Patient Health Questionnaire Somatic Symptom Severity Scale (PHQ-15)

In the mid-1990s the Patient Health Questionnaire (PHQ), was developed and validated as a shorter self-administered version of the Primary Care Evaluation of Mental Disorders (PRIME-MD). The PHQ was developed by Robert Spitzer, Janet Williams and Kurt Kroenke and colleagues at Columbia University. A large study found the PHQ had diagnostic validity comparable to the original clinician-administered PRIME-MD and was more efficient in clinical practice (Spitzer et al., 1999). The Patient Health Questionnaire Somatic Symptom Severity Scale (PHQ-15) is a brief, self-administered questionnaire that was derived from the full PHQ and is increasingly used to assess somatic symptom severity and screen for the potential presence of somatisation and somatoform disorders (based on DSM-IV criteria) in adults (Kroenke et al., 2002). The scale consists of 15 items that ask whether somatic symptoms, such as stomach pain or dizziness are present within the last 4 weeks and the severity (response categories of “not bothered at all”, “bothered a little” and “bothered a lot”). The PHQ-15 scores of 5, 10, and 15 represent cut off points for low, medium, and high somatic symptom severity, respectively (Spritzer et al., 1994).

Psychometric Properties

The PHQ-15 has been validated in different clinical and occupational populations. (De Vroege et al., 2012; Kroenke et al., 2010). With a cut off score of 6 or more the sensitivity of the PHQ-15 was 78% (true positive) and specificity was 71% (false negative). The negative predictive value of 97% indicates that only 3% of individuals who have a score of less than 6 will have a somatoform disorder (Van Ravesteijn et al., 2009). Convergent validity with the Beck Depression Inventory (BDI) and the General Health Questionnaire-12 (GHQ-12) were positive. Increasing scores on the PHQ-15 are strongly associated with increased functional impairment, disability, health care use and symptom-related difficulty (Changsu et al., 2009; Kroenke et al., 2002).  The PHQ-15 demonstrates acceptable internal consistency (Cronbach coefficient alpha of .80) (Kroenke et al., 2002; Van Ravesteijn et al., 2009; Kroenke et al., 1998). The PHQ-15 has moderate test-retest reliability (intraclass correlation coefficient of 0.83) with a 2 week interval (Van Ravesteijn et al., 2009).

The reliability and validity of the PHQ-15 is unaffected by pertinent individual difference factors such as age, gender and education (Kroenke et al., 2010; Kocalevent et al., 2013; Changsu et al., 2009; Shih-Cheng et al., 2016). The PHQ-15 has been translated into over 20 languages (Spritzer et al., 1994). The scale has been validated in Korean and Chinese populations, however does not perform well in Hispanic populations which could be due to multiple factors within the cultural context that may affect how individuals identify and classify bodily sensations, perceive illness and seek medical attention (APA, 2013; Interian et al., 2006; Changsu et al., 2009; Shih-Cheng et al., 2016). East Asian populations often complain of somatic symptoms rather than reveal any depressive feelings, which is important for clinical practice as somatoform disorders have considerable comorbidity with anxiety and depressive disorders which the PHQ-15 does not screen for (Changsu et al., 2009).

Clinical utility

Overall, the PHQ-15 is a valid and reliable screening tool for presence of somatic symptoms and severity. The DSM-IV main criteria for somatoform disorder was medically unexplained symptoms, whereas, the DSM-5 emphasises distress (APA, 2013). Therefore, the PHQ-15 can be aligned with the DSM-5 criteria as the scale is a screening tool of severity and distress (Shih-Chen et al., 2016). More research is needed to support the PHQ-15 as a measure of responsiveness to changes throughout treatment of individuals with somatoform disorders (Kroenke et al., 2010). It is important to note the PHQ-15 is a self-report scale therefore susceptible to reporting biases. Elevated neuroticism or negative affectivity may lead to inflated symptom reporting (Watson et al., 1989). The main strengths of the scale are it is easy to use (for clinician and client), free and has been validated in different clinical and occupational populations. It has shown good sensitivity and specificity for screening for somatoform disorders, however it is not a diagnostic tool rather an indication of an individual at risk (Kroenke et al., 2010). Further, the scale addresses current rather than previous symptoms to gain more valid and reliable data (Kroenke et al., 2010).

