Identifying suicide ideation in mental health application posts: A random forest algorithm.

The growing use of digitized mental health applications requires new reliable early screening tools to identify user suicide risk. We used a lexicon-based random forest machine learning algorithm to predict suicide ideation scores from 714 online community text posts from December 2019 to April 2020. We validated predicted scores against expert-rated suicide ideation scores. The algorithm-predicted scores offered high validity and a low error rate and correctly identified 95% of expert-rated high-risk suicide ideation posts. Our findings highlight a potential new method to detect suicidal ideation of digital mental health application users.

An Open Trial of the Effectiveness, Program Usage, and User Experience of Internet-based Cognitive Behavioural Therapy for Mixed Anxiety and Depression for Healthcare Workers on Disability Leave.

OBJECTIVE: An open trial of an internet-based Cognitive Behavioural Therapy (iCBT) program for healthcare workers was conducted. METHODS: Healthcare workers on disability leave who used the iCBT program were assessed on: self-reported depression and anxiety symptoms using the Depression Anxiety Stress Scales-21; and, program usage. Healthcare workers' experience of using iCBT was evaluated in a separate survey. RESULTS: Of the 497 healthcare workers referred to the iCBT program, 51% logged in, 25% logged in more than once, and 12% logged in more than once and completed at least two assessments. For the latter group, self-reported depression and anxiety symptoms significantly decreased from the first assessment. CONCLUSIONS: This iCBT program was perceived to be of benefit to healthcare workers, with program usage and effectiveness that was similar to what has been previously reported for unguided iCBT.

The perception of empty and filled time intervals by rats.

In experiment 1, rats were trained in a within-subjects design to discriminate durations of a filled interval, and durations of an empty interval (an unfilled interval marked at the beginning and end by a 500 ms tone). Training and psychophysical testing was conducted with three sets of anchor durations. Rats made more long responses for filled than for empty intervals at signal durations greater than the geometric mean. In experiment 2, group same was trained similarly to the rats in experiment 1 with the ambient conditions (houselight illumination) remaining the same during the inter-trial interval and the empty intervals. Group different was trained with the houselight turned off during empty and filled intervals. The similarity of ambient conditions during the inter-trial interval and the empty intervals did not significantly affect timing. Filled intervals were timed more precisely and they were perceived as longer than empty intervals of the same duration. The psychophysical functions superimposed across anchor duration sets. These results are the first clear evidence of a filled interval illusion in rats, and they suggest that this difference may reflect a clock rate effect (greater for filled intervals) rather than a switch latency effect (slower for empty intervals).

The perception of empty and filled time intervals by rats.

In Experiment 1, rats were trained in a within-subjects design to discriminate durations of a filled interval, and durations of an empty interval (an unfilled interval marked at the beginning and end by a 500 ms tone). Training and psychophysical testing was conducted with three sets of anchor durations. Rats made more long responses for filled than for empty intervals at signal durations greater than the geometric mean. In Experiment 2, Group Same was trained similarly to the rats in Experiment 1 with the ambient conditions (house light illumination) remaining the same during the intertrial interval and the empty intervals. Group Different was trained with the house light turned off during empty and filled intervals. The similarity of ambient conditions during the intertrial interval and the empty intervals did not significantly affect timing. Filled intervals were timed more precisely and they were perceived as longer than empty intervals of the same duration. The psychophysical functions superimposed across anchor duration sets. These results are the first clear evidence of a filled interval illusion in rats, and they suggest that this difference may reflect a clock rate effect (greater for filled intervals) rather than a switch latency effect (slower for empty intervals).

The perception of empty and filled time intervals by pigeons.

Pigeons were trained in a within-subjects design to discriminate durations of a filled interval (2 s and 8 s of light) and durations of an empty interval (2 s and 8 s bound by two 500-ms light markers). Filled intervals required a response to one set of comparisons (e.g., blue vs. yellow), whereas empty intervals required a response to a different set of comparisons (e.g., red vs. green). Psychophysical testing indicated that empty intervals were judged to be longer than equivalent durations of a filled interval. This finding was replicated when the anchor durations used during training were changed to 1 s and 4s, or 4s and 16s. The difference between the point of subjective equality (PSE) for the empty intervals and the PSE for filled intervals increased as the magnitude of the anchor duration pairs increased. In addition, the difference limens (DL) for empty intervals were smaller than those for filled intervals, and they also increased as the magnitude of anchor duration pairs increased. An analysis of the Weber fractions (WF; i.e., DL/PSE) provided evidence for superimposition of the empty and filled timing functions across the different sets of anchor durations. These results suggest that the accumulation of subjective time was greater for empty intervals than for filled intervals. Within the framework of scalar timing theory, this difference in timing appeared to be the result of a clock rate difference rather than a switch latency difference.