**1. Introduction**

208 Psoriasis

Tuckey RC. Progesterone synthesis by the human placenta, Placenta 2005; 26: 273–281.

Verhoeven EW, Kraaimaat FW, de Jong EM, Schalkwijk J, van de Kerkhof PC, Evers AW.

Wakamatsu K, Graham A, Cook D, Thody AJ. Characterization of ACTH peptides in human

Weatherhead SC, Farr PM, Jamieson D, Hallinan JS, Lloyd JJ, Wipat A, Reynolds NJ.

Wintzen M, Yaar M, Burbach JP, Gilchrest BA. Proopiomelanocortin gene product

Wong M, Licinio J, Pasternak K I, Gold P W. Localization of corticotropin- releasing

Xiang Z, Nilsson G. IgE receptor-mediated release of nerve growth factor by mast cells. Clin

Zangeneh FZ, Fazeli A. The significance of stress hormones in psoriasis. Acta Medica Iranica

Zangeneh FZ، Shooshtary FS. Chronic Stress and Limbic-Hypothalamopituitary-Adrenal

Zbytek B, Mysliwski A, Slominski A, Wortsman J, Wei ET, Mysliwska J. Corticotropin-

Zhou C, Yu X, Cai D, Liu C, Li C. Role of corticotropin-releasing hormone and receptor in the pathogenesis of psoriasis. Medical Hypotheses 2009; 73: 513-515.

regulation in keratinocytes. J. Invest. Dermatol. 1996; 106: 673–678.

actions and mechanisms of action. Physiol Rev. 1999; 79:1–71.

study. J Invest Dermatol. 2009; 129: 2075–7.

immunity. Curr Opin Immunol. 2000; 12: 624-31.

histochemistry. Endocrinology 1994; 135: 2275– 8.

Exp Allergy. 2000; 30: 1379-86.

Reproductive Health 2009 ;3: 101-108.

2008; 46: 485-488.

Sci. 2002;70: 1013-21.

288–297.

Vassar R, Fuchs E. Transgenic mice provide new insights into the role of TGF-alpha during epidermal development and differentiation. Genes Dev. 1991; 5: 714–727. Turnbull AV, Rivier CL. Regulation of the hypothalamic-pituitary-adrenal axis by cytokines:

Individual differences in the effect of daily stressors on psoriasis: a prospective

skin and their activation of the melanocortin-1 receptor. Pigment Cell Res. 1997; 10:

Keratinocyte Apoptosis in Epidermal Remodeling and Clearance of Psoriasis Induced by UV Radiation. Invest Dermatol. 2011 May 26. [Epub ahead of print] Wedemeyer J, Tsai M, Galli SJ. Roles of mast cells and basophils in innate and acquired

hormone (CRH) receptor mRNA in adult rat brain by in situ hybridization

Axis (LHPA) Response in Female Reproductive system. Journal of Family and

releasing hormone affects cytokine production in human HaCaT keratinocytes. Life

#### **1.1 Skin diseases and psychological factors**

It has been known since antiquity that a connection exists between the skin and the mind. In fact, the first documented case of psychodermatosis dates to 1700 BC, when the physician to the prince of Persia speculated that the prince's psoriasis was caused by anxiety over succeeding his father to the throne (Shafii & Shafii, 1979). However, it was not until 1891 that Brocq and Jacquet coined the term neurodermatitis and hypothesised that there was a pathological association between the skin and the autonomic nervous system, given that itching precipitates the appearance of lesions (Braun-Falco, Plewig, Wolff, & Winkelmann). A further 62 years passed before "Emotional Factors in Skin Disease" (Wittkower & Russell, 1953) was published. Since then, physicians, and dermatologists in particular, have been steadily becoming aware of the impact of an individual's emotional state on skin disease and how this organ can reflect, like a mirror, their psychological state. It should come as no surprise that these two structures have a common origin in the ectoderm.

