Psychiatry · Medical Literature
Longitudinal Dietary Intake of Young People With a First Episode of Psychosis From the Time of Presentation to Six Months Follow-Up.
Abstract
Antipsychotic medications stimulate appetite and weight gain, contributing to high obesity rates in people with psychotic disorders. It is unknown if these dietary effects habituate over time. This study aimed to determine the dietary intake of young people with a first-episode psychosis at the time of presentation and at three- and six-months of follow-up. We assessed dietary patterns at baseline, 3 months, and 6 months in participants diagnosed with first-episode psychosis who had minimal prior antipsychotic exposure. We analysed data from the PHAstER randomised-controlled trial, assessing changes in food consumption and Australian Dietary Guideline compliance using signed-rank tests with corrections for multiple testing. Of the 77 PHAstER study participants, 70 participants (91%) provided dietary data at baseline and 46 (60%) at 3 and 6 months. Dietary intake patterns and compliance with dietary guidelines remained consistent across all three timepoints. At baseline, few met recommended intake of three major food groups: vegetables (13%), dairy (20%) and fruit (24%). 64% of participants had a high intake of discretionary food (food high in saturated fat/sugars). At baseline, but not at three- or six-months, higher education levels were associated with healthier dietary patterns. Participants consistently reported unhealthy diets that did not adhere to guidelines, with no significant change over 6 months. This study reinforces the inequity of dietary health in people with psychosis, particularly those with lower levels of education. Dietary advice and support represent interventions with high marginal gain in this cohort, and should be part of routine clinical care.
Clinical relevance
This study addresses a critical gap in understanding the longitudinal trajectory of dietary behavior in young people presenting with first-episode psychosis (FEP), a population at disproportionately high risk for metabolic comorbidities partly attributable to antipsychotic-induced appetite stimulation and weight gain. It directly examines whether dietary habits change — or habituate — over the first six months of antipsychotic treatment, a period of maximum metabolic vulnerability. Clinicians managing FEP must recognize that baseline dietary inadequacy persists throughout early treatment, underscoring the urgent need to integrate nutritional interventions into standard early psychosis care protocols.
Key findings
1. Of 77 PHAstER RCT participants with minimal prior antipsychotic exposure, 70 (91%) provided dietary data at baseline, with retention declining to 46 participants (60%) at both 3- and 6-month follow-up timepoints. 2. Dietary intake patterns and compliance with Australian Dietary Guidelines showed no statistically significant change across any of the three timepoints (baseline, 3 months, 6 months), as assessed by signed-rank tests with corrections for multiple testing, suggesting no habituation or deterioration of dietary behavior over the observed period. 3. At baseline, guideline-recommended intake was met by only 13% of participants for vegetables, 20% for dairy, and 24% for fruit — indicating pervasive micronutrient and macronutrient insufficiency at illness onset. 4. 64% of participants reported high intake of discretionary foods (defined as foods high in saturated fat and/or added sugars) at baseline, a pattern that persisted across follow-up. 5. Higher education level was significantly associated with healthier dietary patterns at baseline but not at 3- or 6-month follow-up, highlighting a socioeconomic gradient in nutritional health that attenuates over the early treatment course. 6. The consistency of unhealthy dietary patterns across all timepoints — independent of antipsychotic initiation — suggests that poor diet in this cohort reflects pre-existing behavioral and socioeconomic factors, not solely pharmacological effects, though the study design does not permit causal attribution.
Practice implications
Early psychosis clinicians should implement structured dietary screening and nutritional counseling at the time of FEP presentation — not deferred to later follow-up — given that dietary inadequacy is already pronounced at illness onset and does not self-correct over six months of treatment. Interventions should be prioritized for patients with lower educational attainment, who demonstrate persistently poorer dietary quality and represent a high-risk subgroup for metabolic syndrome and cardiovascular disease. Dietary advice and support — including referral to a dietitian and education on discretionary food reduction and vegetable/fruit/dairy intake — should be embedded as a routine component of early intervention in psychosis (EIP) service pathways, alongside metabolic monitoring, given the high marginal gain achievable in this nutritionally deficient cohort.