Moderating effects of age on associations between exercise self-efficacy and physical activity in women with psychosis in Hong Kong

Abstract

Background: Physical activity (PA) can improve the clinical symptoms, physical health, and functional outcomes of patients with psychosis. This study aimed to investigate the moderating effects of age on the associations between exercise self-efficacy (ESE) and PA in women with psychosis.

Methods: Data from 38 women with psychosis (mean age, 37.5±13.2 years) who participated in a community mental health project in Hong Kong were analysed. Psychotic symptoms were evaluated using the Scale for the Assessment of Positive Symptoms and the Scale for the Assessment of Negative Symptoms. Levels of PA were determined using the self-report International Physical Activity Questionnaire-Long Form. ESE was assessed using a self-report instrument. The moderating effects of age on associations between ESE domains and physical activity levels were assessed.

Results: Age was correlated with moderate-intensity PA (r= 0.51, p = 0.007) and total PA (r= 0.52, p = 0.002). The ESE ‘must exercise alone’ domain was correlated with moderate-intensity PA (r= 0.17, p = 0.009) and total PA (r= 0.15, p = 0.04). The ESE ‘resistance from others’ domain was correlated with moderate-intensity PA (r= 0.0003, p = 0.03). No significant correlations were observed between other PA variables and other ESE domains. Among women with psychosis, age was a moderating factor in the association between moderate-intensity PA and ESE, particularly in domains of ‘must exercise alone’, ‘inconvenience to exercise’, and ‘resistance from others’.

Conclusion: Among women with psychosis, ESE domains of ‘must exercise alone’, ‘inconvenience to exercise’, and ‘resistance from others’ as well as overall ESE were significantly associated with moderate-intensity PA in older age group only. Age-specific strategies should be applied when designing interventions to increase PA levels in this population.

Introduction

Psychotic disorders can result in unfavourable functional outcomes and increased global burden of disease.^1,2They are also associated with a reduced life expectancy of up to 20 years,³and the mortality gap has increased over the past 3 decades.⁴Early intervention can improve and maintain early outcomes and long-term prognosis.^5,6However, a large proportion of patients still experience poor functioning despite receiving early intervention services.⁷Poor outcomes are associated with physical inactivity, residual psychotic symptoms, and impaired cognitive function.⁸Although antipsychotic medications can alleviate psychotic symptoms, their efficacy for functioning is limited, and they can cause adverse metabolic effects.⁹

Exercise and non-pharmacological interventions are increasingly used to improve outcomes.¹⁰Exercise interventions, in particular, have transdiagnostic efficacy and cost-effectiveness for various psychiatric conditions.^11,12They are effective in improving cognitive, functional, and symptomatic outcomes as well as reversing some neurobiological changes, such as hippocampal volume, in psychotic disorders.¹³Combining an exercise intervention with cognitive training can effectively enhance the thickness of the fronto-cingulate cortex, thereby reducing the progressive neural degeneration that occurs in the early stages of schizophrenia.¹⁴Additionally, aerobic fitness is positively correlated with volumes of grey matter and white matter in the right hippocampus, parahippocampal region, and other cerebellar regions in individuals with a first episode of psychosis.¹⁵The benefits of exercise interventions have also been observed in Asian populations.^16,17However, self-efficacy (motivation and sustainability) in engaging exercise is a challenge for psychiatric patients.^18,19

Self-efficacy in exercise refers to one's belief in their ability to perform exercise.²⁰It is a key factor in determining the level of physical activity (PA) in individuals with psychosis.^18,19Age is associated with self-efficacy and exercise levels in obese adults.²¹Middle-aged and older adults exhibit higher levels of exercise self-efficacy (ESE) but lower levels of exercise, compared with younger adults.²²Thus, age-specific levels of self-efficacy should be considered when developing interventions to encourage PA.²²By determining the role of age in noncompliance with PA, therapists can better understand patient needs so as to implement targeted behavioural techniques and enhance PA habits.

Women's participation in exercise depends on self- efficacy.²³In patients with psychosis, women tend to have a later onset age, and their aetiology has a stronger association with dysregulation in psychosocial factors. Women commonly take on caregiving responsibilities within their families; their well-being may affect the health of care recipients. The findings of this study may help healthcare providers to develop more personalised interventions and strategies that encourage regular PA and improve overall well-being and health outcomes among women with psychosis. In this study, we aimed to determine whether age is associated with ESE and PA level among women with psychosis.