Psychological factors have traditionally been associated with the onset, development, and persistence of skin disease (Alexander, 1951) and there is evidence to suggest an association between stress and the exacerbation of skin lesions (Kimyai-Asadi & Usman, 2001; Robles, 2007; Vileikyte, 2007). Recent longitudinal studies of a general hospital population show the involvement of psychological factors, such as stress, depression, and anxiety, in individuals who present skin disease (Magin, Sibbritt, & Bailey, 2009). In addition to depression or anxiety (da Silva, Müller, & Bonamigo, 2006; Fried, Gupta, & Gupta, 2005; Lotti, Buggiani et al., 2008; Morell-Dubois et al., 2008; Radmanesh & Shafiei, 2001; Richards & Fortune, 2006), higher rates of dissociative disorders (Konuk, 2007; Gupta, 2006), sexual dysfunction (Mercan, 2008) or problems of excessive alcohol consumption attributed to psychological distress (Kirby et al., 2008) have been found in this group than in the healthy population. Psoriasis has been associated with psychological distress, such as feelings of shame, shyness, low self-esteem, and stigmatization (Magin, Adams, Heading, Pond, & Smith, 2009).

Psychological stress occupies a special place among the factors that trigger psoriasis, of which patients are very aware. They openly identify it as underlying many of their

*TR*], 2000).

1990).

agents.

Personality in Patients with Psoriasis 211

personality categories presented in DSM-IV (American Psychiatric Association [*DSM-IV-*

The healthy personality, conceived of in this way, would reflect the specific adaptation modes that individuals find effective in their environment. In turn, personality disorders would be represented by the various maladaptive response styles that can be attributed to deficiencies, imbalances, or conflicts in an individual's capacity to relate to his or her environment (Millon, 2001). In the context of Millon's evolutionary theory, strategies that favour individual survival and reproductive are equivalent to the personality (Million,

Million compared the personality to the immune system. According to this perspective, the personality can be studied as an interface between the outer and inner world, as described by Freud (Quiroga, 2003), and between the social and biological levels. Just as in the biological perspective the skin or immune system protects the individual from external attacks and maintains the internal environment in homeostasis, similarly, Million suggested that within the framework of the DSM-IV, axis I (clinical disorders due to anxiety or depression, etc), would be equivalent to cough or fever, axis II (personality disorders) would represent a coping style equivalent to the immune system, and axis IV (psychological and social stressors, such as marital or economic conflict) would be analogous to infectious

Personality would be a complex behavioural system that evolved due to the need to deal with a threatening environment undergoing constant change (Million, 1990; Millon, 1999). Million suggested that the different ways of dealing with the environment may be more or less adaptative. It is of interest to apply these ideas to dermatology. Adaptive personality styles could modulate external events and ensure, with increased likelihood, the maintenance of physiological states that may allow the skin to function in a healthy way. However, individuals who experience difficulty in adaptation can be more vulnerable to stressful events and their impact on health. That is, biological differences may not only be due to genetic factors but to an entire group of environmental factors (Davidson, 2001).

Studies have shown how certain personality variables can modulate response to stress. Associations have been found between the tendency to experience positive or negative emotions and extraversion or neuroticism (personality variables), respectively (Ng, 2009). These tendencies may modulate the effect that emotional responses to stressful events have

In general, psychological stress has been frequently described as a variable that triggers skin disease, and has been commonly associated with high levels of sympathetic activation and difficulties in regulating emotions (Arck & Paus, 2006; Berg, Svensson, Brandberg, & Nordlind, 2008; Gupta, 2008; Gupta & Gupta, 2004; Mastrolonardo, Alicino, Zefferino, Pasquini, & Picardi, 2007; Arck, 2006; Picardi, Pasquini, Cattaruzza, Gaetano, Melchi, et al.,

It has also been proposed that patients with skin disease usually present psychological traits that would make them vulnerable to stress (Cordan Yazici et al., 2006; Kim et al., 2006; Papadopoulos, 2003). In fact, psoriasis-associated psychological vulnerability has been described (Valverde, Mestanza, & Asenjo, 2005) and increased reactivity of the

on the physiology of the skin (Mardaga Solange, 2006).

