly recognized as a key factor in the etiology and progression of these conditions. The review examines the evidence for the anti-inflammatory and neuroprotective properties of dietary components and food groups, focusing on whole foods rather than specific nutrients or supplements. Key dietary components showing potential benefits include fruits and vegetables (especially berries and leafy greens), whole grains, legumes, fatty fish rich in omega-3, nuts (particularly walnuts), olive oil, and fermented foods. These foods are generally rich in antioxidants, dietary fiber, and bioactive compounds that may help modulate inflammation, support gut health, and promote neuroprotection. Conversely, ultra-processed foods, red meat, and sugary beverages may be harmful. Based on this evidence, we designed the Brain Anti-Inflammatory Nutrition (BrAIN) diet. The mechanisms of this diet include the modulation of the gut microbiota and the gut-brain axis, the regulation of inflammatory pathways, a reduction in oxidative stress, and the promotion of neuroplasticity. The BrAIN diet shows promise as an aid to manage mental and neurodegenerative disorders.

Dietary interventions to improve metabolic health in schizophrenia: A systematic literature review of systematic reviews

AIM

This review of systematic reviews synthesised evidence on the impact of dietary interventions on anthropometric and biochemical measures associated with schizophrenia and metabolic syndrome. Secondly, an aim to identify intervention elements associated with greater dietary adherence and behaviour change.

METHODS

Five databases were searched from 2000-March 2023. Eligible reviews included adults, majority diagnosed with schizophrenia, dietary intervention components and at least one anthropometric or biochemical outcome related to metabolic syndrome. Two independent reviewers performed article selection, data extraction, and quality assessment.

RESULTS

Seven systematic reviews, consisting of 79 unique primary papers were included. No reviews exclusively examined dietary interventions. Nutrition education and counselling administered alongside physical activity were common. All reviews favoured intervention over the control to reduce body weight, body mass index, and waist circumference. Glycaemic control, blood pressure and triglycerides were not routinely reported with mixed effects following interventions. There was insufficient data to examine any trends for dropout rates, dietary adherence, and behaviour change. There was both low (n = 3/7) and high (n = 4/7) risk of bias and degree of study overlap was very high (16.4 %). The level of evidence was rated as suggestive (n = 2/7), weak (n = 2/7), non-significant (n = 1/7) and ungraded (n = 2/7).

CONCLUSION

Dietary interventions administered alongside lifestyle therapies can reduce anthropometric measurements for consumers living with schizophrenia and prescribed antipsychotic medications. Higher quality reviews with greater strength and credibility of evidence are required. Uniform reporting of intervention elements is also necessary for cross comparison of efficacious elements and synthesis of evidence at higher levels to advance dietetic practice and inform future policies.

Adherence to Dietary Recommendations in Organized Living Beneficiaries with Severe Mental Disorders and Their Caregivers

People with severe mental disorders often require special care. Other than institutionalized care, some organizations provide housing options and special care in the form of organized living. Few studies provide a detailed description of nutrient intake in this type of care. The aim of this prospective study was to assess nutritional status and adherence to dietary recommendations in both people with mental disorders (beneficiaries) and their caregivers. Across three levels of care, 46 beneficiaries and 19 caregivers participated in the study. The mean intakes of energy (kcal/day) and macro- and micronutrients (g/day) were estimated from a 3-day dietary record and compared with dietary reference values (DRVs) set by the European Food Safety Authority (EFSA). The majority of participants did not meet energy intake recommendations (kcal/day). The contribution of total fat to energy intake (% E) was higher than recommended in both beneficiaries and caregivers with 42.1 ± 4.4% and 38.5 ± 6.5%, respectively. A total of 45.2% of beneficiaries and 61.1% of caregivers had their carbohydrate intake within the recommended range. Fiber intake was well below the recommendations (25 g/day) in all groups. Across all levels of care, lower micronutrient intake for pantothenic acid, biotin, folate, potassium, magnesium, copper, selenium, and iodine was observed. Based on the current results, the development and implementation of nutritional guidelines may be targeted to specific populations and nutrient intakes.

