Divergent effects of healthy ageing on semantic knowledge and control: Evidence from novel comparisons with semantically impaired patients

Effective use of semantic knowledge requires a set of conceptual representations and control processes which ensure that currently relevant aspects of this knowledge are retrieved and selected. It is well-established that levels of semantic knowledge increase across the lifespan. However, the effects of ageing on semantic control processes have not been assessed. I addressed this issue by comparing the performance profiles of young and older people on a verbal comprehension test. Two sets of variables were used to predict accuracy and RT in each group: (1) the psycholinguistic properties of words probed in each trial and (2) the performance on each trial by two groups of semantically impaired neuropsychological patients. Young people demonstrated poor performance for low-frequency and abstract words, suggesting that they had difficulty processing words with intrinsically weak semantic representations. Indeed, performance in this group was strongly predicted by the performance of patients with semantic dementia, who suffer from degradation of semantic knowledge. In contrast, older adults performed poorly on trials where the target semantic relationship was weak and distractor relationships strong – conditions which require high levels of controlled processing. Their performance was not predicted by the performance of semantic dementia patients, but was predicted by the performance of patients with semantic control deficits. These findings indicate that the effects of ageing on semantic cognition are more complex than has previously been assumed. While older people have larger stores of knowledge than young people, they appear to be less skilled at exercising control over the activation of this knowledge.     

Determinants and Predictive Value of Clinician Assessment of Short‐Term Suicide Risk

We examine the interrelations among clinicians' judgment of patients' suicide risk, clinicians' emotional responses, and standard risk factors in the short‐term prediction of suicidal thoughts and behaviors. Psychiatric outpatients (n = 153) with a lifetime history of suicide ideation/attempt and their treating clinicians (n = 67) were evaluated at intake. Clinicians completed a standard suicide risk instrument (modified SAD PERSONS scale), a 10‐point Likert scale assessment of judgment of patient suicide risk (Clinician Prediction Scale), and a measure of their emotional responses to the patient (Therapist Response Questionnaire‐Suicide Form). The Columbia Suicide Severity Rating Scale and the Beck Scale for Suicide Ideation were administered at a one‐month follow‐up assessment (n = 114, 74.5%). Clinician judgment of risk significantly predicted suicidal thoughts and behaviors at follow‐up. Both the standard suicide risk instrument and clinician emotional responses contributed independently to the clinician assessment of risk, which, in turn, mediated their relationships with suicidal thoughts and behaviors. Our findings validate the importance of clinical judgment in assessing suicide risk. Clinical judgment appears to be informed both by concrete risk factors and clinicians' emotional responses to suicidal patients, highlighting emotional awareness as a promising area for research and training.