2003; Wright, Cohen, & Cohen, 2005).

outbreaks of psoriasis. In 1998, the National Psoriasis Foundation (NPF) published the preliminary results of a survey that had been answered by 18,000 psoriasis patients who were members of the NPF. When they were asked to identify the factors that aggravate psoriasis, 52% answered that emotional stress was the most frequent trigger. Some 41% attributed outbreaks to seasonal changes, 9% to chemical substances, 8% to medications, 8% to certain food or diets, 7% to alcohol, and 29% did not know (Annual Report, 1998). Thus, emotional stress was considered the most important factor by more of half of the sample. Subsequently, their findings were published in a scientific journal (Krueger et al., 2001).

The high percentage of dermatological patients who need psychiatric care is also striking. This ranges from 25.2% reported in a sample of 2579 patients attending a dermatology unit (Picardi, Abeni, Melchi, Puddu, & Pasquini, 2000) to 95% of the dermatological patients who fulfilled the criteria for a psychiatric disorder and were referred to a psychosomatic medicine specialist (Woodruff, Higgins, Du Vivier, & Wessely, 1997). A study that reviewed the prevalence of psychiatric symptoms in psoriasis patients found a higher rate of psychiatric disorders than in the healthy population (Russo, Ilchef, & Cooper, 2004). Similarly, another study found that the prevalence of psychiatric disease among psoriasis patients was less than in psychiatric patients but higher than in healthy controls (Chaudhury, Das, John, & Ramadasan, 1998). Psoriasis patients experience a greater number of stressful events (Jankovic et al., 2009; Malhotra & Mehta, 2008; Picardi et al., 2003). A prospective study which measured daily stressors in psoriasis patients found a direct association between disease severity and increased itching on days perceived as more stressful, but not on days of medium or low stress (Verhoeven et al., 2009).

It is generally accepted that psoriasis patients experience reduced quality of life (Hong, Koo, & Koo, 2008). Compared to healthy subjects, psoriasis patients experience greater physical discomfort, mood swings, poor body image and self image, and restricted daily and social activities due to their lesions (De Korte, Sprangers, Mombers, & Bos, 2004). Other authors have found a stronger association between quality of life and psychological variables and fear of rejection than with the physical characteristics of the disease, such as the extent of the lesions and their visibility (Kimball, Jacobson, Weiss, Vreeland, & Wu, 2005). In an intermediate position, some authors suggest that the relationship between psoriasis and psychiatric symptoms could be reciprocal (Devrimci Ozguven, Kundakci, Kumbasar, & Boyvat, 2000).

#### **1.2 Personality, stress, and skin**

Given the role of the skin as the interface between the external and internal environment, the personality would be the psychological construct fulfilling the same role between the internal and external environment. That is, the personality would be the psychological analogue of the skin.

The term personality represents the different behavioural styles that individuals present in their habitual habitats or environments (Davis, 1999). In other words, the personality would be the means of responding to the environment. According to Darwinian theory, individuals behave in the way that is most conducive to reproductive success. Millon selected several characteristics present in all living beings and, based on these, generated a dimensional system to classify the way individuals adapt to their environment, thus matching the

outbreaks of psoriasis. In 1998, the National Psoriasis Foundation (NPF) published the preliminary results of a survey that had been answered by 18,000 psoriasis patients who were members of the NPF. When they were asked to identify the factors that aggravate psoriasis, 52% answered that emotional stress was the most frequent trigger. Some 41% attributed outbreaks to seasonal changes, 9% to chemical substances, 8% to medications, 8% to certain food or diets, 7% to alcohol, and 29% did not know (Annual Report, 1998). Thus, emotional stress was considered the most important factor by more of half of the sample. Subsequently, their findings were published in a scientific journal (Krueger et al., 2001).

