The prevalence, incidence, and admission rate of diagnosed schizophrenia spectrum disorders in Korea, 2008-2017: A nationwide population-based study using claims big data analysis.

This study estimated the prevalence and incidence rate of schizophrenia, schizotypal, and delusional disorders (SSDD) in Korea from 2008 to 2017 and analyzed the hospital admission rate, re-admission rate, and hospitalization period. It used the Korean nationwide National Health Insurance Service claims database. SSDD patients who had at least one visit to Korea's primary, secondary, or tertiary referral hospitals with a diagnosis of SSDD, according to the International Classification of Diseases, 10th Revision (ICD-10), were identified as SSDD cases if coded as F20-F29. Data were analyzed using frequency statistics. Results showed that the 12-month prevalence rate of SSDD increased steadily from 0.40% in 2008 to 0.45% in 2017. Analysis of the three-year cumulative prevalence rate of SSDD showed an increase from 0.51% in 2011 to 0.54% in 2017. In 2017, the five-year cumulative prevalence rate was 0.61%, and the 10-year cumulative prevalence rate was 0.75%. The hospital admission rate among SSDD patients decreased from 2008 (30.04%) to 2017 (28.53%). The incidence of SSDD was 0.05% and no yearly change was observed. The proportion of SSDD inpatients whose first hospital visit resulted in immediate hospitalization was 22.4% in 2017. Epidemiological indicators such as prevalence, incidence, and hospitalization rate play an important role in planning social and financial resource allocation. Therefore, efforts to produce more accurate epidemiological indicators are very important and this study's findings could have a significant social impact.

Cannabis and psychometrically-defined schizotypy: use, problems and treatment considerations.

Cannabis use is associated with onset of psychosis in individuals vulnerable for developing schizophrenia-spectrum disorders. The present study addressed three knowledge gaps pertaining to this issue: 1) clarifying the incidence of cannabis use in schizotypal individuals, 2) examining how cannabis use is related to psychosocial and physiological problems in schizotypy and interest in treatment, and 3) examining how cannabis use is associated with positive, negative and disorganization features of schizotypy. Scores from a measure of schizotypal traits were used to trichotomize 1665 young adults into schizotypy (top 5% of scorers), non-schizotypy (bottom 50% of scorers) and "unconventional" (scorers within the 50th to 85th percentile) groups. Nearly a quarter of the schizotypy group endorsed cannabis use at least weekly, a rate nearly two to four times that of the other groups. The schizotypy group also reported a much greater frequency of cannabis-related problems compared to the other groups. Despite this, interest in treatment for cannabis use in the schizotypy group was not elevated. Interestingly, 85% of individuals in the schizotypy group reported interest in psychological/psychiatric treatment more generally. Cannabis use was not associated with abnormal patterns of positive or disorganized schizotypy traits in the schizotypy group relative to the other groups. However, cannabis use was associated with lower severity of negative traits. Implications of these results are discussed.

[Decisions in conditional situation and theory of mind in schizotypy]. / Décisions en situation probabiliste et théorie de l'esprit dans la schizotypie.

INTRODUCTION: Theory of mind (ToM) is defined as a capacity to infer mental states, intentions, and emotions in others. Two principal theories in the field of cognitive psychology have tried to explain mechanisms underlying this capacity. Theory-theory hypothesizes that people interpret cues from others in social interactions with a folk psychology composed of data about social human behavior. In contrast, Simulation-Theory proposes a capacity to take different perspectives and mentally simulate others' behavior. As a result, one could guess a person's intention or emotion by comparison with his state of mind when he/she behaves in the same way. BACKGROUND: Difficulties in ToM have been frequently observed in schizotypal subjects and subjects with schizophrenia. Some authors have proposed that this impairment could lead to persecution delusions or be linked with disorganized thought. A tendency to make choices with few cues in conditional situation has also been observed in both populations. When they are asked to make a decision about cues they can choose to see or not, schizotypal subjects and patients with schizophrenia tend to make up their mind after significantly less cues than control subjects. This tendency has been called "jump to conclusion". OBJECTIVE: Our study tests the correlation between low performances at a ToM task and a tendency to jump to conclusion in conditional situation. PARTICIPANTS: We tested this hypothesis with 25 participants scoring high on a social anhedonia scale (J Abnorm Psychol 85 (1976) 374-382), one of the main characteristics of schizotypy, and with 20 control participants. Participants were students with a mean age of 20. We included in the experimental group, subjects with a score on social anhedonia scale superior to 17 for females and 19 for males, and seven for control participants (modal score). METHODS: We used "jar and beads", a conditional reasoning task. Two jars are presented to a participant: a white one containing 85% of white beads and 15% of black beads, and a black one filled with the opposite ratio. The participant has to decide from which jar comes successive beads shown to him. Dependent measure is the number of beads seen before decision. ToM task is an adaptation from (Schizophr Res 17 (1995) 5-13). Twenty short interactions between two characters are read to a participant. For example: John has a phone call with a friend for one hour. He says: "My mother ought to call me in a few minutes". QUESTION: What does John really mean? Cue: John adds: "I could call you tomorrow morning". QUESTION: What does John want to do? RESULTS: Results show significantly lower performances at the ToM task in experimental than in control participants (52.36 (S.D., 6.73) vs. 59.05 (S.D., 1.60); t, 4.33; p<0.001; maximum possible, 60). The experimental group asked for significantly less cues to conclude in the conditional situation (2.22-S.D., 1.29). Mean number of beads asked for in the control group was 3.05 (S.D., 1.30) and t, 2.13; p<0.05. There was no correlation between performances at conditional reasoning task and ToM task. We observed this absence of correlation in all of the participants and in the experimental and control groups separately. DISCUSSION: Absence of relationship between performances in both tasks may be attributed to a discrepancy between experimental and ecological contexts for conditional reasoning task. During interpersonal relationships, search for cues in order to make a decision about others' intentions and mental states represents a real cost in terms of energy and time. These costs are absent in the "jar and beads situation". Moreover, people with social anhedonia may attribute a special value of quickly understanding personal interactions. This conditional reasoning task does not imply this parameter. CONCLUSION: Ecological decision in conditional reasoning tasks could be approached by adding a system of points to spend, asking for more cues, or to earn, finally finding the correct answer. Decision would then depend on the ratio between possible gains, by guessing or not the correct answer, and the cost of searching for more cues before making a decision.

