We talked to Giovanni Martinotti, Professor of Psychiatry at UniCamillus University
There are days when temperatures are so extreme that it seems there is no respite. Muggy weather at such high levels is not only a threat to physical health, but also has profound effects on mental health, especially for people with pre-existing psychological disorders. Numerous studies show a close connection between extreme heat and a wide range of psychological disorders, ranging from increased irritability to aggression, depression and suicidal thoughts.
Moreover, during heatwaves, the quantity and quality of sleep are severely affected, thus playing a significant role in exacerbating problems related to memory, attention and reactivity.
Also, some psychotropic drugs, such as certain categories of antidepressants and antipsychotics, can interfere with the body’s ability to manage temperature self-regulation, thus worsening the discomfort.
Another group of people in danger are those suffering from dementia, who may not be able to recognise or communicate symptoms of excessive heat, resulting in episodes of heat stroke.
To better understand this problem and to try to recognise the warning signs for us and the people around us as early as possible, we interviewed Giovanni Martinotti, Lecturer in Psychiatry at UniCamillus University in Rome.
What are the physical symptoms that can aggravate a pre-existing state of mental discomfort?
‘Physical symptoms, often exacerbated by high temperatures, can often worsen pre-existing mental discomforts, creating a negative cycle that can affect the quality of life. Subjects with anxiety or depression usually experience more physical symptoms. One hypothesis is that these patients experience specific physical symptoms related to the discomfort. Here are some of the physical symptoms that can negatively affect mental health:
- Sleep disorders: insomnia, hypersomnia, sleep continuity and sleep depth can cause irritability and difficulty concentrating. Lack of restful sleep can therefore worsen mental health in the long term.
- Chronic pain: headaches, back pain, arthritis and other painful conditions can reduce a person’s ability to cope with stress and negative emotions. It is important that chronic pain is properly managed to reduce its impact on mental health.
- Fatigue: constant fatigue, especially without an apparent cause, can reduce a person’s ability to cope with stress.
- Respiratory disorders: conditions such as asthma or chronic obstructive pulmonary disease (COPD) can aggravate anxiety and panic attacks, especially when they are severe.
- Nutritional deficiencies: vitamin deficiencies, especially B vitamins, but also of essential minerals such as iron and magnesium are linked with a wide range of mental disorders and aggravate their symptomatic presentation.
- Hormonal imbalances: hypothyroidism, hyperthyroidism, hyperparathyroidism or changes related to the menstrual cycle or menopause can affect mood and emotional stability.
- Gastrointestinal disorders: up to one third of people diagnosed with irritable bowel syndrome (IBS) also suffer from anxiety or depression. In recent years, research has increasingly been focussing on discovering the mutual connection between intestines and brain.
The number of physical symptoms, rather than the specific type of symptom, has been shown to be predictive of psychological distress. It is important, therefore, that physical symptoms are properly managed to also reduce their impact on mental health, especially in extreme heat with hardly tolerable temperatures. Consulting a physician or mental health professional can be helpful in developing an integrated treatment plan.’
Which mental health problems can worsen in summer?
‘High temperatures have significant effects on human health and well-being, especially because of climate change. People with psychological disorders may find it difficult to cope with hot weather, as their adaptation mechanisms, such as seeking cool environments, wearing appropriate clothing and drinking water, may be limited.
Studies have shown that individuals with depression may show a dysfunction in thermoregulation mechanisms, with an increase in body temperature in response to heat. It has been found that dopamine/noradrenaline reuptake inhibitors significantly increase body temperature during exercise. Furthermore, selective serotonin reuptake inhibitors (SSRIs) may alter the perception of thirst, thus increasing the risk of drug-induced hyponatriemia during hot weather. However, a recent study concluded that antidepressants are not associated with an increased risk of death during heat waves.’
What are the usual symptoms of emotional disorders that are worsened by high temperatures?
‘Some of the symptoms that can most frequently be aggravated by intense heat are irritability and agitation, anxiety, depression, fatigue, lethargy, sleep disturbances, aggression, and difficulty concentrating. Indeed, high temperatures can increase aggression, resulting directly in stronger feelings of hostility and indirectly in increased aggressive thoughts. Furthermore, according to recent studies, temperature fluctuations can alter psychological states and cognitive behaviour, predominantly manifested in an increase in negative emotions such as anxiety, depression and sadness, which can potentially lead to psychological complications such as sleep disorders.’
Are there any ‘seasonal’ mental disorders, which, in other words, typically appear in the summer?