Effectiveness of dietary interventions in mental health treatment: A rapid review of reviews

AIM

This rapid review of reviews aimed to determine the extent of research undertaken on the effectiveness of dietary interventions for individuals with a mental disorder.

METHODS

Three databases (MEDLINE, Embase, Cochrane Reviews and Cochrane Trials) were searched to February 2021 for systematic reviews including experimental studies assessing the effectiveness of dietary interventions with physical or mental health related outcomes in adults or children with one or more of: severe mental illness, depression or anxiety, eating disorders, or substance use disorder. Results are presented descriptively.

RESULTS

The number of included reviews was 46 (67% in severe mental illness, 20% in depression and anxiety, 7% in eating disorders, and 7% in substance use disorders). Most reviews were published since 2016 (59%), and included studies conducted in adults (63%). Interventions in the eating disorders and severe mental illness reviews were predominantly education and behaviour change, whereas interventions in the substance use disorders, and depression and anxiety reviews were predominantly supplementation (e.g. omega-3). Twenty-eight and twelve of the reviews respectively reported mental health and dietary outcomes for one or more included studies. Most reviews in severe mental illness, and depression and anxiety reported conclusions supporting the positive effects of dietary intervention, including positive effects on weight-related or mental health outcomes, and on mental health outcomes, respectively.

CONCLUSIONS

A larger number of systematic reviews were identified which evaluated dietary interventions in individuals with severe mental illness, and depression and anxiety, compared with substance use disorders, and eating disorders. Dietary intervention is an important component of the treatment that should be available to individuals living with mental disorders, to support their physical and mental health.

The efficacy of nutritional supplements for the adjunctive treatment of schizophrenia in adults: A systematic review and network meta-analysis

Nutritional supplementations have been widely used as adjunctive treatments for schizophrenia. However, among these supplementations, of which the most beneficial is currently unknown. This study aimed to compare and rank the effectiveness of nutritional supplementations in the adjunctive treatments of schizophrenia. The four nutritional supplementations evaluated were: 1) folate acid or vitamin B12; 2) vitamin D; 3) N-acetyl cysteine (NAC); 4) Omega-3 polyunsaturated fatty acid, including docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). 17 eligible RCTs with 1165 participants were included in this network meta-analysis based on study criteria. NAC supplementation was significantly more efficacious than folic acid or vitamin B12 [MD (95% CI): -6.6 (-10.8, -2.4)] and omega-3 polyunsaturated fatty acid [MD (95% CI): -5.1(-9.9, -0.8)] supplementation in the term of PANSS score changes. There were no significant differences in the PANSS score changes between NAC and vitamin D [MD (95% CI): -5.2 (-10.9, 0.5)] supplementations. The estimated ranking probabilities of treatments showed that NAC might be the most effective adjunctive intervention over all nutritional supplementations. These results indicate that NAC could improve PANSS score and it may be among the most effective nutritional supplementations in schizophrenia patients.

Patient-reported outcomes of lifestyle interventions in patients with severe mental illness: a systematic review and meta-analysis

BACKGROUND

Lifestyle interventions for severe mental illness (SMI) are known to have small to modest effect on physical health outcomes. Little attention has been given to patient-reported outcomes (PROs).

AIM

To systematically review the use of PROs and their measures, and quantify the effects of lifestyle interventions in patients with SMI on these PROs.

METHODS

Five electronic databases were searched (PubMed/Medline, Embase, PsycINFO, CINAHL, and Web of Science) from inception until 12 November 2020 (PROSPERO: CRD42020212135). Randomised controlled trials (RCTs) evaluating the efficacy of lifestyle interventions focusing on healthy diet, physical activity, or both for patients with SMI were included. Outcomes of interest were PROs.

RESULTS

A total of 11.267 unique records were identified from the database search, 66 full-text articles were assessed, and 36 RCTs were included, of which 21 were suitable for meta-analyses. In total, 5.907 participants were included across studies. Lifestyle interventions had no significant effect on quality of life (g = 0.13; 95% CI = - 0.02 to 0.27), with high heterogeneity (I² = 68.7%). We found a small effect on depression severity (g = 0.30, 95% CI = 0.00 to 0.58, I² = 65.2%) and a moderate effect on anxiety severity (g = 0.56, 95% CI = 0.16 to 0.95, I² = 0%).

