Selman,

I do not know this scale but an inventory that sounds like that (i.e. as list of symptoms) will rarely be appropriate for factor analysis. Lists of things are aggregate constructs and most often do not reflect a common factor model.

Best,

Holger

But it would be useful to conduct a FA on an extensive list of neurotic and psychotic symptoms and see how the psychopathology latent "space" looks like. This could be compared with classifications of mental disorders and linked criteria (referring to ICD-11 and DSM-5). Empirically supported categories will remain in these classifi ations, some of them would be revised and others refuted.

I doubt that factor models are appropriate as I wrote. A factor model suggests that the symptoms correlate due to the causal influence of the underlying singular "symptom-inducing process variable". This may be the case (years ago I discussed that in the following paper with regard to psychosomatic complaints (based on sensitization theory):

Steinmetz, H., & Schmidt, P. (2010). Subjective health and its relationship with working time variables and job stressors: Sequence or general factor model? Work & Stress, 24(2), 159-178. doi:10.1080/02678373.2010.489784

But the essential implication of a factor model is that of local independence, namely that the correlations are zero once the factor is taken into account. In the last years there was a substantial rise of research which doubts that and instead proposes network models that define diseases as networks of mutually reinforcing symptoms (e.g., instead of sadness and feeling lonely conceived as reflective indicators of some latent depression factor, both causally enforce each other). This would be a nice avenue for you to approach:

Robinaugh, D. J., Hoekstra, R. H., Toner, E. R., & Borsboom, D. (2019). The network approach to psychopathology: a review of the literature 2008–2018 and an agenda for future research. Psychological Medicine, 1-14.

Greene, T., Gelkopf, M., Epskamp, S., & Fried, E. (2018). Dynamic networks of PTSD symptoms during conflict. Psychological Medicine, 48(14), 2409-2417.

Snippe, E., Viechtbauer, W., Geschwind, N., Klippel, A., De Jonge, P., & Wichers, M. (2017). The impact of treatments for depression on the dynamic network structure of mental states: Two randomized controlled trials. Scientific Reports, 7, 4652

Fisher, A. J., Reeves, J. W., Lawyer, G., Medaglia, J. D., & Rubel, J. A. (2017). Exploring the idiographic dynamics of mood and anxiety via network analysis. Journal of Abnormal Psychology, 126(8), 1044.

Bringmann, L. F., Vissers, N., Wichers, M., Geschwind, N., Kuppens, P., Peeters, F., . . . Tuerlinckx, F. (2013). A network approach to psychopathology: new insights into clinical longitudinal data. Plos One, 8(4), e60188. doi:10.1371/journal.pone.0060188

Borsboom, D., & Cramer, A. O. J. (2013). Network analysis: An integrative approach to the structure of psychopathology. Annual Review of Clinical Psychology, 9(1), 91-121. doi:10.1146/annurev-clinpsy-050212-185608

Epskamp, S., Borsboom, D., & Fried, E. I. (2018). Estimating psychological networks and their accuracy: A tutorial paper. Behavior Research Methods, 50(1), 195-212. doi:10.3758/s13428-017-0862-1

HTH

Holger