18. Physical Illness

It shouldn’t come as a shock that your physical and mental health are connected. But you may be surprised just how interconnected they actually are.

If something is wrong in your brain, it makes sense that it could affect your mood and behaviour. Yet, the connections go far deeper than that. If you have some physical illnesses, such as coronary artery disease, you’re far more likely to develop mental health issues such as depression and anxiety. It works the other way too. Untreated mental health issues greatly increase your chances of developing certain physical illnesses. They can also lead to poorer outcomes of physical illness. It’s one of the many reasons why treating mental illness is so important.

Why do we say addressing physical illness is a mental health treatment? Quite simply, illness may contribute to or cause your mental health symptoms. Dealing with physical health problems may reduce or eliminate mental health problems.

Needless to say, this chapter may not be the gentlest read for hypochondriacs. It’s also not great if you avoid doctors in case they “find something.” Yet, it’s still tame compared with an internet search on any symptom you care to mention. We are not suggesting you test for any physical illness that could possibly cause a symptom. Based on your history, physical and mental health symptoms, and your response to treatment, your doctor can judge what to look at further.

Physical Illness Impacts Mental Health

If you’re having new mental health symptoms, could a physical health issue be contributing? It’s one of the first things you and your mental health providers should think about. This is particularly true if this is your first experience with mental health symptoms and no obvious stressful events have occurred recently.

Assuming that no physical factors are contributing to your symptoms is a lost opportunity at best. At worst it could be dangerous. Treating a physical illness with antidepressants or psychotherapy will likely fail. Dulling your symptoms with benzodiazepines or antipsychotics may help in the short term. However, unless your physical illness gets better on its own, they won’t help you in the long run. Sometimes mental health symptoms are the first signs of a physical illness. Identifying and treating a physical illness early is easier than waiting until other symptoms develop.

If you have long-term, chronic physical health conditions such as diabetes or cardiovascular disease, you’re at higher risk of developing mental illness. This, in turn, can worsen your physical illness. Without prompt attention, a devastating negative feedback loop can develop.

Illnesses With Mental Health Symptoms

Sometimes the first signs of a physical illness are what appear to be purely mental health symptoms. Someone with a brain tumour may first develop changes in mood or energy, hallucinations or other psychosis, or even drastic personality changes. It’s easy to understand why since the physical illness directly affects the brain.

Indirectly, deficiencies in iron or other vitamins and minerals can cause mood swings, decreased energy, and poor memory and concentration. We’ll closely examine these deficiencies in the next chapter. Hormone changes can also cause mental health issues. Illnesses such as diabetes, polycystic ovarian syndrome, Addison’s disease, and some cancers all affect hormones, as do normal fluctuations associated with menstruation, pregnancy, and perimenopause in women.

Treatments

If physical health problems can lead to mental health symptoms, so can many treatments for those physical health problems. All medications and natural supplements have possible side effects, including mental health side effects. One broad study1 found that 37% of participants who reported depression used at least one medication that listed depression as a side effect. Here are just a few examples of such medications:

• Accutane (acne);

• Keppra (anticonvulsant for epilepsy);

• Chantix/Champix (stop smoking);

• Estrogen (menopause, osteoporosis, birth control); and

• Interferon (hepatitis, some cancers).

The following medications often cause anxiety as a side effect:

• Prednisone and other corticosteroids (allergies, asthma, inflammation);

• Albuterol and other bronchodilators (asthma, COPD);

• Zyban/Wellbutrin (stop smoking, depression); and

• Antihistamines (high dose for allergies).

Increased Risk

Chronic physical illness increases the risk of mental health problems over time. The increased risk can be related to biological changes from illness, chronic pain, and treatments for the illness itself. There are many psychosocial issues as well. Physical illness can lead to lifestyle changes or disability, and may affect finances or relationships. It can raise challenging existential questions. You may experience grief and loss over dreams you can’t achieve because of poor health. The increased risk of mental illness is substantial.2 Here are a few examples:

• People with chronic physical conditions have double the risk of experiencing a mood or anxiety disorder versus those without a chronic physical condition.

• People with heart disease are three times more likely to develop depression than people without.

• Concerning respiratory disorders, around 75% of people with severe COPD (chronic obstructive pulmonary disease) have depression or anxiety. Those with asthma have a significantly increased likelihood of anxiety or panic.

People with chronic physical illness who develop a mental illness have worse outcomes. The costs to the health system of their treatment—for their physical illness alone—are much higher. They are less compliant with treatment recommendations and more likely to develop poor habits in areas such as diet, exercise, sleep and substance use, that will affect their physical health.

Impact on Treatment

Physical illness also affects how mental illness is treated, even if the two are entirely unrelated. Treatments for mental illness need to factor in any physical illness. Here is why:

• Physical illness can leave you more prone to vitamin and mineral deficiencies. These can prevent antidepressants from working.

• Some medications and supplements for mental illness are not safe to use if you have certain physical illnesses.

• Medications for mental health can worsen physical health symptoms. Many also interact with the medications being used to treat those physical conditions.

Mental Illness Impacts Physical Health

Don’t think that the effects of physical illness on mental health are a one-way street. Mental illness also affects physical illness in very similar ways.

Symptoms

When feeling mentally unwell, you may also have physical symptoms. These are also known as somatic symptoms, i.e., those affecting the body. Some examples are

• pain;

• nausea;

• lack of energy;

• agitation and restlessness;

• changes in appetite and weight; and

• dizziness.

People who are less comfortable with expressing emotion often have more somatic complaints. Members of certain cultures tend to express emotions somatically. Men do this far more often than women.

Treatments

As in all areas of medicine, medications for mental illness often produce physical side effects. They target neurotransmitters in the brain but affect those in the body as well. They can potentially cause nausea, headache, tremor, dizziness, heart rate or blood pressure changes, skin reactions, and many more conditions.

Taken long-term, some of these medications can pose additional risks. These may include obesity, increased cholesterol, changes in heart rhythm, kidney failure, osteoporosis, and other physical changes. Periodic monitoring can detect changes before they become problems.

Increased Risk

Just as having a physical illness increases the likelihood of developing a mental illness, having a mental illness increases the risk of developing a physical illness. Here are a few examples:

• Those who have symptoms of depression have triple the number of chronic physical health conditions compared to the general population.

• Women with depression are 80% more likely to experience heart disease than women without depression.

• People with some mental illnesses have as much as a three times increased risk of a stroke.

• There are established connections between mental illness and increased inflammation, a decreased immune system, and increased digestive distress.

Your Role

We hope you better appreciate the close interconnection between mental and physical illness. It’s one reason we feel so strongly that medical doctors should play a role in your mental health.

You may not follow the medical model or perhaps you favour alternative treatments. However, if you’re not improving, we’d encourage you to expand your perspective. Make sure there’s not a physical health problem contributing. Use your living treatment plan to prevent tunnel vision, consider alternatives, and reevaluate your treatments.

The intersection of physical and mental health is a potential trouble spot in your care. Professionals working on the physical or mental health side of the divide are often unaware of what’s happening on the other side. It’s your responsibility to bridge this gap. If you’re proceeding with therapy, talk to your doctor about whether a physical illness could be having an effect. Make sure they know your full health history, even if you think parts don’t matter. If you have multiple professionals involved in your mental health care, it’s up to you to let each one know what the others are up to.