Methods

The present study was part of the Jockey Club Mental Wellness Project for Women.^16,24The project's goal is to implement early detection and intervention for mental disorders to improve clinical outcomes, particularly for women with psychosis. Women aged 18 to 64 years with a diagnosis of non-affective psychotic disorder (based on DSM-5) who were suitable for exercises were recruited from a psychiatric outpatient clinic at a public hospital in Hong Kong or were referred by community workers. Data from 38 women with psychosis (mean age, 37.5±13.2 years) were analysed.

Psychotic symptoms were evaluated using the Scale for the Assessment of Positive Symptoms²⁵(SAPS) and the Scale for the Assessment of Negative Symptoms²⁶(SANS). The SAPS has 30 items in four domains: hallucinations (α = 0.75), delusions (α = 0.67), bizarre behaviour (α = 0.31), and positive formal thought disorder (α = 0.86), whereas the SANS has 20 items in five domains: affective flattening or blunting (α = 0.83), alogia (α = 0.80), avolition-apathy (α = 0.27), anhedonia-asociality (α = 0.77), and attention disturbance (α = 0.47). Each item on both scales is measured using a 6-point Likert scale from 0 (none) to 5 (severe); higher scores indicate more severe levels of positive or negative symptoms.

Levels of PA were determined using the self-report International Physical Activity Questionnaire-Long Form²⁷(IPAQ-L) in terms of employment, transportation, household chores and gardening, and recreational PA; intensity is categorised into light (such as walking), moderate, and vigorous, based on metabolic equivalent of task (MET) minutes per week (min/week). For instance, 1 minute of light-, moderate-, and vigorous-intensity PA is equal to 3.3, 3-6, and 8 MET, respectively. The frequency and duration of specific activities in the week prior to the assessment were recorded.

ESE was assessed using a self-report instrument,²⁸which comprises 18 items in six domains: negative affect (α = 0.90), excuse-making (α = 0.83), must exercise alone (α = 0.95), inconvenient to exercise (α = 0.65), resistance from others (α = 0.87), and bad weather conditions (α = 0.90). Each item is measured using a 5-point Likert scale from 1 (not at all confident) to 5 (completely confident); higher scores indicate greater confidence in dealing with obstacles to exercise.

Statistical analyses were conducted using Rversion 4.3.1. Associations between ESE, age, and PA levels were determined using Spearman correlation analyses. Moderation analyses were performed using the interactionpackage in R. Age was a moderator, whereas PA level variables were regressed on each ESE domain in separate models. Psychotic symptom variables that were associated with PA levels (ie, hallucinations, affective flattening or blunting, and alogia) were added to the regression models as covariates. The sim_slopesfunction was used to analyse and visualise conditional simple slopes in the interaction models. The contribution of the interaction term to the variance explained by the independent variables was examined using hierarchical linear regression.

Results

The 38 women with psychosis exhibited severe delusional symptoms, mild-to-moderate symptoms of hallucination and positive formal thought disorders, and minimal symptoms of bizarre behaviour. They also exhibited severe symptoms of affective flattening or blunting, moderate symptoms of anhedonia-asociality, mild symptoms of alogia and avolition-apathy, and questionable symptoms of attention disturbance.

In the week prior to the assessment, participants reported a mean PA level of 3228.59 MET-min, which included 1201.93 MET-min of light-intensity PA, 1386.65 MET-min of moderate-intensity PA, and 640.00 MET-min of vigorous-intensity PA.

Age was correlated with moderate-intensity PA (r= 0.51, p = 0.007) and total PA (r= 0.52, p = 0.002). The ESE ‘must exercise alone' domain was correlated with moderate-intensity PA (r= 0.17, p = 0.009) and total PA (r= 0.15, p = 0.04). The ESE ‘resistance from others' domain was correlated with moderate-intensity PA (r= 0.0003, p = 0.03). No significant correlations were observed between other PA variables and other ESE domains.

