Identifying Hidden Causes of: Protocol & Guide

First-episode psychosis (FEP) is a complex mental health condition characterized by the sudden onset of psychotic symptoms, such as hallucinations and delusions. According to editorial research analyzed by Groundwork, While the exact causes of FEP are still not fully understood, research suggests that it is often linked to underlying medical conditions, substance use, or a combination of both.

In Asian populations, the prevalence and pattern of secondary causes of FEP are understudied. A recent 10-year retrospective study in Hong Kong aimed to investigate the prevalence and pattern of secondary causes of FEP in an acute medical setting.

The study found that secondary causes of psychosis were present in 9.6% of patients with FEP, with substance use being the most common underlying cause.

Methodology

The study employed a retrospective observational design, reviewing medical records of patients referred to the consultation psychiatry team at a tertiary acute teaching hospital in Hong Kong from January 2015 to April 2025. The inclusion criteria were:

• Age 18-64 at the time of assessment
• FEP confirmed by the consultation liaison team
• Patients diagnosed with delirium were excluded

Key Findings and Data Analysis

Among the 384 patients included in the study, secondary causes of psychosis were found in 9.6% (n=37) of the cohort. The most common secondary cause was substance use, accounting for 2.9% of all FEPs.

Breakdown of Secondary Causes

Definitive or Probable Autoimmune Encephalitis

Among the patients with secondary psychoses, 16 underlying conditions were revealed only by the workup in relation to the FEP. Definitive or probable autoimmune encephalitis was the most common condition uncovered, affecting 5 patients.

Early-Onset Dementia

Early-onset dementia was another common condition found in 4 patients. This highlights the importance of considering dementia as a potential underlying cause of FEP, especially in patients with otherwise unremarkable past history and toxicology test.

Clinical Implications

The study's findings have significant clinical implications for healthcare providers. Clinicians need to be aware of suspicious clinical features suggestive of autoimmune encephalitis and early-onset dementia in FEP patients. A thorough workup, including toxicology tests and imaging studies, is essential to uncover underlying conditions.

The prevalence of secondary psychoses in the FEP cohort was lower than published international figures. However, the study's findings emphasize the importance of considering secondary causes of FEP, particularly in patients with substance use or unexplained clinical features.