Link to free version of PHQ-15


American Psychiatric Association (APA). (2013). Diagnostic and statistical manual of mental disorders: DSM-5. Washington, D.C: American Psychiatric Association.

Spitzer, R., Williams, J., & Kroenke, K. (1994). Instructions for Patient Health Questionnaire (PHQ) and GAD-7 Measures (pp. 1-9). Retrieved from

Spitzer, R., Kroenke, K., & Williams, J. (1999). Validation and Utility of a Self-report Version of PRIME-MD. The Patient Health Questionnaire Primary Care Study Group. JAMA, 282(18), 1737–1744. doi:10.1001/jama.282.18.1737

Kroenke, K., Spitzer, R., & Williams, J. (2002). The PHQ-15: Validity of a New Measure for Evaluating the Severity of Somatic Symptoms. Psychosomatic Medicine64(2), 258-266.

Kroenke, K., Spitzer, R., Williams, J., & Löwe, B. (2010). The Patient Health Questionnaire Somatic, Anxiety, and Depressive Symptom Scales: a systematic review. General Hospital Psychiatry, 32(4), 345-359.

Han, C., Pae, C., Patkar, A., Masand, P., Woong Kim, K., Joe, S., & Jung, I. (2009). Psychometric Properties of the Patient Health Questionnaire–15 (PHQ–15) for Measuring the Somatic Symptoms of Psychiatric Outpatients. Psychosomatics, 50(6), 580-585.

Liao, S., Huang, W., Ma, H., Lee, M., Chen, T., Chen, I., & Gau, S. (2016). The relation between the patient health questionnaire-15 and DSM somatic diagnoses. BMC Psychiatry, 16(1).

Van Ravesteijn, H., Wittkampf, K., Lucassen, P., van de Lisdonk, E., van den Hoogen, H., & van Weert, H. et al. (2009). Detecting Somatoform Disorders in Primary Care With the PHQ-15. The Annals Of Family Medicine, 7(3), 232-238.

Interian, A., Allen, L., Gara, M., Escobar, J., & Díaz-Martínez, A. (2006). Somatic Complaints in Primary Care: Further Examining the Validity of the Patient Health Questionnaire (PHQ-15). Psychosomatics, 47(5), 392-398.

Kocalevent, R., Hinz, A., & Brähler, E. (2013). Standardization of a screening instrument (PHQ-15) for somatization syndromes in the general population. BMC Psychiatry, 13(1).

De Vroege, L., Hoedeman, R., Nuyen, J., Sijtsma, K., & van der Feltz-Cornelis, C. (2012). Erratum to: Validation of the PHQ-15 for Somatoform Disorder in the Occupational Health Care Setting. Journal Of Occupational Rehabilitation, 22(4), 590-590.

Watson, D., & Pennebaker, J. W. (1989). Health complaints, stress, and distress: Exploring the central role of negative affectivity. Psychological Review, 96, 234–254


Children’s Somatization Inventory (CSI-24)

