Study protocol for a systematic review of evidence for lifestyle interventions targeting smoking, sleep, alcohol/other drug use, physical activity, and healthy diet in people with bipolar disorder

People with mental illness have a reduced life expectancy of between 12 and 20 years compared to the general population [1, 2]. To date, much of the attention on this issue has focused on the increased risks of suicide in people with mental illness, which has been shown to account for about 20 % of the premature deaths in populations with a mental illness. Comparatively little attention has been paid to reducing the risk of physical conditions, which account for 80 % of excess deaths in psychiatric populations [2].

A particular focus on bipolar disorder (BD) is important. In BD, reduced life expectancy in comparison with the general population ranges from 11 to 20 years depending on the age of onset of the disorder [3]. The reasons for this disparity are complex and multi-faceted, involving genetic, biological, environmental, psychological, and social factors. Cardiovascular disease (CVD) diagnoses occur 6 years earlier for those with BD than for depression and 15 years ahead of the general population [4]. Many factors are attributed to this, including the significant and adverse effects of medication for BD, such as weight gain, metabolic syndrome, high cholesterol, hypertriglyceridemia, and other cardiometabolic problems [5]. Medications commonly prescribed in BD—anti-manic, antipsychotic, and antidepressant treatments—can negatively contribute through adverse side effects including weight gain, sedation, and disordered glucose tolerance [6]. In addition, the phases of BD mean that people can oscillate between intense periods of severe depression (with high risk of suicide) followed by intense periods of activity and irritability, masking a cycle of agitation, sleep, and physical exhaustion that can have a significant impact on confidence, self-efficacy, and health-related decisions [7]. Up to 65 % of people with BD report current tobacco use [8] and smoke at 2.6 times the rate of people with major depressive disorder (MDD) and 6.3 times more than the general population [9]. Smoking is independently associated with suicide risk, poorer response to treatment, and structural brain changes [10]. Physical inactivity has been identified as an independent predictor of premature mortality among people with BD and significantly increases their risk of CVD [11]. In a study of 1046 Australian women, poor diet quality was associated with twice the odds for BD [12]. In another study comparing 2032 participants with BD in the general population, having BD was associated with significantly poorer eating behaviors, including fewer daily meals and difficulty obtaining or cooking food, as well as increased appetite and caloric intake [13]. Complicating this and supporting an integrated approach, people at risk for one adverse health behavior are at greater risk for others [14]. There is often poor integration between mental health and physical health services internationally and well-documented concerns by people with mental illness using existing services, who report inequity of access to physical-health-related interventions and support [9]. Together, the periods of being unwell with a psychiatric illness, combined with side effects of many medications, may contribute to the inequality in physical wellness for clients with mental health issues and the general population.

In order to reduce the mortality gap between people with BD and the general population, greater understanding is required of how best to assist them and their clinicians to address the potentially modifiable lifestyle behaviors associated with this gap [15, 16]. Recently, the International Society for Bipolar Disorder (ISBD) developed consensus guidelines for monitoring of adverse side effects associated with commonly prescribed medications for the disorder [17]. The aim for these guidelines was to increase the acknowledgement and focus of health care providers on the physical health comorbidities germane to the management of BD [17]. Whilst this is critically important to the field, reducing the medication load for people with BD is just one strategy in addressing the mortality gap associated with the condition [18].

Of additional importance is to identify acceptable and effective interventions to improve the health outcomes of people with BD. There is increasing recognition of the importance of supporting all people with mental health problems to focus on lifestyle factors, such as smoking cessation, in addition to symptom management [19]. However, the nature of BD may mean that additional strategies are indicated to ensure safety and well as efficacy of these approaches. In contrast to other mental disorders, for example, regulation and structure are critical in BD for both symptom and lifestyle management. For example, when depressed, strategies need to encourage stimulation and activation; however, when manic, the opposite is true [20]. Key withdrawal symptoms of nicotine are insomnia and increased appetite, with standard behavioral programs recommending increased physical activity to cope with cravings, stress, and weight gain [21]. Sleep disturbance, increased appetite, and excessive exercise are all critical warning signs for a relapse to BD [22], and thus careful strategies for self-regulation may be a unique feature of any program that recommends changing these behaviors in people with BD. To date, no systematic review has examined these issues or the available evidence to support lifestyle management in people with BD specifically.

The objective of this review is to systematically identify and evaluate the literature regarding lifestyle behavioral interventions among people with BD. We aim to synthesize the available evidence regarding the management of unhealthy lifestyle behaviors and the promotion of health behaviors in people with BD, with regard to the impact of such interventions on health, symptoms, and related outcomes. Specifically, we aim to answer the following questions: