Objective:

To investigate the prevalence and extent of weight loss prior to diagnosis of first-episode psychosis (FEP) and its impact on subsequent weight gain.

Approach:

• Data Source: Utilized Clinical Practice Research Datalink primary care data, linked with hospital episode statistics, ethnicity, and deprivation data.
• Analysis Method: Employed multiple linear regression to assess the association between pre-FEP weight loss and subsequent weight change, adjusting for confounders.

Key Findings:

• 53% of individuals experienced weight loss before FEP.
• Individuals with pre-FEP weight loss gained weight post-FEP at over twice the rate of those without prior loss (8.93% (95% CI 6.90% to 10.96%) vs 4.07% (95% CI 1.90% to 6.24%); p=0.005).
• Each 1% of pre-FEP weight loss predicted an additional 0.41% (95% CI 0.23% to 0.59%) annual weight gain (p=0.004).
• Average weight gain post-FEP (6.49 kg (95% CI 5.28 kg to 7.70 kg)) exceeded average prior weight loss (4.83 kg (95% CI 4.00 kg to 5.66 kg)) by one year.

Interpretation:

Pre-FEP weight loss is common and significantly predicts rapid weight gain following diagnosis.

Limitations:

• The study is retrospective and relies on existing primary care data, which may not capture all relevant weight changes.
• Weight measurements were not systematically recorded in routine healthcare.

Conclusion:

Pre-FEP weight loss is prevalent and associated with increased weight gain post-diagnosis.