DISCUSSION

This meta-analysis quantifies the effects of lifestyle interventions on PROs. Lifestyle interventions have no significant effect on quality of life, yet they could improve mental health outcomes such as depression and anxiety symptoms. Further use of patient-reported outcome measures in lifestyle research is recommended to fully capture the impact of lifestyle interventions.

Development of Decision Support System Platform for Daily Dietary Plan

Background:

Solving many health issues needs accurate and significant information in food consumption. Recently, data analysis and communication provided outstanding and robust approaches to fulfill the necessity of scientific information and help in decision making in many fields. Many evidence reported that with little information better decisions can be achieved.

Objective:

This research aimed to develop the Decision Support System (DSS) for the daily dietary plan to practically help users in food consumption and health care.

Methods:

The system consists of 1,940 cuisine items, including Thai and English menus. In this system, the user can set the daily dietary plan by selecting menu items with food specific and total calories. Overall calories of selected menu items would be calculated automatically. The user can see the normal range of calories required based on gender with the help of the baseline (normal office person).

Results:

This system can help users to become familiar with a better daily dietary plan, food calories, and health care easily. Furthermore, experts (doctors) can improve their learning experiences by formulating and adjusting the Decision Support System (DSS) for patients in special need. The easiness and usefulness of this system were evaluated by 119 users on Likert scale (1=least, 5=most). The result on average was 4.58.

Conclusion:

The Decision Support System (DSS) for the daily dietary plan was developed. The accessibility to the system is via personal computer (PC), smartphone, and tablet with internet connection. For future work, this DSS can improve by connecting the platform with health care providers via sharing the data for more online support.

The Deficit Schizophrenia Subtype Is Associated with Low Adherence to the Mediterranean Diet: Findings from a Case–Control Study

Accumulating evidence indicates that individuals with schizophrenia show poor dietary habits that might account for increased susceptibility to cardiovascular diseases in this population. However, it remains unknown whether this observation can be generalized over the whole population of individuals with schizophrenia. Therefore, in this study we aimed to investigate dietary habits, in terms of adherence to the Mediterranean diet (MD) in subjects with the deficit subtype of schizophrenia (SCZ-D), those with non-deficit subtype (SCZ-ND), and healthy controls (HCs). We recruited 45 individuals with SCZ-ND, 40 individuals with SCZ-D, and 60 HCs. Dietary habits were assessed using the Food Frequency Questionnaire-6 with a 12-month recall. Adherence to MD was decreased only in subjects with SCZ-D compared with HCs. Lower adherence to MD was associated with significantly higher levels of clinician-rated and self-reported negative symptoms (including alogia, avolition, and anhedonia). No significant correlations of adherence to MD with depressive symptoms were found. Lower adherence to MD was related to significantly higher body mass index in subjects with schizophrenia, but not in HCs. Our results indicate that poor adherence to MD is associated with a diagnosis of SCZ-D, higher severity of negative symptoms, and greater risk of developing overweight or obesity.

European Psychiatric Association guidance on treatment of cognitive impairment in schizophrenia

Background

Although cognitive impairment is a core symptom of schizophrenia related to poorer outcomes in different functional domains, it still remains a major therapeutic challenge. To date, no comprehensive treatment guidelines for cognitive impairment in schizophrenia are implemented.

Methods

The aim of the present guidance paper is to provide a comprehensive meta-review of the current available evidence-based treatments for cognitive impairment in schizophrenia. The guidance is structured into three sections: pharmacological treatment, psychosocial interventions, and somatic treatments.

Results

Based on the reviewed evidence, this European Psychiatric Association guidance recommends an appropriate pharmacological management as a fundamental starting point in the treatment of cognitive impairment in schizophrenia. In particular, second-generation antipsychotics are recommended for their favorable cognitive profile compared to first-generation antipsychotics, although no clear superiority of a single second-generation antipsychotic has currently been found. Anticholinergic and benzodiazepine burdens should be kept to a minimum, considering the negative impact on cognitive functioning. Among psychosocial interventions, cognitive remediation and physical exercise are recommended for the treatment of cognitive impairment in schizophrenia. Noninvasive brain stimulation techniques could be taken into account as add-on therapy.