Scores for schizotypy and five-factor model of a sample of distant healers: a preliminary study.

A preliminary study was conducted to evaluate the personality scores of 18 distant healers on the NEO-Five Factor Inventory and the Schizotypal Personality Questionnaire-Brief. These distant healers differed significantly in their schizotypic tendencies, both in comparison to normed scores and to a control group of 19 masseurs. Further differences were found on scales of Conscientiousness and Openness to experience.

Psychophysiological evidence of altered neural synchronization in cannabis use: relationship to schizotypy.

OBJECTIVE: Cannabis use may produce neurophysiological disturbances similar to those observed in schizophrenia, particularly in relation to altered neural synchronization. Therefore, the current experiment examined the effect of cannabis use on EEG neural synchronization using the auditory steady-state evoked potential. METHOD: Auditory steady-state evoked potentials were assessed using varying rates of stimulation (auditory click-trains of 20, 30, 40 Hz) in current cannabis users (N=17) and drug-naive comparison subjects (N=16). EEG spectral power and signal-to-noise ratio at each stimulation frequency were compared between groups. RESULTS: Cannabis users showed decreased EEG power and signal-to-noise ratio at the stimulation frequency of 20 Hz. In addition, current cannabis users demonstrated increased schizotypal personality characteristics as assessed with the Schizotypal Personality Questionnaire, which positively correlated with total years of cannabis use. Finally, within the cannabis group, 20-Hz power values were negatively correlated with Schizotypal Personality Questionnaire scores. CONCLUSIONS: These data provide evidence for neural synchronization and early-stage sensory processing deficits in cannabis use. This finding, along with the observed increased rates of schizotypy in cannabis users, adds support for a cannabinoid link to schizophrenia spectrum disorders.

[Schizotypal personality disorder--diagnosis and treatment]. / Schizotypische Persönlichkeitsstörung. Müde Patienten mit Esoterikerfahrung.

Schizotypal personality disorder is relatively common disorder, and is considered to be a mild form of schizophrenia. It is characterized by such "psychotic" symptoms as ideas of reference, odd or magical thinking, perceptual illusions and an inappropriate or flattened affect. In their contact with others, patients show odd expression and behavior. Since, numerous schizotypal symptoms can be treated successfully with atypical antipsychotic medication, the patient should be referred to a psychiatrist or neurologist. The mainstay of psychotherapy consists in crisis management, development of self-awareness of the problem, breaking down social isolation and general unspecific support in coping with daily problems.

Modulation of the startle response and startle laterality in relatives of schizophrenic patients and in subjects with schizotypal personality disorder: evidence of inhibitory deficits.

OBJECTIVE: Patients with schizophrenia spectrum disorders have been shown to have deficits in sensorimotor gating as assessed by prepulse inhibition of the startle response. The authors hypothesized that nonschizophrenic relatives of patients with schizophrenia would also have prepulse inhibition deficits, thereby reflecting a genetically transmitted susceptibility to sensorimotor gating deficits. METHOD: Twenty-five comparison subjects, 23 patients with schizophrenia, 34 relatives of the schizophrenic patients, and 11 subjects with schizotypal personality disorder were assessed in an acoustic startle paradigm. The eye-blink component of the startle response was assessed bilaterally by using electromyographic recordings of orbicularis oculi. RESULTS: The patients with schizophrenia, their relatives, and subjects with schizotypal personality disorder all had reduced prepulse inhibition relative to comparison subjects, and these deficits were more evident in measures of right eye-blink prepulse inhibition. Comparison subjects demonstrated greater right versus left eye-blink prepulse inhibition, whereas the probands, their relatives, and subjects with schizotypal personality disorder showed less asymmetry of prepulse inhibition. CONCLUSIONS: These data suggest a genetically transmitted deficit in prepulse inhibition (sensorimotor gating) in patients with schizophrenia spectrum disorders, including subjects with schizotypal personality disorder and relatives of patients with schizophrenia.