Deficits in relational memory — the part of memory that forms contextual relationships between individual items in daily life — appear to be common in the early stages of psychosis, according to study results published in Schizophrenia Research report.
A total of 89 patients in the early stage of psychosis (schizophreniform disorder [n=59], schizophrenia [n=23], schizoaffective disorder [n=4], and brief psychotic disorder [n=3]) were included in the study. At the time of enrollment, the average duration of psychosis was 7 months, with a range between shorter than 1 month to no longer than 24 months. Patients were compared with a group of healthy controls (n=84).
During a face-scene pairs task, the investigators examined eye movements to assess relational memory in all patients. The training task displayed 36 background face-scene pairs and patients were asked to remember which face matched with each background.
Test trials included scenes that were overlaid with 3 equally familiar faces, and investigators instructed patients to recall the matched face. The match trials consisted of 1 of the 3 faces previously paired with a background scene. Nonmatch trials consisted of no faces matching the scene. A direct measure of relational memory used in the trials was forced-choice explicit recognition.
During the match trials, healthy controls spent almost 2 seconds longer viewing the matching face compared with patients with early psychosis (7.7±1.5 seconds vs 6.0±2.2 seconds, respectively; face type by group interaction, F1171 = 282.43, P <.001). Healthy controls also demonstrated rapid preferential viewing of the matching face during these trials (250-500 millisecond time bin, t83 = 1.99; P =.05, Bonferroni corrected). Conversely, patients with early psychosis demonstrated longer preferential viewing of the match face (1000 to 1250 millisecond time bin, t88 = 3.80; P <.001, Bonferroni corrected).
In addition, healthy controls more accurately identified previously seen face-scene pairs than patients in early psychosis (90% vs 72%, respectively; F1168 = 22.21, r2 = 0.12; P <.001). Healthy controls also more accurately rejected untrained face-scene pairings (82% vs 48%; F1168 = 49.13, r2 = 0.23; P <.001; d’: healthy control = 0.89; early psychosis = −0.77; F1168 = 43.29, r2 = 0.21; P <.001).
Study limitations were the small sample sizes, as well as the inclusion of patients who were mostly treated with antipsychotic medications.
Findings from this study suggest that “relational memory deficits using eye movements as an implicit measure of relational memory … may be translated to studies in animals and non-verbal populations.”
Avery SN, Armstrong K, Blackford JU, et al. Impaired relational memory in the early stage of psychosis [published online August 8, 2019]. Schizophr Res. doi:10.1016/j.schres.2019.07.060