Speech Illusions in People at Clinical High Risk for Psychosis Linked to Clinical Outcome

Abstract

Background and hypothesis: Around 20% of people at clinical high risk (CHR) for psychosis later develop a psychotic disorder, but it is difficult to predict who this will be. We assessed the incidence of hearing speech (termed speech illusions [SIs]) in noise in CHR participants and examined whether this was associated with adverse clinical outcomes.

Study design: At baseline, 344 CHR participants and 67 healthy controls were presented with a computerized white noise task and asked whether they heard speech, and whether speech was neutral, affective, or whether they were uncertain about its valence. After 2 years, we assessed whether participants transitioned to psychosis, or remitted from the CHR state, and their functioning.

Study results: CHR participants had a lower sensitivity to the task. Logistic regression revealed that a bias towards hearing targets in stimuli was associated with remission status (OR = 0.21, P = 042). Conversely, hearing SIs with uncertain valence at baseline was associated with reduced likelihood of remission (OR = 7.72. P = .007). When we assessed only participants who did not take antipsychotic medication at baseline, the association between hearing SIs with uncertain valence at baseline and remission likelihood remained (OR = 7.61, P = .043) and this variable was additionally associated with a greater likelihood of transition to psychosis (OR = 5.34, P = .029).

Conclusions: In CHR individuals, a tendency to hear speech in noise, and uncertainty about the affective valence of this speech, is associated with adverse outcomes. This task could be used in a battery of cognitive markers to stratify CHR participants according to subsequent outcomes.

Keywords: remission; signal-detection; transition; uncertainty; white noise task.

Fig. 1.

The white noise task. Participants were presented with one of three conditions whilst wearing earphones: (1) white noise only, (2) white noise plus clearly audible neutral speech, (3) white noise plus barely audible neutral speech and required to verbally endorse one of five possible responses per trial: (1) no speech heard; (2) heard speech saying something neutral; (3) heard speech saying something positive; (4) heard speech saying something negative; (5) heard speech, but uncertain if it was positive, negative, or neutral. A response of 2,3,4, or 5 during condition 1 (white noise only) was defined as a speech illusion.

Fig. 2.

Associations between performance on the white noise task and outcomes in CHR participants 2 years later, (A) including participants taking antipsychotic medication at baseline, and (B) excluding participants taking antipsychotic medication at baseline.