Table 1.
Studies describing therapeutic effects of the ketogenic diet in schizophrenia.
| Author(s), Year | Study Design | Number of Participants (Intervention/Control) | Range Age of Participants (Years) | Dietary Intervention/ Assessment of Ketosis |
Control Intervention |
Duration | Outcome Measures | Main Findings |
|---|---|---|---|---|---|---|---|---|
| Pacheco et al., 1965 [61] | Pilot study | I: 10 (F) | 19–63 | KD, lack of detailed information | none | 2 weeks | A nursing checklist for ward behavior ratings, The Minimal Social Behavior Scale, The Beckomberga Rating Scale for the S-Factor | ↓symptomatology, ↑symptomatology after discontinuing the KD |
| Kraft et al., 2009 [64] | Case study | I: 1 (F) | 70 | gluten and low-carbohydrate KD, (<20 g carbohydrates per day), ketosis was not confirmed | none | 1 year | Patients’ and physicians’ observations | ↓symptomatology (visual and auditory hallucinations), ↓body weight, ↑energy level |
| Palmer et al., 2019 [63] | Two case studies | I: 2 (F) | 82 and 39 | KD, lack of detailed information | none | 5 years and 12 years | Patients’ and physicians’ observations | ↓symptomatology, ↓body weight, ↓the amount of taken medications |
| Sethi et al., 2024 [62] |
Pilot study | I: 5 | 18–75 | KD, 10% carbohydrate, 30% protein, 60% fat; ≥5040 kJ, <20 g carbohydrates per day; blood ketone meter at least once a week | none | 4 months | Generalized Anxiety Disorder (GAD–7), Patient Health Questionnaire Depression Scale (PHQ–9), Pittsburgh Sleep Quality Index (PSQI), Clinical Mood Monitoring Forms (CMF), Clinical Global Impression–Schizophrenia (CGI–SCH) Scale, Global Assessment of Functioning (GAF), Manchester Short Assessment of Quality of Life (MANSA), Brief Psychiatric Rating Scale (BPRS) for Schizophrenia and screening for suicidality; HbA1c, fatty acid profile, hsCRP, HOMA-IR, HOMA2-IR, advanced lipid testing, body weight, blood pressure, HR, waist circumference, body composition analysis |
32% reduction in Brief Psychiatric Rating Scale, ↑proportion of participants who were in the recovery state at baseline *, ↑sleep quality *, improvement in cognition and mood, ↓anxiety, ↓depressive symptoms *, improvement in CGI scale, ↑life quality and satisfaction *, ↓body weight, waist circumference, systolic blood pressure, FMI, BMI *, ↓visceral adipose tissue, HbA1c, triglycerides, HOMA-IR * |
F—females; M—males; KD—ketogenic diet; HbA1c—glycosylated hemoglobin; HOMA-IR—the homeostasis model assessment-estimated insulin resistance; hs-CRP—high sensitivity C-reactive protein; HR—heart rate; FMI—fat mass index; BMI—body mass index; * all participants (patients with SZ and BD analyzed as one group); I—intervention; C—control.