The Children’s Somatization Inventory (CSI-24; Walker, Garber, & Greene., 1991) is a revised version from the original Children’s Somatization Inventory conceptualized by Walker and Colleagues in 1991. The original version of the CSI consisted of 35 items corresponding with symptoms consistent with the DSM-III-R criteria for Somatization Disorder. In 2009 the CSI was reviewed and a shorter version, consisting of 24 items, was created. The revised version was the result of eliminating 11 items that were rarely endorsed and had low item-total correlations.
There has been some controversy over the factorial structure of the instrument. Factorial Analysis of the CSI-24 found it not to be considered a strictly uni-dimentional instrument as although its items load onto one factor, with positive standardized factor loadings, the fit was found to be poor (Walker, Garber, & Greene., 1991). Further research has suggested that a 6-item one factor instrument demonstrates a better fit and adequate psychometric properties (Orgiles & Espada, 2013).
The inventory was conceptualized using a predominantly Caucasian clinical sample with a primary complaint of chronic abdominal pain, but this instrument has since been found a valid measure in community populations (Lavigne, Saps, & Bryant., 2012) and other cultures (Orgiles & Espada, 2013)
Psychometric properties
The CSI-24 has been found to correlate highly with the CSI-35 (– r=.99, p<.001; Walker et al., 2009) and hence has been considered a refined version of the original measure. The CSI-35 has been examined in numerous studies and has evidence of high concurrent and convergent validity (r>.4) with other measures of somatization, and good support from a number of studies for it’s construct validity.

  • Internal Consistency alpha .84-.92 (Cerutti et al., 2017; Lavigne, Saps, & Bryant., 2012)
  • Validity for the CSI-24 has been demonstrated in its correlation as expected with measures of anxiety, depression, functional impairment and quality of life (Lavigne, Saps, & Bryant., 2012)
  • Scores for older children and females tend to be higher with a low to medium effect size (d=0.52) (Walker et al., 2009).
  • Parent report has been shown to be lower in school samples and higher in clinical samples than the associated child report (Cerutti et al., 2017).


Cerutti R., Spensieri V., Valastro C., Presaghi F., & Guidetti V. (2017). A comprehensive approach to understand somatic symptoms and their Impact on emotional and psychosocial functioning in children. PLoS ONE, 12(2).

Laird K., Sherman A., Smith C., & Walker L. (2015). Validation of the abdominal pain index using a revised scoring method. Journal Pediatric Psychology, 40(5). Doi:10.1093/jpepsy/jsu118

Lavigne, S.L., Saps, M., & Bryant, F.B. (2012). Reexamining the factor structure of somatization using the children’s somatization inventory (CSI-24) in a community sample. Journal of Pediatric Psychology, 37, 914-924. Doi:10.1093/jpepsy/jss060

Orgiles, M. & Espada, J. P. (2014). Spanish version of the children’s somatization inventory: factorial structure and psychometric properties in a community sample. International Journal of Behavioural Medicine, 21, 556-560. Doi:10.1007/s12529-013-9335-9

Walker, L. S., Beck, J. E., Garber, J., & Lambert, W. (2009). Children’s somatization inventory: Properties of the revised form (CSI-24). Journal of Pediatric Psychology, 34, 430-440.

Child Attitude Toward Illness Scale (CATIS)

The CATIS is 13-item self-report measure developed in the United States. It was originally designed for children with epilepsy, but has been validated for use with asthma, and is considered applicable to a range of chronic conditions because of its adaptability and strong validity. The original development study validated the CATIS for 8 -12 year olds. Subsequent studies have demonstrated the CATIS validity for use with 11 – 17 years (Heimlich et al., 2000), and 8 – 22 year olds (Ramsey et al., 2016).

The CATIS structure allows the administrator to adjust each item to correspond with child/adolescent’s specific illness. For example:

How good or bad do you feel it is that you have [insert specific illness]?

Each items is rated on a 5-point scale

Very Good – A Little Good – Not Sure – A Little Bad – Very Bad.

To score the CATIS items are summed and divided by 13, after the necessary reverse scores are calculated. Higher scores indicate a more positive attitude towards the condition. The possible ranges of score is 13 to 65.

Why was the scale developed?

Research has shown that young people who could focus on the positive aspects of their condition had more favourable treatment outcomes and recovery from illness compared to those who did not. Research has also shown that children who viewed themselves as different and less worthy than their peers because of their illness were likely to become withdrawn, socially isolated, have poor self-concept, lowered academic functioning, and behavioural problems. The CATIS was developed to measure these favourable/unfavourable attitudes and was one of the first measures to directly ask children their attitudes about having a chronic condition.