Conclusions

Overall, there is definitive progress in the field, but further research is needed to develop specific treatments for cognitive impairment in schizophrenia. The dissemination of this guidance paper may promote the development of shared guidelines concerning the treatment of cognitive functions in schizophrenia, with the purpose to improve the quality of care and to achieve recovery in this population.

Effectiveness of a complex psychosocial intervention to reduce metabolic syndrome in psychiatric outpatients with severe/persistent mental illness

The prevalence of metabolic syndrome among individuals with severe mental illness is considerably higher than in the general population, contributing to the 15–20-year shorter life expectancy of this client population. The aim of this pilot study was to evaluate the effectiveness of a novel, complex psychosocial program to reduce metabolic syndrome. Members of both the intervention (n = 78) and control (n = 31) group were psychiatric outpatients with severe/persistent mental illness struggling with one or more symptoms of metabolic syndrome. Beyond the default elements of similar programs such as diet and exercise, the intervention covered medication use, sleep hygiene, stress management, as well as addressing spiritual needs, mindfulness, addictions, and self-care. Assessment of metabolic indicators were completed at baseline, at the end of the 11-week intervention, and 6 months post-intervention. The trajectory of change over time was significantly more favorable in the treatment than in the control group in terms of waist circumference (p = 0.013, η² = 0.093) and a positive trend emerged in relation to blood glucose level (p = 0.082, η² = 0.057). However, no statistically reliable difference was observed between the intervention and the control group regarding the other outcome variables (body mass index, systolic and diastolic blood pressure, serum triglyceride level, serum HDL cholesterol level, overall metabolic syndrome severity). These findings suggest that to produce more robust benefits, psychosocial interventions targeting the metabolic health of individuals with complex mental health needs should be either longer in duration if resources permit or narrower in focus (diet and exercise mainly) if resources are scarce.

Dietary Glutamic Acid, Obesity, and Depressive Symptoms in Patients With Schizophrenia

Introduction: Schizophrenia is a lifelong condition associated with several comorbid conditions such as physical illnesses like obesity, as well as co-occurring psychiatric symptoms such as depression. Research regarding susceptibility to some of these comorbidities has primary focused on genetic risks or neurotransmitters and very little work has been done to understand environmental factors such as diet. In particular, understanding the role of dietary glutamic acid consumption on co-morbidities in patients with schizophrenia is important, as evidence suggests that glutamic acid consumption may directly influence glutamatergic neurotransmission; a key neurotransmitter related to schizophrenia, its associated co-morbidities, and depression. Therefore, the aim of this study was to examine the potential relationship between dietary glutamic acid and depressive symptomatology in patients with schizophrenia, stratified by obesity status, due to its relationship with inflammation, antipsychotic use, and depressive symptoms. Methods: Subjects included in this analysis, were part of a parent cross-sectional study in which included three dietary recalls analyzed using protocols outlined as part of the National Health and Nutrition Examination Surveys (NHANES) standardized criteria. Additionally, body mass index (BMI), and Beck Depression Inventory were obtained at this visit. Subjects with a BMI ≥ 30 kg/m2 were included in the obesity group, and the relationship between glutamic acid consumption and BDI scores was analyzed after controlling for age, race, sex, antidepressant and antipsychotic use, and animal and vegetable protein intake which provide natural forms of dietary glutamic acid. Results: A total of 168 participants were included in this study, of which 42.5% were female and 52.9% were White. The mean BMI for the group as a whole was 33.5 ± 8.7 (kg/m2) and the mean BDI was 14.5 ± 10.2 (range 2-50). No differences were found between obesity groups, other than a greater hyperlipidemia, hypertension, and lower waist to hip ratio. Overall, no relationship was found between dietary glutamic acid and BDI scores, However, for non-obese participants, diets higher levels of glutamic acid were associated with greater depression symptomatology (p = 0.021). Conclusion: These preliminary results indicate a possible correlation between dietary glutamic acid a depressive symptoms in non-obese patients with schizophrenia, although further research is needed to specifically examine this relationship.