‘Yes, definitely. As far as mood disorders are concerned, according to the DSM-5, Seasonal Affective Disorder (SAD) is a subtype of mood disorder, either unipolar or bipolar, that follows a seasonal pattern. Although SAD is most commonly associated with the winter months, there is also a variant that occurs during the summer months. According to DSM5-tr the diagnosis of SAD requires meeting the following criteria:
1) Regular temporal relationship. There must be a regular temporal relationship between the onset of major depressive episodes and a particular time of year (e.g. autumn or winter). Situations in which there is an obvious effect of seasonal psychosocial stressors (e.g. seasonal unemployment) should not be included.
2) Characteristic remission. Complete remission (or the transition from major depression to mania or hypomania) must occur at a specific time of the year (e.g. depression disappears in spring).
3) Two-year pattern. During the last two years, episodes of major depression must have had a seasonal temporal relationship and no non-seasonal episodes of major depression must have occurred during this period.
4) Prevalence of seasonal episodes. Seasonal episodes of major depression must significantly exceed the number of non-seasonal episodes over the individual’s lifetime.
As far as schizophrenia is concerned, several studies conducted in both the Southern and Northern hemispheres consistently show an association between the time of admission or the onset of the first episode of schizophrenia with the short photoperiod (peak in winter), while one study reported a further peak in June.
Regarding anxiety-related disorders, one study investigated whether they could show a seasonal pattern through a retrospective, cross-sectional, observational and descriptive analysis of outpatient psychiatric consultation data in a university hospital, but no statistically significant association was found between them and the summer period. Moreover, there was no significant difference in the seasonal prevalence of consultations.
The seasonal pattern in psychiatric disorders is widely documented and mainly related to changes in circadian rhythms. These rhythms, strongly influenced by light, regulate many body and brain functions. Dissonance between circadian rhythms and seasonal variations in sunlight can increase the risk of mood and behavioural problems as well as worsen symptoms of pre-existing psychiatric disorders.
Humans evolved near the equator, where the light-dark cycle is constant throughout the year. However, during migrations to higher latitudes, they have had to adapt to significant variations in seasonal photoperiods. This genetic adaptation to changes in day length could be related to susceptibility to mood disorders, such as SAD.
Taking into account some considerations of biochemistry, seasonal variations seem to affect several neurotransmitter systems, particularly the serotonergic (5-HT) and dopaminergic (DA) systems. Studies have shown that serotonin levels in the brain vary seasonally, with lower levels in winter, which could explain the increase in depressive symptoms during the winter months. In summer, increased dopamine levels may contribute to manic or hypomanic symptoms in patients suffering from bipolar disorder.
Circadian rhythms are biological rhythms that follow an approximately 24-hour cycle and are mainly regulated by light. The suprachiasmatic nucleus (SCN) in the brain is the main circadian pacemaker and receives input from light, regulating neuronal activities, body temperature and hormonal signals.
Melatonin is the sleep hormone, responsible for maintaining our circadian rhythm and ensuring a quality sleep-wake cycle. Since darkness prompts the brain to produce melatonin and production slows or stops during the day, any changes in the amount of sunlight can alter our circadian rhythm, potentially disrupting sleep. This is especially true during summer, when days are longer, and winter when hours of sunlight are shorter.
Dysfunctions in circadian rhythms are often observed in patients with psychiatric disorders and may contribute to the seasonality of symptoms.’
Are there any categories of people who are more at risk?
‘Yes, of course. Among psychiatric patients, there are particular groups that are more vulnerable for several reasons, such as treatments they are undergoing, socio-economic conditions, employment and other biological factors.
Elderly Patients
Elderly people suffering from psychiatric disorders are among the most vulnerable during heat waves. As we age, our body’s ability to regulate temperature decreases due to changes in the skin, blood circulation and the function of sweat glands. In addition, many elderly people take medications that may reduce sweating and then increase the risk of hyperthermia or conversely increase sweating (SSRIs). Moreover, comorbidities such as heart, lung and kidney diseases, which are common among the elderly, further increase this risk. A lack of care, social isolation and limited access to cool, air-conditioned spaces contribute to increased vulnerability.
Adolescents
Adolescents, especially those with mood disorders such as bipolar disorder, may be adversely affected by high temperatures that can exacerbate manic and hypomanic symptoms.
In addition, they have less developed thermoregulatory mechanisms than adults. This means that their bodies are less efficient at dissipating heat through sweating and some other physiological responses are reduced. They also tend to be more physically active, often spending a lot of time outdoors during the summer months, which adds to the risk of heat stroke.
Patients suffering from Substance Use Disorder (SUD)
Stimulant drugs, such as cocaine and methamphetamines, increase the activity of the sympathetic nervous system, which leads to higher body temperature, which, in turn, makes users more vulnerable to heat stroke, as the body already operates at high temperature levels even without the external influence of heat. Stimulant drugs can also interfere with the body’s ability to regulate temperature through sweating. Methamphetamines, for example, can reduce sweating, making it difficult for the body to dissipate excess heat, whereas cocaine can cause vasoconstriction, which reduces blood flow to the skin, preventing heat dissipation through the skin.
