Pre-onset sub-threshold psychotic symptoms and cortical organization in the first episode of psychosis

Combinations and Temporal Associations Among Precursor Symptoms Before a First Episode of Psychosis

BACKGROUND AND HYPOTHESIS

Symptoms that precede a first episode of psychosis (FEP) can ideally be targeted by early intervention services with the aim of preventing or delaying psychosis onset. However, these precursor symptoms emerge in combinations and sequences that do not rest fully within traditional diagnostic categories. To advance our understanding of illness trajectories preceding FEP, we aimed to investigate combinations and temporal associations among precursor symptoms.

STUDY DESIGN

Participants were from PEPP-Montréal, a catchment-based early intervention program for FEP. Through semistructured interviews, collateral from relatives, and a review of health and social records, we retrospectively measured the presence or absence of 29 precursor symptoms, including 9 subthreshold psychotic and 20 nonpsychotic symptoms. Sequences of symptoms were derived from the timing of the first precursor symptom relative to the onset of FEP.

STUDY RESULTS

The sample included 390 participants (68% men; age range: 14-35 years). Combinations of precursor symptoms most frequently featured depression, anxiety, and substance use. Of 256 possible pairs of initial and subsequent precursor symptoms, many had asymmetrical associations: eg, when the first symptom was suspiciousness, the incidence rate ratio (IRR) of subsequent anxiety was 3.40 (95% confidence interval [CI]: 1.79, 6.46), but when the first symptom was anxiety, the IRR of subsequent suspiciousness was 1.15 (95% CI: 0.77, 1.73).

CONCLUSIONS

A detailed examination of precursor symptoms reveals diverse clinical profiles that cut across diagnostic categories and evolve longitudinally prior to FEP. Their identification may contribute to risk assessments and provide insights into the mechanisms of illness progression.

Dynamic association of the first identifiable symptom with rapidity of progression to first-episode psychosis

BACKGROUND

Rapid progression from the first identifiable symptom to the onset of first-episode psychosis (FEP) allows less time for early intervention. The aim of this study was to examine the association between the first identifiable symptom and the subsequent speed of illness progression.

METHODS

Data were available for 390 patients attending a catchment-based early intervention service for FEP. Exposure to non-psychotic and subthreshold psychotic symptoms was retrospectively recorded using semi-structured interviews. Outcomes following the onset of the first identifiable symptom were (1) time to onset of FEP and (2) symptom incidence rate (i.e. number of symptoms emerging per person-year until FEP onset). These outcomes were respectively analyzed with Cox proportional hazards and negative binomial regressions.

RESULTS

After Bonferroni correction, having a subthreshold psychotic (v. non-psychotic) symptom as the first symptom was not associated with time to FEP onset [hazard ratio (HR) = 1.39; 95% CI 0.94-2.04] but was associated with higher symptom incidence [incidence rate ratio (IRR) = 1.92; 95% CI 1.10-3.48]. A first symptom of suspiciousness was associated with shorter time to FEP onset (HR = 2.37; 95% CI 1.38-4.08) and higher symptom incidence rate (IRR = 3.20; 95% CI 1.55-7.28) compared to other first symptoms. In contrast, a first symptom of self-harm was associated with lower symptom incidence rate (IRR = 0.06; 95% CI 0.01-0.73) compared to other first symptoms. Several associations between symptoms and illness progression were moderated by the age at symptom onset.

CONCLUSIONS

Appreciating the content and timing of early symptoms can identify windows and treatment targets for early interventions in psychosis.

"First-episode psychosis: Structural covariance deficits in salience network correlate with symptoms severity"

BACKGROUND

Patterns of coordinated variations of gray matter (GM) morphology across individuals are promising indicators of disease. However, it remains unclear if they can help characterize first-episode psychosis (FEP) and symptoms' severity.

METHODS

Sixty-seven FEP and 67 matched healthy controls (HC) were assessed with structural MRI to evaluate the existence of distributed GM structural covariance patterns associated to brain areas belonging to salience network. Voxel-based morphometry (VBM) and structural covariance differences, investigated with salience network seed-based Partial Least Square, were applied to explore differences between groups. GM density associations with Raven's intelligent quotient (IQ) and Positive and Negative Syndrome Scale (PANSS) scores were investigated.

RESULTS

Univariate VBM results gave trend without significant GM differences across groups. GM and IQ correlated positively in both groups: in FEP, mostly in hippocampus, insula, and fronto-temporal structures, while in HC mostly in amygdala, thalamus and fronto-temporal regions. GM and PANSS scores correlated negatively in FEP, with widespread clusters located in limbic regions. Multivariate analysis showed strong and opposite structural GM covariance with salience network for FEP and HC. Moreover, structural covariance of the salience network in FEP correlated negatively with severity of clinical symptoms.

CONCLUSION

Our study provides evidence supporting the insular dysfunction model of psychosis. Reduced structural GM covariance of the salience network, with its association to symptom's severity, appears a promising morphometry feature for FEP detection.