17.1: What is Severe Mental Illness?

Many mental health conditions can be considered as severe for the people who experience them, as well as their support networks. However, the phrase severe mental illness refers to a specific group of mental health disorders including schizophrenia, bipolar disorder, and major depressive disorder, that significantly impact a person’s functioning in daily life and in some cases, may be associated with a distorted sense of reality. Severe mental illness can also be defined by the length of duration and the subsequent disability it has on a person’s life.

Here we outline some severe mental illness diagnoses as well as common symptoms, to provide a brief context for how physical health can be subsequently impacted and the role that physical activity can provide as part of a treatment plan. Examples of severe mental illnesses are schizophrenia, bipolar disorder, and major depressive disorder.

17.1.1. Schizophrenia

This complex disorder can impact a person’s mental health, physical health, and cognitive function. Lifetime prevalence for developing schizophrenia affects approximately 1% of the population (Kessler et al., 2005). It can produce intense periods of psychosis and negatively impact long-term functioning. Symptoms of schizophrenia are generally divided into three broad categories: positive symptoms, such as hallucinations or delusions, which are “added” to someone’s experience; negative symptoms, describing loss of experience, which can include social withdrawal, decreased enjoyment in activities, and reduced motivation; and finally, cognitive impairment, which is associated with changes in memory, attention, cognition, and executive function.

17.1.2. Bipolar Disorder

Bipolar disorder significantly impacts a person’s mood or affect and is characterized by periods of elevated moods or mania where people can present with increased energy, impulsivity, and reduced sleep. This can be followed with interchanging significant depressive episodes. The lifetime prevalence for developing this disorder is approximately 0.6% (Merikangas et al., 2010). Bipolar disorder can also include experiences of psychosis.

17.1.3. Major Depressive Disorder

Major depressive disorder is a prevailing and debilitating mental health condition and is one of the leading contributors to the global burden of disease. Major depressive disorder has approximately a 16% lifetime prevalence (Kessler et al., 2005) and accounts for 8.2% of the global years lived with disability in 2010 (Ferrari et al., 2013). Symptoms that are commonly experienced with major depressive disorder include persistent low mood and reduced interest in activities or hobbies, in addition to poor sleep, changes in appetite, and in some cases suicidal ideation. People living with major depressive disorder may also experience declined social functioning, such as difficulties with maintaining relationships and employment.

17.1.4. Psychosis

Psychosis describes a group of symptoms which are experienced by people with a psychotic disorder (e.g., schizophrenia). Symptoms of psychosis impact an individual’s thoughts and perceptions and are defined by a distortion in a person’s perception of reality. This can include senses including smell, thoughts, visions, tactile sensations, and beliefs. Most people that develop a psychotic disorder will experience symptoms prior to 25 years of age (Morgan et al., 2012). It is important to recognize that psychosis is a symptom of a mental disorder, rather than an illness itself. While we do not fully understand how psychosis develops, various factors can contribute to a psychotic episode including family history, mental or physical illness, extreme stress, trauma, and substance use.

Psychosis, which is not to be confused with psychoticism, typically develops in youth or adolescence and is typically accompanied by marked decline in functioning, changes in behaviour including difficulties concentrating, sleep disturbances, withdrawing from social supports, disorganized speech, depression, and anxiety. The first episode of psychosis or FEP is when someone experiences psychosis for the first time. Symptoms of psychosis can include hallucinations, delusions, and disordered thinking and cognition.

17.1.4.1. Hallucinations

Hallucinations occur when someone experiences sensations inconsistent with reality. Hallucinations are most commonly auditory (e.g., hearing voices), but may also be visual (e.g., seeing shapes or figures), in tactile form (e.g., experiencing sensations or feelings), olfactory (e.g., smelling odors that are not present), or gustatory (impacting taste).

17.1.4.2. Delusions

Delusions refer to beliefs that are not based on reality and may impact individual actions or functioning. Delusions can vary depending on the individual and the illness. Delusions may, for example, be paranoid, grandiose, somatic, persecutory, or romantic in nature.

17.1.4.3. Disordered Thinking and Cognition

Speech and thought patterns may become confused and mixed-up. People may experience problems with memory and other cognitive process (e.g., concentration). This can result in people behaving or communicating differently.

