There is a lot of literature on that issue. I list here some references which may help you to track the issue. Just look at what has been cited in them and how they are later cited by other more new studies.

Carlsson, A. M. (1986). Personality characteristics of patients with chronic pain in comparison with normal controls and depressed patients. Pain, 25(3), 373-382.

Ekselius, L., Eriksson, M., von Knorring, L., & Linder, J. (1997). Comorbidity of personality disorders and major depression in patients with somatoform pain disorders or medical illnesses with long-standing work disability. Scand J Rehabil Med, 29(2), 91-96.

Kronholm, E., Partonen, T., Salminen, J., Mattila, A., & Joukamaa, M. (2008). Alexithymia, depression, and sleep disturbance symptoms. Psychotherapy And Psychosomatics, 77, 63-65.

Lumley, M. A., Tomakowsky, J., & Torosian, T. (1997). The relationship of alexithymia to subjective and biomedical measures of disease. Psychosomatics, 38(5), 497-502.

Main, C. J., Richards, H. L., & Fortune, D. G. (2000). Why put new wine in old bottles: the need for a biopsychosocial approach to the assessment, treatment, and understanding of unexplained and explained symptoms in medicine. J Psychosom Res, 48(6), 511-514.

McCrae, R. R., Costa, P. T., Jr., Ostendorf, F., Angleitner, A., Hrebickova, M., Avia, M. D., et al. (2000). Nature over nurture: temperament, personality, and life span development. J Pers Soc Psychol, 78(1), 173-186.

von Knorring, L., Almay, B. G., & Johansson, F. (1987). Personality traits in patients with idiopathic pain disorder. Acta Psychiatr Sca

nd, 76(5), 490-498.

von Knorring, L., Perris, C., Eisemann, M., Eriksson, U., & Perris, H. (1983). Pain as a symptom in depressive disorders. II. Relationship to personality traits as assessed by means of KSP. Pain, 17(4), 377-384.

Thanks a lot! I will look them up!

Personality traits and personality disorders are quite different concepts, the first pertaining to normal, the second pertaining to abnormal psychology and psychiatry.

It's true that many personality traits are labelled from the psychopathological conditions, but this is a fashion deriving from psychoanalysis.

Albeit there is a heap of research on personality traits (it's easy to take a personality test from the shelves and throw it into the battery), there is not much on personality disorders, which, however, are the most unreliable among the psychiatric diagnoses. Suffice here to say that only 10% of patients maintain the same diagnose of PD after 10 years, and only 50% of patients receive the same diagnose by different clinicians (with the same nosographic system!).

What seems much more promising to me is the approach in terms of trans-diagnostic mental dysfunctions. The study of such dysfunctions has gone into much detail so far, to the point that the psychiatric diagnoses seem outdated.

That is an important specification. Thank you Lucio. Francesca wrote about “specific personality disorders or "styles”. Personality “style” may denote to personality trait more than to personality disorder. Therefore I tried to include some references covering both approaches. However, I think that it is important for Francesca to clarify which approach is the one she is interested in.

Thank you for your very interesting answers. I do not totally agree, however, about the existence of a clear-cut distinction between normal and abnormal personality traits. In a dimensional (vs. nosographical) perspective, I tend to believe that what defines a "trait"as normal or pathological are characteristics such as its intensity, rigidity vs. flexibility in relation to context, and frequency of expression rather than its absolute "presence or absence". To this regard, though my theoretical approach and training background are quite distant from psychoanalysis, it seems interesting to me that an illuminating book on this issue comes from that field, i.e., "Neurotic styles" by Shapiro. Unfortunately, however, it is true that most research on personality is conducted with the classical "nosographical" approach, which creates a lot of confusion in my opinion. I would dare to speculate, in fact, that the problem of the stability of diagnosis suggested by Lucio depends on the accuracy of the former diagnosis, which is usually made according to standard manual criteria and not to underlying emotional-cognitive-behavioral styles (by the way, I believe a major problem of DSM classifications is that, among criteria for a certain disorder, there are some pertaining to manifest behaviour mixed with others pertaining to cognitive and relational factors, which creates a confusion in logical levels). It is evident that, once the diagnosis of presence or absence of BDP is made based on the presence of at least 5 criteria, if the patient stops showing even one of these criteria while maintaining the usual cognitive-emotional style he will still be borderline but not diagnosed as it.