There is strong evidence regarding high levels of internalised stigma across multiple health conditions. For people with a chronic illness, internalised stigma may manifest as:
feelings of disappointment and guilt for becoming ill, feelings of inferiority compared to others because of their illness, as well as low self-esteem and self-efficacy.

A more recent focus on Self-Management models for those with chronic conditions encompasses the development in people with chronic illness to develop skills to manage health behaviours, skills to manage illness in the context of everyday life. Also important is that patients develop understanding the interactive nature of these issues in the context of family, community, and healthcare settings. The negative cognitive appraisals of self and illness associated with internalised stigma (due to illness) can impact the success of self-management skill development. Young people may instead engage in maladaptive behaviours that impede treatment efficacy and worsen disease course.

CATIS Psychometric Properties
In the original scale development the internal reliability for the total scale had a coefficient alpha of .80. The test-retest was good with difference between the means at time 1 (M = 3.09, SD = 0.65) and time 2 (M = 3.30, SD = 0.75) being statistically significant t(47) = 3.1, p < .01.  Confirmatory factor analysis was carried out to confirm the single dimension of the scale. They used the goodness-of-fit (GFI) index which was considered better for assessing single factor and is a measure of its relative variance and covariance, was .86. The coefficient of determination was .53, and the t values testing the relationship between latent variables were all over 2.0. Lamda values ranged from .33 to .84 and these results supported the unitary construct of the scale.

A recent systematic review of the literature on internalised stigma instruments (Stevelink et al., 2012) assessed 21 scale development studies using a comprehensive quality criteria framework for psychometric properties, including: Content validity, internal consistency, criterion validity, construct validity, reproducibility, responsiveness, floor and ceiling effects, and interpretability. These criteria were applied by two or more independent raters and a consensus determined regarding the results. They found that the CATIS was one of two instrument that received the most positive ratings.

Even more recently there was systematic review of the literature on the CATIS (Ramsey et al., 2016). It confirmed the robust reliability and validity of the CATIS across different chronic illnesses. The review also highlighted the CATIS’ good generalisability, affordability and determined it was good for both research and clinical contexts. But they highlighted some limitations too. Because the CATIS is delivered in different settings and via different methods, adapted to different illnesses and ages, it has limited cross study utility. They also noted that there have been no studies looking at minimum cognitive capabilities required for the CATIS (for those with developmental delays or IDs), no cross-cultural comparison research, and sparse evidence for the CATIS’ predictive validity. The CATIS also has no norm because clinicians can use and interpret the findings as they see fit. They determined that, while it was a good and useful scale, more research would be advantageous.


Austin, J. K., & Huberty, T. J. (1993). Development of the child attitude toward illness scale. Journal of Pediatric Psychology18(4), 467-480.

Heimlich, T. E., Westbrook, L. E., Austin, J. K., Cramer, J. A., & Devinsky, O. (2000). Brief report: Adolescents’ attitudes toward epilepsy: further validation of the Child Attitude Toward Illness Scale (CATIS). Journal of Pediatric Psychology25(5), 339-345.

Ramsey, R. R., Ryan, J. L., Fedele, D. A., Mullins, L. L., Chaney, J. M., & Wagner, J. L. (2016). Child Attitude Toward Illness Scale (CATIS): A systematic review of the literature. Epilepsy & Behavior59, 64-72.

Stevelink, S. A. M., Wu, I. C., Voorend, C. G., & van Brakel, W. H. (2012). The psychometric assessment of internalized stigma instruments: A systematic review. Stigma Research and Action2(2).

Spence Children’s Anxiety Scale (SCAS)

The Spence Children’s Anxiety Scale (SCAS) developed by Spence (1998), is a self-report measure designed to assess the severity of anxiety symptoms in children relating to separation anxiety, social phobia, obsessive-compulsive disorder, panic agoraphobia, generalised anxiety and fears of physical injury. The major sample involved in the acquisition of normative data included 2,052 children, 8-12 years of age, recruited from primary schools in Brisbane, Australia. The scale was primarily developed as most child-report measures of anxiety fail to examine anxiety symptoms that relate to specific anxiety disorders, such as separation anxiety disorder. Secondly, most of the measures available are downward extensions of adult measures of anxiety and are based on the assumptions that childhood anxiety closely resembles adult anxiety (Spence, 1998).