17.1.5. Early Psychosis and Ultra-High Risk

Those with at-risk mental states or ultra-high risk refers to a group of individuals who are at high risk of developing psychosis; this is often referred to as the prodromal period (Galletly et al., 2016). To meet criteria for ultra-high risk, individuals may exhibit a number of factors including genetics or family history, the presence of some brief limited intermittent psychotic symptoms (BLIPS), or attenuated (sub-threshold) symptoms of psychosis (Yung et al., 2005). Youth in these categories will be diagnosed by an experienced mental health clinician using a validated assessment tool (Nelson, 2014). Early interventionis a critical period, for both physical and mental health outcomes, to improve the future well-being for youth experiencing psychosis for the first time (Shiers et al., 2014).

17.1.6. Health Risks for People with Severe Mental Illness

People living with severe mental illnesses face high rates of premature mortality compared to members of the general population (Baxter et al., 2016). The major contributor to this early mortality is poor physical health, often linked to non-communicable diseases. In particular, people with severe mental illness have a 1.4–2.0x increased risk of developing cardiometabolic diseases compared to people without mental illness (Firth et al., 2019). This accounts for approximately 1/3^rd of the premature mortality (John et al., 2018). This is associated with higher rates of diabetes, obesity, metabolic syndrome, and respiratory complications. Additionally, people living with severe mental illness face high levels of disability, with schizophrenia being the 12^th largest cause of years lived with a disability worldwide (Vos et al., 2017).

17.1.6. Impact of Modifiable Risk-Factors

People living with severe mental illness are at high risk of cardiometabolic disease impacted, in part, by multifactorial lifestyle risk factors including cigarette smoking, physical inactivity, consuming poor diets, and experiencing poor sleep (Firth et al., 2020).

17.1.6.1. Cigarette Smoking

People with severe mental illness are more likely to smoke cigarettes, with approximately 1 in 2 people a smoker compared to approximately 1 in 10 people in the general population (Gilbody et al., 2015). People with severe mental illness are more dependent on nicotine and have increased difficulty engaging in smoking cessation programs compared to those in the general population (Ashton et al., 2013; Malpass et al., 2009).

17.1.6.2. Physical Inactivity

People with severe mental illness are less likely to be physically active than the general population and struggle to meet recommended physical activity guidelines of a minimum of 150 minutes of moderate-intensity physical activity per week (Vancampfort, Firth, et al., 2017). There are differences in physical activity engagement between differing severe mental illness diagnoses; people with bipolar disorder engage in more physical activity than people with schizophrenia or major depressive disorder. Symptomology and medication side-effects can affect engagement (this will be explored in greater detail later in this chapter). People with severe mental illness are more sedentary than the general population and on average are sedentary between 8–12 hours of the day (Vancampfort, Firth, et al., 2017). High levels of sedentariness may be further complicated by factors associated with the mental health disorders such as social isolation and obesity (Vancampfort, Firth, et al., 2017).

17.1.6.3. Poor Diet

Compared with the general population, people with severe mental illness tend to have diets that are low in nutritional quality and have a higher caloric intake. Medication side effects can increase a person’s desire to eat; desire for energy-dense, low-nutrient foods is particularly increased (Teasdale et al., 2017).

17.1.6.4. Sleep and Mental Illness

As in the general population, sleep is a significant component of maintaining good physical and mental health and represents a growing facet of mental health research (Firth et al., 2020). When sleep is impaired, it can lead to weight gain, increasing a person’s risk of the development of obesity and metabolic abnormalities. For people with severe mental illness, sleep disturbances are a highlighted risk factor that can lead to the development of psychiatric symptoms in addition to the exacerbation of known symptoms. For people with a mental disorder, up to 90% report abnormal sleep behaviour, which can include difficulty initiating sleep or insomnia (Abad et al., 2005). Symptoms of severe mental illness such as paranoia can impact sleep quality (Afonso et al., 2014), and medications can impact sleep duration and as such decrease sleep quality (Correll et al., 2011). Given the prevalence of poor sleep within this population group, providing interventions that promote good sleep practices is paramount. Importantly, regular physical activity is associated with improvements in self-reported sleep quality in people with mental illness (Lederman et al., 2018).

17.1.7. Social Determinants of Health

High rates of early death and cardiometabolic risk are prevalent in people with severe mental illness even once lifestyle risk factors are accounted for (Hamer et al., 2008). This suggests that physical health is influenced by external factors including the provision and availability of health care, socioeconomic status, and geographical location. People with severe mental illness are less likely to have access to and engage in quality health care services compared to the general population. Social determinants of health, which includes employment and financial insecurity, homelessness, poor education, and poverty, increase a person’s risk of developing mental and physical illnesses (Marmot, 2005).

Learning Exercise One

Describe some common symptoms of the main diagnoses of severe mental illness and include how these symptoms may affects a person’s daily functioning.