Pharmacological Interventions in CHR-P (Antipsychotics, Omega-3)

What the evidence says

The randomized evidence on antipsychotics in people at clinical high risk for psychosis (CHR-P) finds no measured effect on transition to psychosis. A meta-analysis of 4 RCTs gave odds ratios of 0.63 at 6 months (95% CI 0.31–1.27) and 0.87 at 12 months (95% CI 0.32–2.32). Both intervals cross 1. A separate review reports that meta-analyses find no robust evidence that any pharmacological intervention beats needs-based care on attenuated positive symptoms or transition risk. It also states that no pharmacological intervention is licensed for CHR-P.

Omega-3 fatty acids show the same pattern in a meta-analysis of 4 RCTs. The odds ratios were 0.93 at 6 months, 0.72 at 12 months and 0.41 at 36 months or later. Every confidence interval crosses 1, and heterogeneity is high (I² 66%, 71% and 83%). A single RCT of minocycline, alone or with omega-3, also found no difference in transition rates among three groups. The text reports no effect sizes for it.

Combining CBT with risperidone is the one regimen with a short-term reduction. Against supportive therapy plus placebo, a meta-analysis of 2 RCTs found an odds ratio of 0.29 at 6 months (95% CI 0.09–0.91). By 12 months the odds ratio was 0.55 (95% CI 0.24–1.28), and the one RCT with 18-month data was also null. A second review describes low-dose antipsychotics as reducing transition at 6 months, with the effect fading by 12 months.

Observational data point the other way. In a meta-analysis, CHR-P people already exposed to antipsychotics at baseline had a transition rate of 29.9% (95% CI 25.1%–34.8%). Unexposed people in the same studies had 17.2% (15.1%–19.4%), and people in samples that excluded exposed individuals had 16.2% (14.6%–17.8%). A second meta-analysis reports the same direction. The sources describe this as an association. They state that the mechanism is unclear, and the extraction notes that dopamine supersensitivity and more severe baseline cases are both unresolved explanations. Among exposed people, monotherapy or low-dose regimens are associated with lower transition rates, but no magnitudes are given.

Antipsychotics are reported to manage attenuated psychotic symptoms in the acute phase. They are also associated with weight gain, Parkinsonian symptoms, sexual dysfunction and sedation. Higher doses and polypharmacy are linked to adverse effects across metabolic, neurological and cognitive domains. The sources give no CHR-P-specific incidence for these effects.

Evidence for omega-3 mechanisms comes from animal and mechanistic work, not from transition outcomes. In rats, n-3 deficiency produces mesocortical dopamine hypoactivity and mesolimbic hyperactivity. In mice with NMDA receptor hypofunction, n-3 supplementation did not rescue behavioral deficits. In ultra-high-risk individuals, a trial reports that complement proteins mediated the effect of n-3 on symptom severity. A review notes that cannabidiol reduced symptom severity in CHR-P in trial data, but gives no sample size or magnitude.

Where the evidence splits

Antipsychotics and transition at 6 months: a 4-RCT meta-analysis found no effect (OR 0.63, 95% CI 0.31–1.27). Another review states that both studies it examined found low-dose antipsychotics reduced transition at 6 months. The sources on this page do not explain the split. The first is a pooled estimate across 4 RCTs. The second counts "both studies" without giving doses, comparators or sample sizes.

Baseline antipsychotic exposure and transition: the observational finding is higher transition in exposed people (29.9% vs 17.2%). The RCT findings show either no effect or a short-lived reduction. The review reporting the RCTs says the observational finding conflicts with them. The sources do not settle whether baseline exposure marks more severe cases or contributes to risk. One source lists this as an open mechanistic question.

Omega-3 and transition: a guideline-based statement says omega-3 "may aid" in delaying or preventing conversion. The 4-RCT meta-analysis found no effect at any timepoint. The guideline statement comes with no primary evidence in the source, and the sources do not say why the two differ.

Antipsychotics and attenuated symptoms: one review reports efficacy in acute management of attenuated psychotic symptoms. Another reports no robust evidence of superiority to needs-based care for reducing attenuated positive symptoms. The second names its comparator, needs-based care. The first does not name one, so the sources do not show whether the two measure the same contrast.

Thresholds and dose-response

No threshold established in the current sources.

Open empirical questions

• Whether baseline antipsychotic exposure raises transition risk or marks higher-risk people. Baseline severity has not been controlled in the sources here.
• Whether the 6-month reduction seen with low-dose antipsychotics and with CBT plus risperidone reflects symptom masking or a true delay in transition.
• Whether the lower transition rates seen with monotherapy or low doses hold when dose is assigned prospectively and not adjusted to response.
• What the long-term functional and quality-of-life outcomes of antipsychotic or omega-3 treatment in CHR-P are, and how often adverse effects occur in young CHR-P populations.