The high percentage of dermatological patients who need psychiatric care is also striking. This ranges from 25.2% reported in a sample of 2579 patients attending a dermatology unit (Picardi, Abeni, Melchi, Puddu, & Pasquini, 2000) to 95% of the dermatological patients who fulfilled the criteria for a psychiatric disorder and were referred to a psychosomatic medicine specialist (Woodruff, Higgins, Du Vivier, & Wessely, 1997). A study that reviewed the prevalence of psychiatric symptoms in psoriasis patients found a higher rate of psychiatric disorders than in the healthy population (Russo, Ilchef, & Cooper, 2004). Similarly, another study found that the prevalence of psychiatric disease among psoriasis patients was less than in psychiatric patients but higher than in healthy controls (Chaudhury, Das, John, & Ramadasan, 1998). Psoriasis patients experience a greater number of stressful events (Jankovic et al., 2009; Malhotra & Mehta, 2008; Picardi et al., 2003). A prospective study which measured daily stressors in psoriasis patients found a direct association between disease severity and increased itching on days perceived as more

It is generally accepted that psoriasis patients experience reduced quality of life (Hong, Koo, & Koo, 2008). Compared to healthy subjects, psoriasis patients experience greater physical discomfort, mood swings, poor body image and self image, and restricted daily and social activities due to their lesions (De Korte, Sprangers, Mombers, & Bos, 2004). Other authors have found a stronger association between quality of life and psychological variables and fear of rejection than with the physical characteristics of the disease, such as the extent of the lesions and their visibility (Kimball, Jacobson, Weiss, Vreeland, & Wu, 2005). In an intermediate position, some authors suggest that the relationship between psoriasis and psychiatric symptoms could be reciprocal (Devrimci Ozguven, Kundakci, Kumbasar, &

Given the role of the skin as the interface between the external and internal environment, the personality would be the psychological construct fulfilling the same role between the internal and external environment. That is, the personality would be the psychological

The term personality represents the different behavioural styles that individuals present in their habitual habitats or environments (Davis, 1999). In other words, the personality would be the means of responding to the environment. According to Darwinian theory, individuals behave in the way that is most conducive to reproductive success. Millon selected several characteristics present in all living beings and, based on these, generated a dimensional system to classify the way individuals adapt to their environment, thus matching the

stressful, but not on days of medium or low stress (Verhoeven et al., 2009).

Boyvat, 2000).

analogue of the skin.

**1.2 Personality, stress, and skin** 

personality categories presented in DSM-IV (American Psychiatric Association [*DSM-IV-TR*], 2000).

The healthy personality, conceived of in this way, would reflect the specific adaptation modes that individuals find effective in their environment. In turn, personality disorders would be represented by the various maladaptive response styles that can be attributed to deficiencies, imbalances, or conflicts in an individual's capacity to relate to his or her environment (Millon, 2001). In the context of Millon's evolutionary theory, strategies that favour individual survival and reproductive are equivalent to the personality (Million, 1990).

Million compared the personality to the immune system. According to this perspective, the personality can be studied as an interface between the outer and inner world, as described by Freud (Quiroga, 2003), and between the social and biological levels. Just as in the biological perspective the skin or immune system protects the individual from external attacks and maintains the internal environment in homeostasis, similarly, Million suggested that within the framework of the DSM-IV, axis I (clinical disorders due to anxiety or depression, etc), would be equivalent to cough or fever, axis II (personality disorders) would represent a coping style equivalent to the immune system, and axis IV (psychological and social stressors, such as marital or economic conflict) would be analogous to infectious agents.

Personality would be a complex behavioural system that evolved due to the need to deal with a threatening environment undergoing constant change (Million, 1990; Millon, 1999). Million suggested that the different ways of dealing with the environment may be more or less adaptative. It is of interest to apply these ideas to dermatology. Adaptive personality styles could modulate external events and ensure, with increased likelihood, the maintenance of physiological states that may allow the skin to function in a healthy way. However, individuals who experience difficulty in adaptation can be more vulnerable to stressful events and their impact on health. That is, biological differences may not only be due to genetic factors but to an entire group of environmental factors (Davidson, 2001).

Studies have shown how certain personality variables can modulate response to stress. Associations have been found between the tendency to experience positive or negative emotions and extraversion or neuroticism (personality variables), respectively (Ng, 2009). These tendencies may modulate the effect that emotional responses to stressful events have on the physiology of the skin (Mardaga Solange, 2006).