The scale consists of 44 items which can be filled out by the child. Thirty-eight of the items reflect specific symptoms of anxiety, while 6 relate to positive, filler items to reduce negative response bias, such as, “I am the most popular amongst other kids my own age”. The scale is quick and easy to administer, taking only 10 minutes. Items are consistent with specific DSM-IV anxiety disorders. Participants are asked to rate the degree to which they experience a symptom on a 4-point frequency scale, Never, Sometimes, Often and Always. Sample items from the separation anxiety subscale include, “I worry about being away from my parents” and “I feel scared if I have to sleep on my own”. Sample items from the obsessive-compulsive subscale include, “I have to keep checking that I have done things right (like the switch is off, or the door is locked)” and “I have to do some things in just the right way to stop bad things happening” (Spence, 1998).

The total score may be computed from adding together all the subscale scores. The sub-scale scores are computed by adding the individual item scores on the set of items within that domain. Scores within one standard deviation (ie. a T-score of 10) above the mean on any dimension are regarded as being within the normal range on that dimension. A T-score of 60 is indicative of sub-clinical or elevated levels of anxiety. This justifies further investigation and confirmation of diagnostic status using clinical interview.

Confirmatory factor analysis demonstrates that the SCAS items load strongly upon the factors that they purport to measure. Internal consistency (reliability) for the total scale is extremely high (.92) confirming that the items of the scale are measuring the same construct. The internal consistency for the subscales is also acceptable, .82 (panic-agoraphobia); .70 (separation anxiety); .70 (social phobia); .60 (physical injury fears); .73 (obsessive-compulsive) and .73 (generalised anxiety). Test-retest reliability was examined in a sample of 344 children who were reassessed after 6-months after the initial data collection which showed a test-retest reliability coefficient of .60. This suggests reasonably high reliability over a 6-month period for the total score. Test-retest reliabilities were lower for the individual subscales, indicating children’s reports of anxiety symptoms tend to decrease after a six-month retest interval. The SCAS total score correlates significantly (.71) with the Revised Children’s Manifest Anxiety Scale (RCMAS).

Since the development of the SCAS a parent version (Nauta et al., 2004), a pre-school version (Spence, Rapee, McDonald, & Ingram, 2001) and an adolescent version (Spence, Barrett, & Turner, 2003) has been developed, validated and readily available. The SCAS is freely available and provides a measure of anxiety symptoms related to specific anxiety disorders. The SCAS is used in clinical contexts for both assessment and evaluation purposes. It is also used to identify children at risk of developing anxiety problems and for monitoring outcome intervention. The developers of the SCAS stipulate a diagnosis should be made with the addition of a structured clinical interview.


Nauta, M. H., Scholing, A., Rapee, R. M., Abbott, M., Spence, S. H., & Waters, A. (2004). A parent-report measure of children’s anxiety: psychometric properties and comparison with child-report in a clinic and normal sample. Behaviour Research and Therapy, 42(7), 813-839. doi: 10.1016/S0005-7967(03)00200-6

Spence, S. H. (1998). A measure of anxiety symptoms among children. Behaviour Research and Therapy, 36(5), 545-566. doi: 10.1016/S0005-7967(98)00034-5

Spence, S. H., Barrett, P. M., & Turner, C. M. (2003). Psychometric properties of the Spence Children’s Anxiety Scale with young adolescents. Journal of Anxiety Disorders, 17(6), 605-625. doi: 10.1016/S0887-6185(02)00236-0

Spence, S. H., Rapee, R., McDonald, C., & Ingram, M. (2001). The structure of anxiety symptoms among preschoolers. Behaviour Research and Therapy, 39(11), 1293-1316.