Outdoor professionals and workers
People who work outdoors, such as farmers, bricklayers and construction workers, are at greater risk of the negative effects of heat. These individuals are exposed to high temperatures for long periods, increasing the risk of dehydration and heat stroke. Workers with psychiatric disorders, taking medication that interferes with body temperature regulation, may further increase the risk of heat-related complications.
People with socio-economically disadvantaged conditions
Psychiatric patients living in poverty are particularly vulnerable during heat waves. Lack of access to air-conditioned spaces, difficulty affording air conditioning or fans, and social isolation increase the risk of adverse effects of heat. In addition, these people may have limited access to prompt medical care, increasing the risk of serious complications.’
Are there psychiatric medications that can have worse side effects in hot weather?
‘Yes, unfortunately, in all major classes of psychiatric medications there are some whose side-effects may be unfavourable to the patient during the summer heat. Although many of these side effects can be serious, it is important to note that they are relatively rare and that their negative effect often improves over time with continued therapy. However, it is essential that patients are aware of the risks and discuss possible dose adjustments or preventive measures with their GP, such as increasing fluid intake and avoiding outdoor activities during the hottest hours of the day.
Many antipsychotics are known to cause sedation and orthostatic hypotension, both of which can be problematic in extreme heat. Sedation reduces alertness and the ability to perceive heatstroke symptoms, while orthostatic hypotension can lead to sudden fainting, especially when a person stands up quickly. Some second-generation antipsychotics, such as olanzapine and clozapine, inducing weight gain and hyperglycaemia, may also aggravate metabolic problems under heat stress, while clozapine and risperidone may induce constipation and worsen dehydration.
Also among antidepressants are medicines such as tricyclics that, in addition to causing sedation and orthostatic hypotension, can frequently induce xerostomia and constipation, which may worsen dehydration. In addition to tricyclics we can mention SSRIs, which cause sweating and similarly xerostomia.
In patients taking benzodiazepines—exceptional medicines to be used on an as-needed basis in anxiety conditions—the side effects observed include hypotension, fatigue and muscle weakness, making them clearly more vulnerable in a hyperthermic condition.
Among mood stabilisers, there is an even broader and more subspecific range of side effects, with some problematic conditions in the heat of summer. Lithium, for instance, the golden standard in the treatment of bipolar disorder, is known to induce polyuria, which obviously leads to dehydration. Moreover, long-term induced hypothyroidism, if left untreated, can seriously interfere with thermoregulation.
Valproate, another mood stabiliser, induces weight gain and gastrointestinal changes, which would always worsen dehydration. Finally, topiramate can induce hypohidrosis (reduced sweating) by interfering with the body’s ability to dissipate heat.’
Are there any tips for preventing and/or coping with the flare-up of symptoms in summer?
‘Of course. Here are some tips for preventing and dealing with these flare-ups:
- Maintain adequate hydration:
It is essential to drink plenty of water throughout the day, even if you are not thirsty. Avoid alcoholic and caffeinated drinks, which can contribute to dehydration. Constant hydration helps maintain a stable body temperature and prevent dehydration. - Avoid being exposed to the sun during the hottest hours:
Minimize sun exposure between 10.30am and 2pm, when the sun’s rays are most intense. If you have to go outside, try to be in the shade and take frequent breaks in cool, ventilated places. - Dress appropriately:
Wear light-coloured, loose-fitting clothes that enable good air circulation. Use a wide-brimmed hat and sunglasses to protect your face and eyes from the sun’s rays. Apply broad-spectrum SPF sunscreen. - Monitor health conditions:
Monitor blood pressure, heart rate and body temperature regularly. Be aware of initial symptoms of heat-related discomfort, such as nausea, dizziness and muscle cramping, and intervene promptly to cool down and rehydrate. - Plan outdoor activities:
Plan physical activities during cooler hours of the day, such as early in the morning or late in the evening. If possible, prefer indoor exercise in an air-conditioned environment. - Use air-conditioned facilities:
During heat waves, spend time in air-conditioned places such as shopping centres, libraries or community cooling centres. Even short periods spent in a cool environment can help keep body temperature down. - Pay attention to medication:
Some medications may increase heat sensitivity or affect the body’s ability to regulate temperature. It is important to discuss any dosage adjustments or changes in prescriptions with your GP during the summer months. Store medicines in a cool place to avoid degradation. - Be aware of warning signs:
Recognise symptoms of severe heat-related discomfort, such as heat exhaustion and heat stroke. In case of warning signs such as confusion, hot and dry skin, or loss of consciousness, seek immediate medical attention.’
- Maintain adequate hydration:
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