Background: The employment rate among people with severe mental illness has recently increased, though it is still low. The motivation to work appears to be an important role as an intermediate outcome measure in vocational rehabilitation programs. In addition, measuring the work motivation for people with severe mental illness appears to be essential to identify candidates who are likely to benefit and monitor candidates' motivation in a supported employment program. This study aimed to develop a new measure for assessing both intrinsic and extrinsic motivation to work among people with severe mental illness, as there are currently no well-established instruments of this kind.
Methods: A focus group interview and review of previous qualitative research were used to identify possible items for inclusion in the new scale. A provisional scale was constructed and further refined for content and format based on feedback from a researcher and also three peer workers with severe mental illness. The resulting provisional 38-item version of the scale was completed by 136 respondents with severe mental illness, and we performed exploratory factor analysis to identify latent constructs within the new measure. The finalized scale was analyzed for test-retest reliability, internal consistency, and convergent validity.
Result: An exploratory factor analysis yielded a four-factor scale with 23 items. The finalized 23 items had high internal consistency (Cronbach's alpha = 0.91) and relatively high test-retest reliability (ICC = 0.83). The four subscales had fair internal consistency (Cronbach's alpha ≥ 0.69) and good test-retest reliability (ICC ≥ 0.61). Convergent validity was weakly supported by the significant positive correlations with the overall question on motivation to work (r ≥ 0.19, p < 0.01). Besides these correlations, only the "Pressure from others" subscale was negatively and significantly correlated with the negative symptoms evaluated using the Positive and Negative Syndrome Scale (r = -0.18, p = 0.04).
Conclusions: This study used factor analysis to develop a new multidimensional scale assessing motivation for competitive employment among persons with severe mental illness. The scale showed acceptable levels of reliability and factor-based and convergent validity. The new measure can be used for measuring the motivation for competitive employment among people with severe mental illness, and it would be useful to identify candidates who are likely to benefit from a certain supported employment program, and to monitor interim progress of the state of participants' motivation in a program.