Taking for granted the utility of nosographical approaches for practical communication purposes among clinicians, I would find more fruitful for the research context a dimensional approach, which could be labelled as "transdiagnostic", but which focuses on different variables from those currently used in the clinical and research contexts under the name of transdiagnostic (see papers by Harvey et al, Linton et al, etc). In my experience, in fact, the variables that are currently under focus as transdiagnostic are cognitive-behavioral mechanisms such as catastrophizing, rumination, avoidance behaviors. While I believe that the study of these processes may be very useful in understanding psychological functioning "downstream" (i.e. in the chronicization and maintenance of axis I disorders such as insomnia, depression, etc), and possibly in identifying factors to target in treatment, they do not give insight in the development of the disorder. In this sense, other “transdiagnostic” factors, pertaining to a different and more “upstream” logical level, could be more interesting, for instance deficits in emotional abilities (e.g., recognition, identification, labelling, regulation, expression of emotions) and in metacognitive abilities (e.g., integration, differentiation, decentering, mastery). I imagine an etiological model in which the individual has a certain cluster of deficits in emotional and metacognitive abilities; according to the specific cluster of deficits he will show a certain cognitive-emotional-behavioural pattern which can be assimilated to what we call personality disorders (see for instance literature from Semerari et al. on specific metacognitive deficits associated to specific personality disorders) even though he does not necessarily respond to all DSM criteria. In moments of particular stress, this general psychological discomfort can give rise to Axis I disorders (which I would more appropriately label “symptoms”), that may be maintained and chronicized through the downstream transdiagnostic processes I mentioned (avoidant behaviors, catastrophizing, etc).

The issue that intrigues me, thus, is the pathway leading from a certain “personality pattern” (which is normal or pathological just according to its intensity and flexibility/rigidity) to a certain axis I symptom. In other words, is it more probable that a paranoid personality (defined for instance by prevalent deficits in differentiation and decentering and difficulties in regulating fear/anxiety) develops a sleep problem, or a depression, or a phobia, etc? Or is the specific axis I symptom determined by different, non psychological variables such as accidental factors (for instance being a shift-worker can trigger a sleep problem rather than a phobia) or biological vulnerabilities? Or all three of these factors? Research on this topic could help make predictions of which kind of symptoms to expect in certain patients, and thus could have interesting implications on prevention. Also, at the level of treatment, I would expect that targeting the core deficits (those in emotional and metacognitive abilities) would yield stronger and more stable effects compared to interventions focused on those transdiagnostic mechanisms that I believe act “more downstream” (catastrophizing, rumination, etc).

I didn’t have time yet to review the literature kindly suggested by Erkki, a part from a couple of articles I already knew. For now, I just wanted to clarify my question and the kind of reasoning it comes from. I would really appreciate your feedback on this theoretical model, especially disconfirmations (a hypothesis is never a good one if it cannot be falsified!).

Sorry that I haven't had time to respond earlier. If I got you right, I must addmit that your specific reasearch problem is out of my proper expertice. But as far as I follow your thinking it seems to me worth for pursuing. As a sleep researcher I know that studies on relationships between sleep (problems) and different personality and/or temperament dimensions haven't got so much interest today as they used to have some decades ago. However, that does not mean that they don't deserve that. Simply sleep community has had so many new problems and promising new methodological approaches which have directed the interest of the researchers towards other problems. But I would say that perhaps the wind is changing. At least we do now realize that sleep is directly connected with the mood regulation, not simply by being a 'risk factor' for e.g. depression but, litteraly, being directly involved with the normal mood regulation in itself. There are fascinating studies on this issue by Mathew Walker and his co-workes. If you are not yet familiar with them, I think that you may find them usefull for developing your ideas. I wish you success!

Thank you very much, I really appreciate interesting feedbacks from more expert researchers than me! I am familiar with Walker's studies on sleep and emotions and I will certainly give them a further look. I will keep you posted if I get to write/find anything more about the issue!

I have no theoretical clues about your question as its not my field, but it was interesting for a while to realize -online- how most of my friends ( tens of tens) sleeping habits have changed during the Syrian revolution. The amount of tension, the sequence of events, the escalation of events, even adrenaline rush made them/us stay out late at night ! I dont know if this is of any help to your research/area of interest but i thought sharing this from personal and observational perspective might help. The problem, is that facebook (by example) doesnt give freely or even paid such anonymous information that would give confirmatory evidences.