In general, psychological stress has been frequently described as a variable that triggers skin disease, and has been commonly associated with high levels of sympathetic activation and difficulties in regulating emotions (Arck & Paus, 2006; Berg, Svensson, Brandberg, & Nordlind, 2008; Gupta, 2008; Gupta & Gupta, 2004; Mastrolonardo, Alicino, Zefferino, Pasquini, & Picardi, 2007; Arck, 2006; Picardi, Pasquini, Cattaruzza, Gaetano, Melchi, et al., 2003; Wright, Cohen, & Cohen, 2005).

It has also been proposed that patients with skin disease usually present psychological traits that would make them vulnerable to stress (Cordan Yazici et al., 2006; Kim et al., 2006; Papadopoulos, 2003). In fact, psoriasis-associated psychological vulnerability has been described (Valverde, Mestanza, & Asenjo, 2005) and increased reactivity of the

Personality in Patients with Psoriasis 213

the case among patients with other skin diseases such as acne (Krejci-Manwaring, Kerchner, Feldman, Rapp, & Rapp, 2006). All the evidence suggests that the patients themselves are one of the main sources of stigmatization and despair and that these feelings are not caused

It has been suggested that psoriasis patients have a particular way of reacting to feelings of stigmatization and that their feelings are divided and denied, to the point that the fact of being rejected due to psoriasis significantly predicted alcohol consumption, without the patient being consciously aware of feeling stigmatized because of the disease. Thus, the patients act out their feelings without being aware of their relationship to behaviour

To sum up, psoriasis, as well as other skin diseases, has frequently been associated with emotional disturbances, vulnerability to stress, and difficulty in expressing emotions. However, up to the present, no personality differences between psoriasis patients and the healthy population have been found. Matussek, Agerer & Seibt reported differences in personality traits between healthy individuals and those with psoriasis (Matussek, Agerer, & Seibt, 1985), but this was not corroborated in later studies conducted by Doodley and Finlay (Dooley & Finlay, 1990), Ginsburg et al. (Ginsburg & Link, 1993) and Gupta et al. (Gupta et al., 1989). Although some studies have identified personality traits associated with the development or exacerbation of skin disease, including psoriasis (Magin, Pond, Smith, Watson, & Goode, 2008), no differences have been found between the healthy population and the psoriatic population or the findings have not been conclusive (Pérez et al., 2000; Willemsen, Roseeuw, & Vanderlinden, 2008). Therefore, more research is required on the way personality traits modulate the course of skin disease (Verhoeven et al., 2008). For example, the hypothesis that individuals with psoriasis share common personality traits that are related to the exacerbation of

Despite some evidence suggesting that psoriasis patients have poor quality of life, experience emotional disturbances, are vulnerable to stressful events, suffer feelings of stigmatization that are independent of lesion severity, and possibly share nonfunctional personality traits, it cannot be asserted beyond doubt that these patients have personality

To test this hypothesis a study including 36 psoriasis patients attending the Reina Sofía University Hospital (Murcia, Spain) was conducted. The inclusion criterion was the presence of psoriasis as diagnosed by a dermatologist who agreed to participate in the

The exclusion criteria were as follows: severe psychological disorders such as psychosis, factitious or simulation disorders, neurological disorders, etc. Given that the Million Index of Personality Styles (MIPS) is designed to evaluate the personality of individuals more than

Regarding comorbidity, high levels of depression and anxiety are often observed in populations with skin disease (Konuk, 2007); however, the study participants did not have a

by the disease.

(Ginsburg & Link, 1993).

symptoms has only been partially upheld.

traits that differ from the healthy population.

18 years old, younger patients were excluded.

**2. Is there a different personality profile in psoriasis?** 

study. Patients were recruited between October 2005 and June 2009.

hypothalamic-pituitary-adrenal axis has been found in patients with this disease (Richards, Ray, et al., 2005); thus, the link between stressful events and psychological vulnerability may play an important role in the development of skin disease (Laguna, Pena Payero, & Marquez, 2006).

