Depression severity and concentration difﬁculties are
independently associated with HRQOL in patients with unipolar
the ILDE Study Group
Accepted: 9 May 2017 / Published online: 13 May 2017
Ó Springer International Publishing Switzerland 2017
Purpose Cognitive impairment is a core feature of major
depressive disorder (MDD), and dysfunctions in this area
strongly contribute to MDD-associated disability. Whether
cognitive impairment has an independent clinical course
and a unique impact on HRQOL is still debated. We sought
to characterize the relationship between depression severity
and HRQOL, evaluating the burden of concentration dif-
ﬁculties on HRQOL.
Methods Six hundred ninety-two patients with unipolar
depressive disorders recruited in 19 Italian centers answered
a self-administered survey (SF-12 questionnaire, socio-de-
mographic information). A psychiatrist completed a stan-
dardized data collection form encompassing a depression
severity scale (MADRS) and clinical information.
Results There was a strong graded association between the
severity of depressive symptoms and both the physical
= 0.13; p \ 0.01) and mental (x
= 0.34; p \ 0.01)
SF-12 domains. Additionally, we observed a strong asso-
ciation between concentration difﬁculties and all HRQOL
outcomes independent of other symptoms of depression
and robust to adjustment for possible confounders.
Conclusions Our data corroborate previous ﬁndings sug-
gesting that cognitive impairment is a feature of unipolar
depressive disorders partially independent of the severity
of other symptoms, and may represent a speciﬁc target of
therapy with a strong impact on patients’ functioning and
quality of life.
Keywords Unipolar depressive disorder Á HRQoL Á
Cognitive impairment Á Depression severity Á SF-12 Á
Depression is a primary determinant of years lost due to
disability accounting for 24.5% of all disability-adjusted
life years (DALYs) due to mental, neurological, and sub-
stance use disorders [1, 2]. Prevalence of lifetime depres-
sion ranges from 7.6 to 16.6% across countries [3, 4] and
the economic burden has been estimated in 210 billion
dollars per year in the USA only .
There is evidence that major depressive disorder (MDD)
has a detrimental impact on functional impairment and
health-related quality of life (HRQOL) compared to the
general population and other medical conditions [6–10].
Additionally, previous studies have found that depression
severity is strongly associated with functional disability
Cognitive impairment is a core feature of MDD ;
research has extensively demonstrated association of major
depression with cognitive disturbances, such as impairment
Centers participating in the ILDE Study Group are listed in Appendix.
Electronic supplementary material The online version of this
article (doi:10.1007/s11136-017-1595-4) contains supplementary
material, which is available to authorized users.
& A. Fattori
Department of Clinical Sciences and Community Health,
University of Milan, Milan, Italy
Outcomes Research Consulting, Milan, Italy
Department of Clinical and Experimental Medicine,
University of Foggia, Foggia, Italy
Department of Mental Health, ASL3, Genoa, Italy
Depression Unit, Neuroscience Department, Fatebenefratelli
Hospital, Milan, Italy
Qual Life Res (2017) 26:2459–2469