Demographic and clinical characteristics*
| Measure | Group† | Group comparison | |||
|---|---|---|---|---|---|
| High CD | Low CD | Healthy controls | F / t / χ2 | p value | |
| Demographic information | |||||
| Participants, n | 16 | 24 | 25 | ||
| Age, yr | 21.81 ± 3.17 | 23.71 ± 5.43 | 22.12 ± 3.54 | 1.237 | 0.30 |
| M/F, n | 13/3 | 18/6 | 14/11 | 3.51 | 0.17 |
| Exposure to antipsychotic medication, d | 9.75 ± 16.46 | 12.57 ± 12.42 | — | 0.609 | 0.55 |
| Duration of untreated illness, d | 357.29 ± 412.90 | 331.64 ± 619.81 | — | −0.136 | 0.89 |
| Total DDD of antipsychotics | 1.80 ± 1.99 | 1.99 ± 4.58 | — | −0.178 | 0.86 |
| Duration of exposure to antipsychotics, d | 3.87 ± 3.78 | 2.19 ± 2.97 | — | 2.210 | 0.15 |
| Diagnosis of schizophrenia/other psychosis | 11/5 | 20/4 | — | 1.17 | 0.28 |
| Clinical and cognitive assessments | |||||
| PANSS-8 scores‡ | |||||
| Conceptual disorganization (P2)§ | 4.69 ± 0.79 | 1.63 ± 0.87 | — | 30.09 | < 0.001 |
| Lack of spontaneity and flow of conversation (N6)§ | 2.06 ± 1.44 | 2.13 ± 1.33 | — | 0.044 | 0.84 |
| Total positive component (P1 + P3 + G9)§ | 14.56 ± 2.99 | 12.67 ± 2.35 | — | 4.018 | 0.05 |
| Blunted affect and social withdrawal (N1 + N4)§ | 4.56 ± 3.41 | 5.58 ± 3.12 | — | 1.710 | 0.19 |
| SOFAS score | 33.79 ± 10.51 | 42.26 ± 13.60 | — | 4.966 | 0.032 |
| Modified DSST score | 51.94 ± 15.10 | 53.29 ± 13.40 | 68.74 ± 11.09 | 11.667 | < 0.001¶ |
| Metabolic assessments¶ | |||||
| Glutamate, mM | 6.57 ± 0.75 | 6.86 ± 1.45 | 6.69 ± 0.81 | 0.267 | 0.77 |
| Glutathione, mM | 1.83 ± 0.38 | 1.61 ± 0.36 | 1.48 ± 0.25 | 3.894 | 0.027** |
| Glutamate:glutathione | 3.69 ± 0.59 | 4.36 ± 0.86 | 4.58 ± 0.47 | 5.977 | 0.005** |
| CRLB glutamate | 3.67 ± 1.39 | 3.68 ± 1.03 | 3.24 ± 0.99 | 0.931 | 0.40 |
| CRLB glutathione | 9.85 ± 3.83 | 11.18 ± 4.02 | 10.59 ± 4.36 | 0.383 | 0.68 |
CD = conceptual disorganization; CRLB = Cramér-Rao lower bound; DDD = defined daily dose; DSST = digit symbol substitution test; MRS = magnetic resonance spectroscopy; PANSS-8 = 8-item Positive and Negative Syndrome Scale; SOFAS = Social and Occupational Functioning Assessment Scale.
↵* Participants included in the final analysis. Number of participants with MRS data: healthy controls = 18, high CD = 11, low CD = 21.
↵† Values are presented as mean ± standard deviation, unless otherwise indicated.
↵‡ Lack of spontaneity and flow of conversation (N6) means a participant’s lack of initiative, spontaneous and fluent conversation.
↵§ Kruskal–Wallis H test.
↵¶ High CD = low CD < healthy controls.
↵** HIgh CD > low CD = healthy controls.