Higher levels of alexithymia have been found among psoriasis patients and other skin diseases than in control groups (Gupta, 2006). One study assessed alexithymia before and after patients received PUVA therapy which led to lesion regression. The level of alexithymia did not vary and thus this disorder could not be a response to the severity of the lesions or the degree of discomfort occasioned by them (Richards, Fortune, Griffiths, & Main, 2005). The authors suggested that alexithymia could be understood as a stable internal psychological trait more than as a strategy to cope with the lesions. Other researchers have not found higher levels of alexithymia in patients with skin disease (Picardi, Pasquini, Cattaruzza, Gaetano, Baliva, et al., 2003).

Taking this into account, it is not surprising that some authors have proposed psoriasis as a psychosomatic disease due to the close link between stress and the exacerbation of psoriasis lesions (Ginsburg, 1995; Kilic, Gulec, Gul, & Gulec, 2008). One of the most valuable, rigorous, and exhaustive studies of psoriasis concluded that the disease is caused by genetic and environmental factors, influenced by psychological stress, and where the patients' attitudes, knowledge of, and behavior towards their disease have a profound effect on its course and severity (Ginsburg, 1995). The author suggested that psoriasis, by attacking the skin, attacks the individual's sense of identity. Thus, the relationship between skin and identity is implicit. In a survey of NPF members conducted by Jobling, 84% of respondents stated that the worst aspect of having psoriasis was the difficulty involved in establishing relationships. What is striking is that few respondents had experienced avoidance or exclusion, such that the problem was more related to their constant anticipation of this occurring rather than it being a real event (Jobling, 1976).

Doodley and Finlay attempted to define social adjustment in psoriasis patients by examining the relationship between subjective experience and various social situations, such as wearing a swimming suit (Dooley & Finlay, 1990). They found no correlation between chronicity, the natural course of the disease, visibility, and the various measures of social adjustment taken by the experimental group compared to the control group.

In an attempt to provide an in-depth account of the patients' subjective experience, Ginsburg and Link assessed 100 patients using the concept of stigma defined as a negative social or biological mark that sets a person off from others and changes how they interact with other people due to the anticipation of rejection, among other reasons. Although bleeding is not one of the main symptom of psoriasis, it is strongly correlated with stigma. This may be caused by scratching scales or their removal that leads to punctate bleeding spots known as Auspitz's sign. Regarding all the aspects of the disease, bleeding lesions was the strongest predictor of feelings of being stigmatized and despair. Thus, feelings of despair and stigmatization may lead to non-compliance with treatment, possibly aggravating the disease (Ginsburg & Link, 1989).

In relation to feelings of stigmatization, evidence suggests that psoriasis patients fear being rejected or negatively labelled, regardless of physical lesions (Richards, Fortune, Griffiths, & Main, 2001). This could be modulated by personality variables (Schmid-Ott et al., 2005), as is

hypothalamic-pituitary-adrenal axis has been found in patients with this disease (Richards, Ray, et al., 2005); thus, the link between stressful events and psychological vulnerability may play an important role in the development of skin disease (Laguna, Pena Payero, &

Higher levels of alexithymia have been found among psoriasis patients and other skin diseases than in control groups (Gupta, 2006). One study assessed alexithymia before and after patients received PUVA therapy which led to lesion regression. The level of alexithymia did not vary and thus this disorder could not be a response to the severity of the lesions or the degree of discomfort occasioned by them (Richards, Fortune, Griffiths, & Main, 2005). The authors suggested that alexithymia could be understood as a stable internal psychological trait more than as a strategy to cope with the lesions. Other researchers have not found higher levels of alexithymia in patients with skin disease

