Timing, Distribution, and Relationship Between Nonpsychotic and Subthreshold Psychotic Symptoms Prior to Emergence of a First Episode of Psychosis

Abstract

Prospective population studies suggest that psychotic syndromes may be an emergent phenomenon-a function of severity and complexity of more common mental health presentations and their nonpsychotic symptoms. Examining the relationship between nonpsychotic and subthreshold psychotic symptoms in individuals who later developed the ultimate outcome of interest, a first episode of psychosis (FEP), could provide valuable data to support or refute this conceptualization of how psychosis develops. We therefore conducted a detailed follow-back study consisting of semistructured interviews with 430 patients and families supplemented by chart reviews in a catchment-based sample of affective and nonaffective FEP. The onset and sequence of 27 pre-onset nonpsychotic (NPS) or subthreshold psychotic (STPS) symptoms was systematically characterized. Differences in proportions were analyzed with z-tests, and correlations were assessed with negative binomial regressions. Both the first psychiatric symptom (86.24% NPS) and the first prodromal symptom (66.51% NPS) were more likely to be NPS than STPS. Patients reporting pre-onset STPS had proportionally more of each NPS than did those without pre-onset STPS. Finally, there was a strong positive correlation between NPS counts (reflecting complexity) and STPS counts (β = 0.34, 95% CI [0.31, 0.38], P < 2 e-16). Prior to a FEP, NPS precede STPS, and greater complexity of NPS is associated with the presence and frequency of STPS. These findings complement recent arguments that the emergence of psychotic illness is better conceptualized as part of a continuum-with implications for understanding pluripotential developmental trajectories and strengthening early intervention paradigms.

Keywords: at-risk mental state; first-episode psychosis; psychopathology; psychosis; subthreshold psychotic symptoms; trajectory.

Figure 1.

Timing of symptom onset. Histograms of distribution for first symptom type for a) outpost syndrome b) prodrome c) outpost if first prodromal symptom was STPS d) outpost if first prodromal symptom was NPS.

Figure 2.

Radial arm plot for symptom distribution. Radial arm plot for STPSa group and STPSp group for STPS (A = suspiciousness, B = odd ideas of reference, C = odd behavior, D = Unusual perceptual experienced, E = disorganized speech, F = inappropriate affect, G = hallucinations, H = delusions, I = passivity) and NPS (1 = depression, 2 = anxiety, 3 = impaired role functioning, 4 = social withdrawal, 5 = impaired concentration, 6 = sleep disturbance, 7 = decreased energy, 8 = irritability, 9 = change in weight, 10 = restlessness, 11 = blunted affect, 12 = memory problems, 13 = elated mood, 14 = poor grooming, 15 = self harm, 16 = obsessive compulsive, 17 = extrapyramidal symptoms, 18 = catatonia).

Figure 3.

Radial arm plot for symptom distribution. Radial arm plot for STPSa group and STPSp group for STPS (A = suspiciousness, B = odd ideas of reference, C = odd behavior, D = Unusual perceptual experienced, E = disorganized speech, F = inappropriate affect, G = hallucinations, H = delusions, I = passivity) and NPS (1 = depression, 2 = anxiety, 3 = impaired role functioning, 4 = social withdrawal, 5 = impaired concentration, 6 = sleep disturbance, 7 = decreased energy, 8 = irritability, 9 = change in weight, 10 = restlessness, 11 = blunted affect, 12 = memory problems, 13 = elated mood, 14 = poor grooming, 15 = self harm, 16 = obsessive compulsive, 17 = extrapyramidal symptoms, 18 = catatonia).

Figure 4.

Relationship among symptoms. a) Binned histogram with count of NPS on x-axis (8+ combined to protect anonymity of participants) and proportion of sample reporting each NPS on the y-axis. Total sample for each NPS count indicated at the top of each bar. Colors represent binned counts of STPS. b) Graph representing NBR for the total sample. Dashed line indicates standardized slope for STPSp sample for comparison.