The ‘must exercise alone' domain [x] age interaction term was significant (estimate = 23.29, standard error [SE] = 6.98, p = 0.002, ΔR²= 0.168). The unstandardised simple slope for moderate-intensity PA was -136.34 (SE = 149.12, p = 0.37) among participants aged 1 standard deviation (SD) below the mean age, 166.71 (SE = 90.82, p = 0.08) among participants aged within 1 SD of the mean age, and 469.77 (SE = 103.67, p [lesser than] 0.001) among participants aged 1 SD above the mean age (Figure 2a). The ‘inconvenient to exercise' domain [x] age interaction term was significant (estimate = 31.53, SE = 11.08, p = 0.008, ΔR2 = 0.149). The unstandardised simple slope for moderate-intensity PA was -251.12 (SE = 215.79, p = 0.25) among participants aged 1 SD below the mean age, 159.15 (SE = 129.68, p = 0.23) among participants aged within 1 SD of the mean age, and 569.41 (SE = 169.25, p [lesser than] 0.001) among participants aged 1 SD above the mean age (Figure 2b). The ‘resistance from others' domain [x] age interaction term was significant (estimate = 27.18, SE = 8.18, p = 0.002, ΔR²= 0.179). The unstandardised simple slope for moderate-intensity PA was -264.26 (SE = 183.77, p = 0.16) among participants aged 1 SD below the mean age, 89.40 (SE = 109.43, p = 0.42) among participants aged within 1 SD of the mean age, and 443.06 (SE = 113.33, p [lesser than] 0.001) among participants aged 1 SD above the mean age (Figure 2c). The overall ESE [x] age interaction term was significant (estimate = 4.38, SE = 2.07, p = 0.04, ΔR²= 0.091). The unstandardised simple slope for moderate-intensity PA was -27.42 (SE = 42.20, p = 0.52) among participants aged 1 SD below the mean age, 29.56 (SE = 25.74, p = 0.26) among participants aged within 1 SD of the mean age, and 86.55 (SE = 31.52, p = 0.01) among participants aged 1 SD above the mean age (Figure 2d).

Discussion

In the present study, confidence in one's ability to exercise independently (‘must exercise alone' domain) and confidence in overcoming resistance from others (‘resistance from others' domain) were associated with increased engagement in moderate-intensity PA. These associations were dependent on the participant's age. In addition, confidence in overcoming exercise inconvenience barriers (‘inconvenience to exercise' domain) and overall ESE, which were not initially associated with moderate- intensity PA, were associated with the older age group. The association between confidence in one's ability to exercise independently and total PA was not dependent on the participant's age. Indeed, the post-hoc analysis suggested that the association became non-significant after accounting for age and negative symptoms of affective flattening or blunting and alogia. Psychotic symptoms, particularly negative symptoms of affective flattening or blunting and alogia, affect levels of PA.²⁹No associations were observed between PA levels and other ESE domains including negative affect, excuse-making, and bad weather conditions. These findings underscore the effects of an individual's beliefs and confidence in PA on PA levels. Targeted strategies can be used to assist women with psychosis to overcome real-life barriers to PA, ultimately leading to improved adherence to exercise.

Self-efficacy is predictor for engagement and continuation of PA among older people (but not younger people).^21,22Exercise intentions of older people are more influenced by both perceived risk and result expectancies, compared with younger adults.²²Younger people tend to view themselves as less prone to health problems, but older adults perceive themselves as more susceptible to health problems, thereby having stronger intention and dedication to exercise. Strategies to promote PA among older adults may aim at enhancing self-efficacy. Methods to promote exercise include performing exercises in a safe environment, recalling previous successful performances, and observing others to perform exercise.³⁰Controlling expectations regarding the positive effects of exercise can affect health, social interactions, and other desirable results.³¹Individuals who are content with the initial goals are more inclined to maintain a consistent exercise routine.³²

In women, moderate-intensity PA primarily encompasses housework or work-related tasks (Table 2). This could explain the positive correlation between moderate-intensity PA and age, as older women are generally more involved in housework. Although ESE may not align perfectly with that required for daily chores or work-related activities, ESE was correlated with these work-related tasks, which are typically driven by role-related responsibilities such as homemaking. Women with higher ESE were more inclined to engage in housework, possibly with increased frequency.