Taking this into account, it is not surprising that some authors have proposed psoriasis as a psychosomatic disease due to the close link between stress and the exacerbation of psoriasis lesions (Ginsburg, 1995; Kilic, Gulec, Gul, & Gulec, 2008). One of the most valuable, rigorous, and exhaustive studies of psoriasis concluded that the disease is caused by genetic and environmental factors, influenced by psychological stress, and where the patients' attitudes, knowledge of, and behavior towards their disease have a profound effect on its course and severity (Ginsburg, 1995). The author suggested that psoriasis, by attacking the skin, attacks the individual's sense of identity. Thus, the relationship between skin and identity is implicit. In a survey of NPF members conducted by Jobling, 84% of respondents stated that the worst aspect of having psoriasis was the difficulty involved in establishing relationships. What is striking is that few respondents had experienced avoidance or exclusion, such that the problem was more related to their constant anticipation of this

Doodley and Finlay attempted to define social adjustment in psoriasis patients by examining the relationship between subjective experience and various social situations, such as wearing a swimming suit (Dooley & Finlay, 1990). They found no correlation between chronicity, the natural course of the disease, visibility, and the various measures of social

In an attempt to provide an in-depth account of the patients' subjective experience, Ginsburg and Link assessed 100 patients using the concept of stigma defined as a negative social or biological mark that sets a person off from others and changes how they interact with other people due to the anticipation of rejection, among other reasons. Although bleeding is not one of the main symptom of psoriasis, it is strongly correlated with stigma. This may be caused by scratching scales or their removal that leads to punctate bleeding spots known as Auspitz's sign. Regarding all the aspects of the disease, bleeding lesions was the strongest predictor of feelings of being stigmatized and despair. Thus, feelings of despair and stigmatization may lead to non-compliance with treatment, possibly

In relation to feelings of stigmatization, evidence suggests that psoriasis patients fear being rejected or negatively labelled, regardless of physical lesions (Richards, Fortune, Griffiths, & Main, 2001). This could be modulated by personality variables (Schmid-Ott et al., 2005), as is

adjustment taken by the experimental group compared to the control group.

(Picardi, Pasquini, Cattaruzza, Gaetano, Baliva, et al., 2003).

occurring rather than it being a real event (Jobling, 1976).

aggravating the disease (Ginsburg & Link, 1989).

Marquez, 2006).

the case among patients with other skin diseases such as acne (Krejci-Manwaring, Kerchner, Feldman, Rapp, & Rapp, 2006). All the evidence suggests that the patients themselves are one of the main sources of stigmatization and despair and that these feelings are not caused by the disease.

It has been suggested that psoriasis patients have a particular way of reacting to feelings of stigmatization and that their feelings are divided and denied, to the point that the fact of being rejected due to psoriasis significantly predicted alcohol consumption, without the patient being consciously aware of feeling stigmatized because of the disease. Thus, the patients act out their feelings without being aware of their relationship to behaviour (Ginsburg & Link, 1993).

To sum up, psoriasis, as well as other skin diseases, has frequently been associated with emotional disturbances, vulnerability to stress, and difficulty in expressing emotions. However, up to the present, no personality differences between psoriasis patients and the healthy population have been found. Matussek, Agerer & Seibt reported differences in personality traits between healthy individuals and those with psoriasis (Matussek, Agerer, & Seibt, 1985), but this was not corroborated in later studies conducted by Doodley and Finlay (Dooley & Finlay, 1990), Ginsburg et al. (Ginsburg & Link, 1993) and Gupta et al. (Gupta et al., 1989). Although some studies have identified personality traits associated with the development or exacerbation of skin disease, including psoriasis (Magin, Pond, Smith, Watson, & Goode, 2008), no differences have been found between the healthy population and the psoriatic population or the findings have not been conclusive (Pérez et al., 2000; Willemsen, Roseeuw, & Vanderlinden, 2008). Therefore, more research is required on the way personality traits modulate the course of skin disease (Verhoeven et al., 2008). For example, the hypothesis that individuals with psoriasis share common personality traits that are related to the exacerbation of symptoms has only been partially upheld.

Despite some evidence suggesting that psoriasis patients have poor quality of life, experience emotional disturbances, are vulnerable to stressful events, suffer feelings of stigmatization that are independent of lesion severity, and possibly share nonfunctional personality traits, it cannot be asserted beyond doubt that these patients have personality traits that differ from the healthy population.
