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The Problem
Although relatively few people die from dehydration specifically, a lot of people suffer unnecessarily from a low liquid intake that can impair their general performance and leave them feeling unwell.
Abuse of some diuretic substances can significantly increase the risk of dehydration due to their effect on the body’s hydration system. The associated behaviours and lifestyle traits that often accompany substance misuse increase the danger of physical or cognitive damage. Some of us may remember waking up with a raging thirst after a night of heavy partying – that’s dehydration. Here are some common physical and behavioural changes that can happen when substances that are diuretics are abused and cause dehydration:
- Physiological – many substances, such as alcohol, caffeine, nicotine and certain club drugs, have diuretic properties, meaning they increase urine production and promote fluid loss from the body. Additional stress is placed on the kidneys, compromising their ability to regulate fluid balance and electrolyte levels in the body. This can result in an increased risk of dehydration.
- Decreased Thirst Sensation – substance misuse can impair the body’s natural mechanisms for regulating thirst, leading to decreased sensitivity to hydration needs. As a result, people may not feel the urge to drink water although needing to, exacerbating the risk of dehydration.
- Lifestyle Factors – unhealthy lifestyle choices, including poor nutrition, neglecting self-care, and engaging in risky behaviours are commonly associated with substance misuse. Irresponsibility and lack of attention to hydration lead to an increased likelihood of problems.
- Impaired Decision-Making – substance misuse can impair cognitive functions, including decision-making abilities leading people to prioritise obtaining their drug of choice over simple bodily needs such as food and hydration.
How Does Dehydration Affect the Brain?
Dehydration can have significant effects on brain function which can contribute to cognitive impairment. The brain relies on proper hydration to maintain optimal functioning, and when it receives insufficient liquids, several key mechanisms and processes can be negatively impacted in a number of ways:
- Reduced Blood Flow: reduced fluid intake can decrease blood volume and slow circulation throughout the body, including the brain. As a result, the brain receives less oxygen and nutrients, which are essential for its proper functioning. This can impair cognitive processes and lead to difficulties in attention, concentration, and memory.
- Impaired Neurotransmitter Function: dehydration which involves the loss of electrolytes, such as sodium, potassium and calcium, can affect the balance and release of neurotransmitters in the brain, which are chemical messengers that facilitate communication between neurons. These play a vital role in cognitive processes such as learning, memory, and mood regulation.
- Impact on Brain Structure: prolonged or severe dehydration can lead to the shrinking of brain tissue. This can affect the integrity and structure of brain cells, potentially leading to cognitive deficits. This structural damage may take time to recover even after rehydration.
- Altered Brain Activity: dehydration can result in changes in brain wave patterns and electrical activity. Electroencephalogram (EEG) studies have shown that dehydrated individuals may exhibit altered brain wave patterns associated with decreased alertness, impaired attention, and slower cognitive processing.
- Impaired Temperature Regulation: proper fluid intake is essential for maintaining normal body temperature. Dehydration can disrupt the body’s thermoregulatory mechanisms, leading to an increase in core body temperature. Elevated body temperature can directly impact brain function and contribute to cognitive impairment, confusion, and fatigue.
It’s important to note that the severity of cognitive impairment due to dehydration can vary depending on the degree and duration of dehydration, as well as individual factors. Rehydrating adequately and promptly can help restore proper brain function and alleviate the damage caused by dehydration.
Certain substances – alcohol, nicotine and MDMA (ecstasy) for example – have a diuretic effect on the body leading to dehydration which can have harmful consequences. This is especially dangerous since the user may be unaware of what is happening.
What Are the Long-term Consequences of Dehydration?
Substance misuse-related dehydration can have severe consequences for both physical and mental health although these may vary depending on the substances involved, the duration and severity of abuse, and the individual’s circumstances – age and general health, for example. Here are some commonly found consequences:
- Organ Damage: significant strain can be put on the body’s metabolic and cardiovascular system increasing the risk of liver disease, kidney damage, and heart problems.
- Cognitive Decline: chronic dehydration resulting from substance misuse can contribute to long-term cognitive impairment. The brain relies on adequate hydration for optimal function, and prolonged dehydration can lead to difficulties in memory, attention, decision-making, and problem-solving. These cognitive deficits may persist even after the substance misuse has stopped.
- Mental Health Disorders: insufficient liquid intake can contribute to the worsening of mental health disorders producing symptoms of depression, anxiety, and other psychiatric disorders. Substance misuse itself is often linked to mental health problems and dehydration can further exacerbate these.
- Weakened Immune System: substance misuse combined with dehydration can weaken the immune system, making people more susceptible to infections, illnesses, and slower healing from injuries.
- Gastrointestinal Problems: chronic gastrointestinal issues such as constipation, gastric ulcers, and gastrointestinal bleeding can occur when liquid intake is limited significantly. The digestive system may be already irritated by substance misuse and dehydration intensifies the problems. This can cause long-lasting damage to the gastrointestinal tract.
- Nutritional Deficiencies: substance misuse often disrupts eating patterns and can lead to poor nutrition. Combined with dehydration, this can impact overall health and contribute over time to a range of physical and cognitive problems.
- Increased Risk of Accidents and Injuries: dehydration impairs cognitive function, coordination, and reaction time, increasing the risk of accidents and injuries. Substance misuse further compounds this risk.