The ‘must exercise alone' domain indicates the confidence to participate in PA without a partner. Ageing can lead to physiological and psychological changes in terms of objective and subjective physical health, health behaviours, and psychological influences on health behaviours. Older people generally have more time and make greater efforts to maintain their health as a primary goal,³³given their perceived vulnerability to illness, compared with younger adults.³⁴Their motivation to engage in regular PA to improve health outcomes may surpass the enjoyment of socialising with others. Furthermore, perception of and reaction to a particular situation depend on life experiences and self-regulation capabilities. Self-regulatory ability refers to ability to manage behaviour based on internal goals and limitations, as well as ability to control their thoughts and actions.³⁵Self-regulatory ability was developed through various experiences and adopt specific practices. Older people are more able to evaluate their self-efficacy and regulate and implement their thoughts and actions. In contrast, younger adults may lack the necessary experience and self-regulatory skills to execute their intentions, particularly those with psychosis, which are associated with impaired self-regulation.³⁶Although self-efficacy is associated with intention to exercise, the actual health behaviours can be influenced by numerous other factors.

Among women with psychosis, age moderated the associations between moderate-intensity PA and ESE, specifically the domains of ‘resistance from others' and ‘inconvenience to exercise'. Resistance from others can be viewed as a social force that either promotes or inhibits exercise habits, particularly when it originates from someone who is significant in their life. Three issues are covered in this domain: (1) my friend does not want me to exercise; (2) my significant other does not want me to exercise; and (3) I spend time with friends or family who do not exercise. Older adults may perceive PA as a health-related behaviour that improves their well-being,³⁷whereas younger people may consider PA a recreational activity influenced by social factors such as family and friends. Social support plays a crucial role in determining PA behaviour.³⁸The health promotion model explains how people interact with their interpersonal and physical environments for favourable health behaviours. This model considers social factors such as family and friends when initiating healthy behaviours. However, the influence of social factors changes throughout people's life. Social networks typically grow during young adulthood, a phase marked by exploration and establishment of new connections to meet emotional needs, and then decrease in size during later stages of adulthood.³⁹These changes may affect the utilisation of social resources to attain behavioural changes.

This study has several limitations. A cross-sectional design was used; thus, causality between ESE and PA levels cannot be deduced. Furthermore, the small sample size may lead to insufficient statistical power and a large margin of error. The use of the self-report IPAQ-L for evaluating PA levels may be subject to both systematic and random errors; the IPAQ-L may not accurately capture PA levels in patients with psychosis who have recall bias owing to difficulties in concentration and memory.

Our findings that age had moderating effects on associations between ESE and PA levels underscore the importance of implementing age-specific strategies to optimise PA levels in women with psychosis. Forming positive expectations for exercise, providing targeted support (group exercise) to enhance social connections, and offering family psychoeducation to foster emotional support may help women to overcome real-world challenges and increase their commitment to exercise. Gender affects behaviours because of societal norms and stereotypes. Women are more likely to report that emotions play a significant role in their decision-making process, whereas men are more focused on goals or objectives.⁴⁰Future research should examine how age and sex differences affect social-cognitive factors such as self-confidence, self-control, social support, external influences, outcome expectations, and perceived risk.

Conclusion

Among women with psychosis, ESE domains of ‘must exercise alone', ‘inconvenience to exercise', and ‘resistance from others' as well as overall ESE were significantly associated with moderate-intensity PA in older age group only. Age-specific strategies should be applied when designing interventions to increase PA levels and overall well-being in this population. For younger women with psychosis, interventions should focus on providing exercise opportunities and social support, such as family education and psychoeducation, to overcome emotional barriers. For older women with psychosis, interventions should focus on enhancing ESE.

Contributors

All authors designed the study, acquired the data, analysed the data, drafted the manuscript, and critically revised the manuscript for important intellectual content. All authors had full access to the data, contributed to the study, approved the final version for publication, and take responsibility for its accuracy and integrity.

Conflicts of interest

As editors of the journal, YNS, HMEL, LMCH, KWS Chan, and EYHC were not involved in the peer review process. Other authors have disclosed no conflicts of interest.

Funding/support

This study was funded by the Hong Kong Jockey Club

Charities Trust (grant number: 2017/0104).

Data availability

All data generated or analysed during the present study are available from the corresponding author on reasonable request.

Ethics approval

This study was approved by Kowloon West Cluster Research Ethics Committee (reference: KW/EX-16-041(96-23)). The participants provided written informed consent for all treatments and procedures and for publication.

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