Prevalence and clinical relevance of interview-assessed psychosis-risk symptoms in the young adult community

Background An efficient indicated prevention of psychotic disorders requires valid risk criteria that work in both clinical and community samples. Yet, ultra-high risk and basic symptom criteria were recently recommended for use in clinical samples only. Their use in the community was discouraged for lack of knowledge about their prevalence, clinical relevance and risk factors in non-clinical, community settings when validly assessed with the same instruments used in the clinic. Methods Using semi-structured telephone interviews with established psychosis-risk instruments, we studied the prevalence of psychosis-risk symptoms and criteria, their clinical relevance (using presence of a non-psychotic mental disorder or of functional deficits as proxy measures) and their risk factors in a random, representative young adult community sample (N=2683; age 16–40 years; response rate: 63.4%). Results The point-prevalence of psychosis-risk symptoms was 13.8%. As these mostly occurred too infrequent to meet frequency requirements of psychosis-risk criteria, only 2.4% of participants met psychosis-risk criteria. A stepwise relationship underlay the association of ultra-high risk and basic symptoms with proxy measures of clinical relevance, this being most significant when both occurred together. In line with models of their formation, basic symptoms were selectively associated with age, ultra-high risk symptoms with traumatic events and lifetime substance misuse. Conclusions Psychosis-risk criteria were uncommon, indicating little risk of falsely labelling individuals from the community at-risk for psychosis. Besides, both psychosis-risk symptoms and criteria seem to possess sufficient clinical relevance to warrant their broader attention in clinical practice, especially if ultra-high risk and basic symptoms occur together.

 disorganized communication (P5) and speech that is still comprehensible and responds to structuring in the interview  First occurrence or worsening (in terms of an increase in conviction / loss of insight and/or of an increased impact on behaviour) within the past 12 months.  At least weekly occurrence within past month.

Ultra-high risk criterion 'Brief Intermittent Psychotic Symptoms' (BIPS)
 At least any 1 of the above 5 items (P1-P5) with a SIPS score of '6', i.e. temporarily held with full conviction or with complete lack of insight  Psychotic level of intensity, i.e., a score of '6' was reached within past 3 months.  At least present for several minutes per day at a frequency of at least once per month. Basic symptom criterion 'Cognitive-Perceptive Basic Symptoms' (COPER)  At least any 1 of the following 10 basic symptoms:  thought interference (D9): Irrelevant, emotionally neutral thoughts with no special meaning and no association with the intended thought are intruding on and disturbing the young person's train of thought, without it being lost.  thought perseveration (C2): A kind of thought interference in that intruding emotionally neutral and irrelevant thoughts or images occur not just once but repeatedly.  thought pressure (D10): A self-reported 'chaos' of thoughts in that successively occurring thoughts are not linked by any common thread, and are completely unrelated to each other or to the young person's intended line of thought.  thought blockages (D15): Sudden interruption in the flow of thoughts, or experiences of the mind suddenly going blank, of a fading (slipping) of thoughts or of losing the thread of thoughts, with the original topic being recalled subsequently or lost completely.  disturbance of receptive speech (D11): A disturbance in the understanding of simple everyday words. When reading or listening to others, the young person struggles to comprehend the meaning of words, word sequences or sentences, even if the young person concentrates on the text or speech and has perceived it accurately.

 decreased ability to discriminate between ideas and perception, fantasy and true memories (B2):
A self-recognized difficulty in locating the source of an experience/memory (external vs. internal mental) that results in an inability to immediately distinguish between imaginations and perception, or pure fantasy and true memories.  unstable ideas of reference (B2): Subjective, subclinical experiences of self-reference for that no explanation outside own mental processes are sought, and that is immediately overcome.  derealisation (O8): A change in how one relates emotionally to the environment, which is experienced commonly as an estrangement and detachment from the visual world, or rarely as an increased emotional affinity for the environment.  visual perception disturbances (O4) (excl. blurred vision and hypersensitivity to light): Misperceptions of aspects of the visual field while the young person is fully aware of their true appearance and, therefore, attributes his or her misperception to a problem with eye sight or mental processes.  acoustic perception disturbances (O5) (excl. hypersensitivity to sounds/noises): Misperceptions of acoustic stimuli while the young person is fully aware of the true sound and, therefore, tends to attribute his or her misperception to a problem with hearing or mental processes.  First occurrence or significant increase in frequency ≥12 months ago  Occurrence of at least 'several times in a month or weekly' within the past 3 months, i.e. a SPI-A score of at least '3'.

