Table 2.
Findings.
| Study | Executive functions and language | Memory | Attention | Perceptuomotor functions | IQ | Notes |
|---|---|---|---|---|---|---|
| Barrett et al. (17) in Lewandowski et al. (8) | BD, SZ < HC, impaired on executive functioning and language by first episode SZ < BD < HC on response inhibition, verbal fluency and callosal functioning |
BD, SZ < HC, impaired in verbal and visual memory performances by first episode BD pt are reported to have intermediate results between the two groups |
No differences | BD and SZ pt disclosed lower premorbid and current IQ scores compared to HC BD > SZ in current IQ score |
SZ with “preserved” IQ = BD: similar “pattern” of deficits | |
| Brissos et al. (16) | BD, SZ < HC in stimulus inhibition, and information processing BD pt performed intermediately between SZ pt and HC although differences didn’t reach statistical significance |
No differences | SZ < BD, HC on simple automatic and attentional processing Attention deficits in SZ and BD pt persisted during the entire course of the disease including periods of euthymia |
BD, SZ < HC on perceptual-motor skills | Not assessed | Although not significantly, BD pt performed intermediately between pt with SZ and HC |
| Brissos et al. (20) | SZ < BD < HC on mental control, processing speed, executive functions (only quantitative, not qualitative differences) | SZ, BD < HC on verbal memory function | SZ > BD HPS+, HPS−, HC in slowness and perseveration in incongruent tasks is interpreted as a proxy of deficient inhibitory control, strongly related with poor selective attention | Not assessed | Controlled for educational level, not IQ | BD HPS+ was not associated with more severe cognitive impairment during euthymia |
| Gogos et al. (24) | SZ, BD < HC on language | SZ < BD < HC on immediate memory/learning SZ < BD, HC on delayed memory SZ < BD, HC on visuo-spatial and delayed memory |
SZ < HC on attention SZ = BD on attention Attention deficits in SZ and BD patients persisted during the entire course of the disease including periods of euthymia. Similar results found using different tests that required keeping attention focused for an extended amount of time |
Not assessed | Matched for IQ | SZ < BD, HC on overall cognitive functioning |
| Joshua et al. (18) | SZ < BD, control on overall HSCT performance (overall executive dysfunction) SZ > HC on response latency (BD scored in the middle with ns. differences with either SZ or control) SZ > HC on response errors (BD scored in the middle with ns. differences with either SZ or control) SZ > BD, HC on semantically related errors |
Not assessed | Not assessed | Not assessed | Controlled for IQ | SZ group was significantly impaired on all measures of executive functioning BD group did not differ, from HC |
| Rossell and Batty (25) | SZ < BD, HC on the semantic retrieval (more executive task) SZ = BD = HC on word comprehension across grammatical categories (depend on executive regulation) |
SZ, BD < HC on semantic recognition, both clinical groups presented similar performance with difficulties in identifying the correct word meaning in the presence of alternatives | Not assessed | Not assessed | BD and HC matched for IQ, and different from SZ Controlled for IQ | SZ and BD show a shortfall in ability to organize and categorize word meanings |
| Sanchez-Morla et al. (23) | SZ, BD < HC on all tasks SZ < BD: executive control, verbal working memory SZ = BD on executive control, planning and problem solving, and semantic fluency | SZ < BD < HC in immediate and delayed visual memory SZ vs. BD: mixed results in Verbal Memory Tests |
SZ, BD < HC Attention deficits in SZ and BD pt persisted during the entire course of the disease including during periods of euthymia | Not assessed | SZ, BD < HC Controlled for IQ | Duration of illness correlated with executive, verbal memory and visual memory functioning in BD BD with history of psychosis = BD without history psychosis |
| Simonsen et al. (19) | SZ, SZA, BD HPS+,<BD, HPS−, HC on set shifting verbal fluency BD HPS− = HC on all neurocognitive subscores, apart from digit symbol where they performed poorer |
SZ, SZA, BD with psychosis<BD, HC on verbal learning and memory BD pt are reported to have intermediate results between the two groups |
Not assessed | Both psychotic and non-psychotic pt reported lower perceptuomotor functions as compared to HC. No significant differences were shown between them. Other pt with a history of psychosis (SZ, SZA) performed poorly than HC on measures of processing speeding. In particular, SZ pt showed lower Dygit Symbol Test – WAIS-III scores as compared to psychotic BD pt | SZ < BD, HC Controlled for IQ | All patients with a history of psychosis performed poorly on all measures |
| Wobrock et al. (22) | SZ chronic and first episode<HC on speed, verbal fluency, and verbal working memory With regard to cognitive flexibility, SZ pt showed more perseverative responses with poorer WCST scores as compared to BD pt and HC |
Both first episode and chronic SZ pt have decreased verbal learning and memory performances as compared to HC. BD pt are reported to have intermediate results between the two groups | SZ pt chronic and first episode<HC on attention | SZ pt chronic and first episode<HC on psychomotor performance | SZ pt showed significant poorer results compared to HC | SZ pt overall showed a poorer performance than BD and HC |
| Zanelli et al. (28) | SZ < BD on measures of vocabulary and comprehension, digit symbol, letter-number span, and block design BD < HC on measures of category fluency SZ < HC on the Letter-Number Span Test DP < HC on measures of verbal learning and category fluency, and on the TMT-B OP < HC on verbal learning BD < HC on category fluency |
BD < HC on measures of delayed verbal memory | SZ < BD < HC in overall measures | Not assessed | SZ pt showed significant poorer results compared to HC in all examined studies Similar pattern between clinical groups were reported with regard to current IQ | SZ acute and chronic showed poorer performance than the rest |
HC, healthy controls; SZ, schizophrenia; BD, bipolar disorder; SZA, schizoaffective disorder; SZF, schizophreniform disorder; Pt, patients; NART, National Adult Reading Test; SDMT, Symbol Digit Modalities Test; TMT-A, Trail Making Test part A; TMT-B, Trail Making Test part B; HDRS, Hamilton Depressive Rating Scale; YMRS, Young Mania Rating Scale; SCWT, Stroop Color-Write Test; CPT, Continuous Performance Test; WAIS-R, Wechsler Adult Intelligence Scale Revised; WCST, Wisconsin Card Sorting Test.