Warning Signs That You May Be Dehydrated
There are many warning signs of dehydration but substance misuse can affect a person’s ability to notice them or to take remedial action. Checking oneself regularly can be a useful part of maintaining general good health. Look for the following signs:
- Thirst: feeling consistently thirsty is an obvious sign of dehydration. It serves as a natural prompt to drink fluids, but the signals can be impaired by certain drugs.
- Dry Mouth and Lips: when dehydrated, the mouth and lips may feel sticky, or parched. Saliva production decreases, leading to discomfort and a dry sensation.
- Dark or Decreased Urine: dehydration causes a decrease in urine output, and the urine may appear darker in colour than usual. Dark yellow or amber-coloured urine is a sign of concentrated urine due to insufficient hydration.
- Fatigue and Weakness: a decrease in energy levels and overall fatigue resulting in tiredness, lethargy and a decline in physical and mental performance.
- Dizziness and Faintness: reduced fluid levels can cause a drop in blood pressure, leading to feelings of light-headedness.
- Headaches and Migraines: lack of proper hydration affects blood flow and brain function, leading to discomfort and repeated headaches.
- Dry Skin and Reduced Elasticity: insufficient fluid intake can affect the skin’s appearance and texture leaving it dry, rough, or lacking elasticity, potentially leading to more ageing and wrinkles. Pinch the skin on your forearm between your finger and thumb – if it is slow to bounce back to its normal shape, you are probably dehydrated.
- Muscle Cramps: electrolyte imbalances, particularly in cases of excessive sweating or physical exertion, can result in cramps, spasms, or feelings of muscle fatigue.
- Rapid Heartbeat: as the body tries to compensate for decreased blood volume this shows as a faster or irregular heartbeat.
- Confusion and Irritability: in severe cases of dehydration, signs of confusion, irritability, or difficulty concentrating can appear and cognitive functions generally deteriorate.
It’s important to note that the severity and combination of symptoms can vary based on the individual and the extent of dehydration. If you suspect dehydration or experience any of these warning signs, it is vital to rehydrate by drinking fluids and seek medical attention if symptoms persist or worsen.

Hydration Practices to Counteract Substance Misuse-Related Dehydration
Consumption of some substances can lead to dehydration, which in turn can have detrimental effects on cognitive function. However, there are some hydration routines that you can adopt to counteract potential harm. Here are some key strategies:
- Limit Substance Consumption: this is an obvious first step in preventing dehydration. Moderation is key, as excessive consumption of some substances, especially alcohol, can significantly increase fluid loss.
- Increase Fluid Intake when Using: to counteract the dehydrating effects of substances, it is important to increase fluid intake. Drinking water before, during, and after consuming drugs can help maintain hydration levels. It is also beneficial to choose non-alcoholic, hydrating beverages alongside or in between alcoholic drinks.
- Hydrate before Bedtime: alcohol and drugs can disrupt sleep patterns and further dehydrate the body during the night. To mitigate this, make sure to drink a glass of water before going to bed.
- Eat Hydrating Foods: consuming foods with high water content can contribute to overall hydration. Include fruits and vegetables with high water content, such as watermelon, cucumbers, oranges, and strawberries, in your diet. These foods also supply helpful vitamins and minerals for the brain.
- Replenish Electrolytes: electrolyte-rich beverages or foods, such as coconut water or some sports drinks can replenish electrolyte levels and restore the body’s hydration balance. Read the labels carefully to avoid caffeine-rich drinks.
- Be Mindful of Hydration Throughout the Day: adopt healthy hydration habits such as drinking a glass of water every mealtime. Carry a reusable water bottle as a reminder to stay hydrated and make it easily accessible.
- Monitor Signs of Dehydration: It is essential to be aware of the warning signs of dehydration as shown above. If any of these symptoms occur, act by drinking fluids promptly.
- Seek Professional Help if Needed: it is sensible to seek professional help if you are worried. Consulting a healthcare specialist can provide guidance in managing hydration as a basic health need.
Can Dehydration Contribute to Substance Misuse?
Dehydration itself does not directly cause substance misuse which is a highly complex disorder. However, it can indirectly contribute to the vicious cycle of self-defeating behaviour that substance misuse represents in the following ways:
- Impaired Decision-Making: when people are dehydrated, their judgment and impulse control may be compromised, making them more susceptible to engaging in risky behaviours, including substance misuse.
- Seeking Relief: dehydration can cause discomfort, fatigue, and other physical symptoms that people may attempt to alleviate. Some individuals may turn to substances, such as alcohol or drugs, as a means to self-medicate and temporarily relieve their discomfort. Drinking a beer for example, because you feel thirsty will ultimately leave you more dehydrated.
- Impaired Self-Care: lack of proper hydration is an example of neglect of one’s needs that can contribute to the likelihood of engaging in substance misuse as a form of escape or coping mechanism.
- Social Factors: where mood, energy levels, and overall well-being are low as a result of dehydration, this can lead to social isolation, lack of support, and negative influences such as addictive behaviour.
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Raising Awareness of Dehydration
Over two-thirds of the healthy human body is water, according to the NHS. The water we ingest helps the lubrication of the eyes and joints, eliminates waste and toxins, facilitates the digestive system and maintains a healthy skin tone. When we do not drink enough water, we feel unwell and this can lead us into dangerous patterns of behaviour, especially if we take mood-altering substances. Maintaining a positive attitude to good hydration is common sense – it will make us feel think and look better.
At Castle Craig, we recognise the need for all aspects of good bodily health for recovery from addiction. If you would like to know more about our treatment programmes or if you are worried about your own or someone else’s possible addictive behaviour, call us in confidence on 080 271 7500