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A Closer Look at Mental Health in Hot Weather

A Closer Look at Mental Health in Hot Weather

By Eleanor Vincent, EdD, CSAC

summer-heatSummer is here and the days are longer and hotter! People are spending more time outdoors doing seasonal work, pursuing leisure activities, or simply spending time with friends and family. At the same time, it is important for everyone to take precautions against sun and heat-related problems. Individuals with mental illnesses, especially those on certain types of medications, should take even greater precautions because they are at greater risk of experiencing adverse reactions related to sun exposure, such as dehydration.

Dehydration is a big concern during hot weather. Human beings lose body fluids when they drink too little fluids or sweat excessively. Prolonged vomiting and/or diarrhea can also cause dehydration. Common symptoms of dehydration include dry sticky mouth, thirst, few or no tears, headaches, sleepiness or tiredness, dry skin, constipation, unusually dark urine, or less urine than normal (Mayo Clinic, 2011). Severe dehydration can lead to changes to the body’s chemistry and can become life threatening if not treated promptly.

Heat-related Illnesses

Heat related illnesses are also major concerns during the summer months. The most common are heat cramps, heat exhaustion, and heat stroke. Heat cramps can occur in any muscle and are caused by not stretching adequately before a strenuous exercise in hot weather, or when re-hydrating only with unsalted fluids (US Department of Health & Human Services [DHHS], 2011).

Heat exhaustion is caused by exposure to high temperatures, excessive sweating, and inadequate replacement of salt and water (DHHS, 2011). Symptoms include headache, nausea, vomiting, lethargy, irritability, and thirst.

Heat stroke is a medical emergency that involves extremely elevated body temperature (greater than 106 degrees in minutes), lack of sweating, and neurological dysfunction. In short, it occurs when the body loses its ability to control its temperature and cannot displace heat. Heat stroke can result in severe damage to major organs such as the heart and liver, as well as seizures which can be life-threatening and require immediate medical attention. Additionally, certain medications that individuals with mental illnesses take can decrease the body's ability to cool itself, and present a greater health risk during extreme temperatures.

Medications and Hot Weather

Medications used in the treatment of mental illnesses, such as antipsychotic medications, antihistamines, antiparkinsonians ("side effect meds"), and antidepressants, may increase the risk for dehydration and other physical problems. Frequently these medications are used together, further increasing the potential for dehydration. Also, these medications have similar side effects, which can increase if the individual taking them does not drink enough fluids. The side effects of these prescribed medications can often look like symptoms of dehydration, for example, dry mouth, nausea, anxiety, lethargy or drowsiness. It is therefore very important to consult a physician regarding any unusual symptoms or discomfort, especially during the summer months.

Some medications are more likely to increase the risk of heatstroke and other heat-related illnesses because they affect how the body responds to heat and how it remains hydrated. Some examples include medications that narrow blood vessels, regulate blood pressure by blocking adrenaline (vasoconstrictors) or getting rid of sodium and water (diuretics), or reduce psychiatric symptoms (antidepressants/antipsychotics). Other drugs, such as those used to treat attention-deficit hyperactivity disorder (ADHD), and illegal substances such as amphetamines and cocaine, also increase the risk of heatstroke (Mayo Clinic, 2011a). Additionally, lithium, a medication used to treat bipolar disorder, has a very narrow margin between useful (therapeutic) and harmful (toxic) levels. Dehydration can cause therapeutic lithium levels in the body to rise and become toxic, leading to a medical emergency that requires immediate medical attention.

There are many types of prescription and over-the-counter medications that can cause phototoxicity, for example, Doxepin, Chlorpromazine, HCTZ, and Lovastatin. This extreme sensitivity of the skin to sunlight can occur when the skin is exposed to the sun after certain medications are injected, taken orally, or applied to the skin (WebMD, 2012). It is therefore important to wear sunblock and protective clothing when in the sun. It is equally important to remember not to use any medications without medical advice in order to avoid potentially dangerous drug interactions.

People at High Risk of Heat-related Illnesses

Schizophrenia, a thought disorder, can cause someone to not accurately interpret the environment and at times the person with schizophrenia has difficulty identifying appropriate dress for the season. A cuddly, warm winter jacket might give a sense of comfort and security, but worn in the middle of summer, it can also lead to excessive fluid loss from sweating. Also at risk are individuals living alone because they may not seek treatment and their symptoms may go unnoticed. Additionally, the very young and the very old are more susceptible to heat-related illnesses because the body is less able to manage changes in body temperature. This is because the central nervous system is underdeveloped in the very young and it is beginning to deteriorate in persons over 65 (Mayo Clinic, 2011a).

Tips for Staying Safe in Hot Weather

The best way to safely enjoy summer outdoors is prevention. Avoid prolonged exposure to the sun; drink plenty of fluids (at least 8 to 10 tall glasses daily); avoid caffeine, sugar and alcoholic beverages as they promote fluid loss; do not engage in strenuous exercise during warm conditions; wear light-colored summer clothing; and stay in an air-conditioned environment as much as possible. At the same time, do not shrug off unusual signs and symptoms. Consult with a physician if they occur and have a fun, safe summer!



US Department of Health and Human Services.  Chemical Hazards Emergency Management.  (2011).  Heat-related illness.  Available at

Mayo Clinic. (2011). Dehydration: Symptoms.  Available at

Mayo Clinic. (2011a). Heat Stroke: Risk Factors.  Available at

WebMD. (2012).  Sun-sensitizing drugs.  Available at


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