You could also look into CAPE

http://www.ncbi.nlm.nih.gov/pubmed/16774662

Yep: http://schizophreniabulletin.oxfordjournals.org/content/37/2/362.short

I suggest you to contact Prof. Jacek Wciórka and ask about his paper:

Self-rating scales in schizophrenia: assessment of the reliability of the Paranoid-Depressive Scale (PD-S) Frankfurt Self-feeling Scale (FBS). and two visual analogy scales

You could also look into CAPE

http://www.ncbi.nlm.nih.gov/pubmed/16774662

I use the Colorado Symptom Index...

I would suggest the CAPE too (The Community Assessment of Psychic Experiences, Stefanis et al. 2002 Psychologial Mecicine). It is a self-reported questionnaire where individuals report how often (if anytime) they have experienced different psychotic symptoms (also termed psychotic experiences or psychotic-like experiences when referring to subclinical symptoms assessed in general populations). Also, individuals are requested to indicate how they feel when they experienced the symptom. It is a validated and widely used instrument to assess in non-clinical samples the occurrence and appraisal of experiencing psychotic symptoms such as hearing voices. Furthermore, the instrument includes a positive, negative and depressive dimensions of psychotic experiences and you can find it in different languages at http://cape42.homestead.com/

I have used in my research and people had no problems fill in it, the data you get is really useful.

Of note, schizotypy and psychotic experiences are two different approachs to the assessment of attenuated or subclinical psychosis. I would strongly recommend you this paper about this issue: THE CONTINUITY OF PSYCHOTIC EXPERIENCES IN THE GENERAL POPULATION by Johns and Van Os, published in Clinical Psychology Review in 2001.

Good luck!

There are multiple options, for example the one Martin suggested, which is a useful for screening in young adolescent populations. Another one is the Community Assessment of Psychic Experiences (CAPE) which is freely available in many languages online (http://cape42.homestead.com/) and has mostly been used in large population samples. The CAPE is partially derived from another questionnaire called the PDI, which focuses on positive symptoms. Then there is also the prodromal questionnaire (PQ). Both CAPE and PQ have also been abbreviated for screening purposes. And there are many more, depending on the language, population and purpose of your study.

Or, also suitable for the general population (i.e. psychotic-like experiences) see attached article which validates the Dutch version of the Persecutory Ideation Questionnaire, also available in English of course.

Article Psychometric evaluation of the Dutch Persecutory Ideation Qu...

If you want to focus specifically on auditory hallucinations and delusions, the Psychotic Symptoms Rating Scale (PSYRATS) is an excellent and well-used questionnaire: Haddock et al., 1999. Psychological Medicine / Volume 29 / Issue 04 / July 1999, pp 879-889

There is no doi listed, but here is the link: http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=26371&fulltextType=RA&fileId=S0033291799008661

Some items in many tools try to ask about psychotic experiences, but the psychotic symptoms may be not recognized symptomatic and self-reported (same is true for interviewing unfortunately),

The following really recent links may be helpful? i.e.: http://www.ncbi.nlm.nih.gov/pubmed/24062593 and http://www.ncbi.nlm.nih.gov/pubmed/23182728

The PSYRATS is a good option, but is limited only to auditory verbal hallucinations and delusions. A good option for delusions is the Peter's et al Delusions Inventory in a recent brief version of 21 items (published in Schizophrenia Bulletin in 2004: PMID: 15954204 [PubMed - indexed for MEDLINE) Likewise, the CAPE is a good instrument, with adequate psychometric properties.

+1 for CAPE

the Eppendorf Schizophrenia Inventory (ESI)

the Revised Behavior and Symptom Identification Scale (BASIS-R). The BASIS-R is a 24-item self-report instrument with six scales: psychosis, depression/functioning, interpersonal problems, alcohol/drug use, self-harm, and emotional lability.

the Symptom Checklist-90-Revised (SCL-90-R). The SCL-90-R is a 90-item self-assessment tool that measures psychoticism and paranoid ideation in addition to seven other symptom scales.

the Brief Symptom Inventory (BSI). The BSI is a 53-item self-administered scale developed from the SCL-90-R. The BSI has good psychometric properties and is an acceptable brief alternative to the SCL-90-R.

Within the CAPE you can also further divide the positive scale into four subtypes of psychotic-like experiences which include bizarre experiences (6 items), perceptual abnormalities (3 items), persecutory ideation (7 items), and magical thinking (4 items) (Yung et al., 2009) [Yung, A.R., Nelson, B., Baker, K., Buckby, J.A., Baksheev, G., Cosgrave, E.M., 2009. Psychotic-like experiences in a community sample of adolescents: implications for the continuum model of psychosis and prediction of schizophrenia. The Australian and New Zealand journal of psychiatry 43, 118-128.]

Tha Cape is a good choice. The PSYRATS is actually a structered interview. We use as a screen the PQ-16. It is only 16 items and will screen out those at risk for developing a first episode or wh are already psychotic. Takes 2 minutes.

What about the Psychosis Screening Qustionnaire?

BASIS R (Behaviour and Symptom Identification Scale - revised) is a self report instrument with six scales and on these six scales is on psychosis.

The CAPE and PQ-16 (Ising et al. Schizoph Bulletin 2012) are a good choice if you want a general screen re. psychotic symptoms/risk for psychosis; obviously the questionnaires would need to be followed by a face-to-face interview in case of positive answers.

It is an interesting measurement question when you are asking to take self report responses and identify dramatic distortions is perception and thinking. I'm sure there are measures that pass muster for traditional research reliability and validity but I would be somewhat skeptical of their clinical meaningfulness. Further, many people with psychotic symptoms don't trust others so the concept of self report provides additional challenges (blind trust).

Standardized self-report inventories can be very helpful as part of the assessment, of course, but in the case of psychosis (and other clinical issues!) a self-report inventory could not take the place of the clinical interview. Some of the questions are: Does the person show flat affect? Does the person use neologisms? Do their reported hallucinations occur in clear consciousness, or could they represent normal variants such as hypnagogic or hypnopompic imagery? Does the person show disorganized speech? Has their general functioning deteriorated from an earlier, higher level for a significant period of time? All of these questions could be of diagnostic significance, but it might be difficult to design self-report items to capture these issues.

There are a class of individuals with psychotic episodes or such history who actually report quite accurately and honestly on self-report questionnaires. If therapeutic alliance is good, patients feel motivated to give appropriate responses. Such motivations are yet unexplored in literature. Insight and trust among schizophrenics are not the only factors for the distortions on self-report scales. Some of the obvious biases are quite common among all sorts of individuals. However, individuals with few cognitive deficits and lesser intensities of persecutory ideas (like in brief/acute episodes or first-episodes) generally would provide appropriate responses if they are giving assessments as part of therapy. If a random person, like in first meeting or a trainee, would take assessments then responses would be distorted. So, if some care is taken, good quality responses are not difficult to get. But again such a thing is possible with any kind of patient, not just psychotics. That is why the notion and common perception about relevance of self-report tools with psychotics needs to be changed.