
nutrition may be important for happiness and psychological
health in people [9, 10].
Well-being is an attempt to promote the manifest for
realization of the one’s talents and abilities [11]. Psycho-
logical well-being is very important to correlate well-being
with excess weight in people and individual with obesity is
often associated with impairing of psychological well-be-
ing [12]. These findings suggest that self-efficacy, happi-
ness and psychological well-being are important predictors
of the adoption and maintenance of weight control
behaviors during treatment and greater confidence in abil-
ity to control eating behavior is associated with long-term
maintenance of lost weight after SG. So far, no research
has investigated these variables simultaneously; thus, the
purpose of this study was to evaluate the relationship
between self-efficacy, happiness and psychological well-
being after SG.
Materials and methods
Participants
One hundred patients that underwent bariatric surgery for
their morbid obesity from 2017 to 2019 were asked to
participate in this study. The patients’ mean age was
37.65 years (SD = 10.59). In our study, 15.4% of partici-
pants were men and 84.6% were women. They were asked
to fill questionnaires 12 months after SG. The average time
for the filling out research questionnaires was about
30 min. Data were analyzed by Pearson correlation coef-
ficient and regression tests using SPSS (ver. 16) software.
Descriptive data were also reviewed with mean and stan-
dard deviations.
Measurements.
General self-efficacy questionnaire
To assess the general self-efficacy, we used ten-item scale
developed and validated by Sherer and Maddux [13] that
measured three aspects of behavior: desire to initiate
behavior, desire to expand efforts to complete the task and
resistance in dealing with obstacles. Respondents were
asked to report on the extent to which they had experienced
general self-efficacy. Responses were made on a four-point
Likert-type scale ranging from 1 = ‘‘absolutely untrue’’ to
4 = ‘‘absolutely true.’’ All items had factor loadings
ranging from 10 to 40. In Shere et al. study, the Cronbach’s
alpha was 0.85 and its validity was 0.86 for this scale [13].
High reliability, stability and construct validity of the
GSES scale are confirmed in earlier studies [14, 15]. In our
study, Cronbach’s alpha was 0.87.
Happiness questionnaire
To assess happiness, we used Oxford happiness scale (29
items) developed by Argyle and Lou [16]. Responses were
made on a four-point Likert-scale ranging from
0 = ‘‘completely opposed,’’ 1 = ‘‘opposed,’’ 2 = ‘‘agree’’
and 3 = ‘‘completely agree.’’ According to Oxford happi-
ness scale, the highest grade is 87 and lowest is 0 that
denotes the lack of happiness of patients. Alpha coefficient
was 0.90 [16, 17]. The Cronbach’s alpha index for this
measure was 91%, according to previous specific validity
studies in Iran [18]. Cronbach’s alpha in this study was
0.95.
Psychological well-being questionnaire
To assess psychological well-being, we used 18-item scale
of the Ryff psychological well-being scale that was
designed by Ryff [19]. Reliability coefficient was assessed,
and the retest method for the whole scale was 0.82.
Responses were based on a six-point Likert-type scale
ranging from 1 = ‘‘completely opposed,’’ 2 = ‘‘somewhat
disagree,’’ 3 = ‘‘opposed,’’ 4 = ‘‘agree,’’ 5 = ‘‘somewhat
agree’’ and 6 = ‘‘completely agree.’’ The correlation
between the short version of the psychological well-being
scale and the Ryff scale was fluctuating from 0.7 to 0.89
[20]. Bayani et al. [21] reported the reliability coefficient
by using the retest of psychological well-being scale (0.82),
and the subscales of self-acceptance, positive relationships
with others, autonomy; environmental dominance, targeted
life and personal growth were 0.71, 0.78, 0.70, 0.77, 0.78
and 0.77, respectively. Cronbach’s alpha in our study was
0.68.
Results
In order to evaluate the prediction of self-efficacy after SG,
regression analysis was used on happiness and psycho-
logical well-being. The age range was between 18 and
66 years old. The patients mean weight was reduced after
surgery from 121.41 to 90.24 kg. (Mean of BMI decreased
from 43.22 to 33.16.) The results of happiness, self-efficacy
and psychological well-being 12 months after surgery are
shown in Table 1. The regression analysis results of self-
Table 1 Mean and standard deviation of psychological well-being,
happiness and self-efficacy after SG
Psychological well-being Happiness Self-efficacy
70.91 ± 11.49 55.21 ± 15.11 31.03 ± 4.44
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