Psychiatric Morbidity in Patients With Psoriasis

Comment

Studies investigating psychiatric morbidity in psoriasis have varying methodologies, mostly assessing psychiatric symptoms rather than screening for psychiatric disorders.³ In chronic diseases such as psoriasis, there often is an overlap between disease symptoms and common psychiatric disorders (eg, depression).¹¹ Therefore, assessment of symptoms can be misleading. The current study was designed to detect psychiatric disorders in psoriasis patients using both patient self-assessment and clinician-administered instruments. We also investigated the contribution of sociodemographic and clinical variables (eg, psoriasis severity, impairment in QOL) on psychiatric morbidity.

An increased risk for depression, anxiety, and suicidality associated with greater psoriasis severity has been reported.¹² The results of the current study indicate that even in a patient population with predominantly mild to moderate psoriasis, psychiatric morbidity, particularly DDs, is common. This finding was seen both on patient self-assessment and clinician-administered evaluations. Earlier studies from this institution and region have reported a lower prevalence of psychiatric disorders in patients with psoriasis (24.7%–36.7%).^13-16 However, prior studies were based on assessment of specific symptoms and clinical diagnoses derived from history and mental status examination rather than the administration of more rigorous research diagnostic assessment tools. A systematic review and meta-analysis also revealed a lower prevalence of clinical depression using International Classification of Diseases, Tenth Revision, and Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition) codes.³ A possible reason for this apparent discrepancy is the fact that psychiatric morbidity in a majority of participants in the current study was constituted by the diagnosis of dysthymia. If the diagnosis of dysthymia is removed from the current analysis, the prevalence of clinical major depressive syndromes is similar to other data. We found that chronic low-grade depression (dysthymia) was the most common diagnosis from the MINI. Lower prevalence was noted in a prior study, but methodology using clinical interviewing may have resulted in an underestimated prevalence.¹³ It also is possible that chronic low-grade depression in psoriasis patients may be missed or underestimated in comparison to more readily diagnosed and severe depressive syndromes in other studies. However, there is enough evidence to suggest that dysthymia is clinically relevant in the causation of morbidity and disability (eg, physical, psychological, or cognitive impairment) in patients with chronic physical disorders.¹⁷ This distinction between clinical major depressive syndrome and dysthymia is important because different treatment methods may be required; the former may warrant treatment with antidepressants in addition to psychosocial treatment modalities (eg, learning to cope with stress, problem-solving techniques), while the latter may benefit predominantly from psychosocial treatment modalities alone.^18,19 In the current study, most of the participants who were diagnosed with dysthymia refused treatment with any psychotropic medications but perceived benefit from discussing their problems with a professional. Our results indicated that chronic low-grade depression is more common than more severe major depressive states, and mental health professionals who are well versed in psychosocial treatment modalities should play an integral role in treatment planning for patients with psoriasis.

In the current study, there was only a modest correlation between the results of the patient self-assessment and clinician-administered evaluations, which indicated that psychiatric disorders may not be obvious to clinicians unless specifically investigated, even for some severely depressed and suicidal patients. Given the high prevalence of clinically relevant psychiatric morbidity among psoriasis patients, dermatology professionals should be more sensitive to the possible presence of psychiatric disorders in this patient population and should consider the use of formal screening or other diagnostic tools for detection of depression and anxiety in psoriasis patients.

The main determinant of psychiatric morbidity in our study population was impairment in QOL. Interestingly enough, psoriasis severity was not associated with psychiatric morbidity in our study. Depressive states in patients with chronic physical illnesses are well known and could be due to the chronic stress of illness or impaired QOL, or depression may be a direct effect of the illness and/or treatment on the central nervous system. Psoriasis is not known to have any direct effect on the central nervous system. Our findings suggest that QOL impairment plays an important role in psychiatric morbidity in patients with psoriasis. Even though the DLQI is designed to measure QOL over the preceding week, our findings suggest that impairment in QOL in psoriasis is a manifestation of a more long-term effect of interplay between many factors; the impairment in activities of daily living, disease-related physical discomfort and impaired self-esteem and self-perception, impairments in interpersonal relationships, and the stress of chronicity of illness seem to play an important role. Additionally, variables such as emotional dysfunction, magnitude and site of the area of involvement, nature and magnitude of comorbidities, and complications of illness and coping also may be relevant.²⁰ Although these factors are common in other chronic disorders, psoriasis in particular may predisposepatients to depression due to its unpredictable and relapsing nature, lack of any curative therapy, and the stigmatizing prominent lesions that often are impossible to camouflage. In chronic diseases such as psoriasis, the amelioration of impairment of different aspects of QOL may be more important than mere symptom control.

Our study was limited in that the study population was predominantly male. Fewer females may have consented to participate in the study due to time constraints associated with domestic responsibilities, reluctance to discuss psychological distress, or inability to meet the inclusion criteria (eg, level of education required to read questionnaires). However, there was no significant difference between males and females for sociodemographic variables or diagnoses other than alcohol-related disorders. Our study also had a cross-sectional design and there was no control group, without which it is difficult to assess the true prevalence and determinants of these psychiatric morbidities. Moreover, the sample size was small and did not include enough participants with moderate to severe psoriasis (ie, PASI score ≥10) to be able to detect a correlation between psychiatric morbidities and psoriasis severity. Our findings underline the need for effective screening and integrated management of psychiatric disorders in patients with psoriasis.