Basic symptom criterion 'Cognitive Disturbances' (COGDIS)
 At least any 2 of the following 9 basic symptoms:  inability to divide attention (B1): A difficulty in dealing with demands that involve more than one sensory modality at a time and thus does not concern demands that would require quick switching of attention. Note: A general requirement of basic symptoms is their novelty, i.e., their report as a disruption in a person's "normal" self. Self-recognized aberrations in mental processes that have always been present in the same frequency, i.e., in a traitlike manner, can be rated in SPI-A (rating of "7") but are not accounted for as basic symptoms in the strict sense and, consequently, do not contribute to basic symptoms criteria. More in-depth definitions of basic symptoms as well as example statements of patients and example questions for their assessment are provided in the SPI-A, orderable at www.fioriti.it.

Definition of basic symptoms
Basic symptoms were conceptualised as the earliest primarily self-experienced psychopathological correlates of the physiological disturbances of information processing underlying the development of psychosis that develops on the basis of and partly in reaction to them (Schultze-Lutter et al. 2016). By 4/10 definition, basic symptoms differ from what patients' consider to be their 'normal' mental self, and thus, are distinct from trait-like schizotypy features considered as part of the 'normal' self (Schultze-Lutter, 2009). Furthermore, basic symptoms remain predominately private and are rarely observable to others, although patients' self-initiated coping strategies (including avoidance strategies and social withdrawal) in response to their basic symptoms may be observable, e.g., as negative symptoms.
Phenomenological differences between basic and ultra-high risk / schizotypal symptoms For their spontaneous, immediate recognition by patients as disturbances of their own (mental) processes, basic symptoms are also distinct from the symptoms that define the ultra-high risk criteria (i.e., attenuated psychotic symptoms (APS) or brief intermittent psychotic symptoms (BIPS)) and from frank psychotic symptoms, in which reality testing is disturbed at least to some degree. Within the basic symptoms concept, (attenuated) psychotic symptoms are considered to arise from basic symptoms when everyday situations and demands overstrain patients' already pathologically vulnerable information processing capacity. Thus, given the salutary environmental and personal conditions (e.g., a supportive social network; good social, problem solving, and coping skills; or high self-efficacy), basic symptoms can be counterbalanced as long as their number and/or severity do not overextend protective factors and patients' resilience (Schultze-Lutter, 2009; Schultze-Lutter, 2016). Basic symptoms are phenomenologically distinct from mental states that an individual would consider being his or her 'normal' self. Thus, the novelty of basic symptoms distinguishes them from the subtle long-standing disturbances that present as traits in those at genetic high-risk (Parnas & Carter, 2002;Jones, 2002). In addition, basic symptoms are phenomenologically distinct from APS, BIPS and frank psychotic symptoms because they are not necessarily observable by others in terms of odd thinking, disturbed speech, or formal thought disorder. BS are subtle and subjective, in the sense that they rarely affect observable speech, thought content or behaviour, unlike the more typical psychotic or schizotypal phenomena of magical thinking, ideas of reference, paranoid ideation, suspiciousness, delusions, and 'Ich-Störungen' (i.e., thought broadcasting; insertion, withdrawal, and delusion of alien control). Furthermore, they may be distinguished from negative symptoms in that they are not observable functional deficits (Parnas et al. 2005) but remain completely in the subjective world of the individual experiencing them. Commonly, BS are not a part of the definition of mental disorders, although basic symptoms that are not part of COGDIS or COPER can be reported in non-psychotic mental disorders (Klosterkötter et al. 1996).

Differences between ultra-high risk and schizotypal symptoms
In contrast to the basic symptoms criteria, the ultra-high risk criteria and symptoms were mainly modelled on the subthreshold psychotic-like experiences as defined by Chapman and colleagues (Chapman & Chapman, 1980)   international-standard-classification-of-education.aspx). Description of main categories: 2=lower secondary education; 3=upper secondary education; 5= short-cycle tertiary education, and 7=Master or equivalent. e in 1 st -or 2 nd -degree biological relatives; known as well as very likely main disorder, multiple relatives possible, maximum reported number of affected relatives was n=5 f "Other" includes frequent report of "burn-out" as well as of severe developmental and personality disorders, "unknown but very likely" includes reports of relatives who had received help for largely unspecified mental problems or were known in the family for mental problems associated with behavioral abnormalities / functional impairments  GoF: goodness-of-fit; APS: attenuated psychotic symptom; BIPS: brief intermittent psychotic symptom. Significant variables at a p-level of 5% in univariate analyses are displayed in Italics.