Psychological Issues and Diving

There is little research on the relationship between mental health conditions and scuba diving. While there are some obvious reasons people shouldn’t dive — i.e., they are out of touch with reality, severely depressed and suicidal or paranoid with delusions and hallucinations — many people with everyday anxieties, fears and neuroses can dive safely. However, scant research has been done on the correlation between common conditions such as depression, bipolar disorder, anxiety, phobias, panic disorders, narcolepsy and schizophrenia and increased risks associated with scuba diving.

In addition to the risks associated with the condition itself, one must consider the possible hazards of any medications taken to treat it — singly or, even more dangerously, in combination. There are no scientific studies that can confirm the relative safety or danger of taking any given medication in the context of diving.

In terms of danger to divers, medications usually play a secondary role to the condition for which the medication is prescribed. Drugs that carry warnings indicating they are dangerous for use while driving or when operating hazardous equipment should also be considered risky for divers; if they’re dangerous for drivers, they’re risky for divers. The interaction between the physiological effects of diving and the pharmacological effects of medications is usually an educated, yet empirically unproven, assumption. Each situation requires individual evaluation, and no general rule applies to all. Another unknown is the additive effect of nitrogen narcosis on the actual effects of the medication.

Finally, divers have different chemistries and personalities; because of the effects of various gases under pressure, each diver responds differently to abnormal physiological states and changes in their environment. Diving conditions such as decompression illness (DCI), inert gas narcosis, carbon dioxide toxicity, oxygen toxicity, high-pressure nervous syndrome and deep-water blackout all can cause reactions that are similar to a psychoneurotic reaction or an abnormal condition of the brain.

Before advising for or against diving, the certifying physician must know all the possibilities and variations in each case of a diver with psychological issues. Information below also includes the impacts of substance abuse and the implications in diving.

Affective Disorders

About Depression and Manic Depression (Bipolar Disorder)

Depression and manic depression, two major types of depressive illnesses, are known as affective disorders, or mood disorders, because they primarily affect a person’s mood. Different terms, respectively, for affective disorders include unipolar and bipolar disorders.

Depression is a persistent condition that can interfere with a person’s ability to sleep, eat and hold a job and can last for weeks or months at a time. A depressed person almost always feels sad. It becomes difficult to feel any pleasure in life and the person can even become suicidal. Other symptoms include feelings of hopelessness and guilt, loss of interest in normal activities, reduced sex drive, changes in eating habits, insomnia, restlessness and poor concentration.

In this section, we will predominately discuss major depressive disorder and manic depression, encompassing symptoms of depression and mania, with wide mood swings, from deep sadness to the other extreme of elation, often losing touch with reality. Each year, a large number of American adults — the figure varying from 10 million to 19 million according to the source — suffer from an affective disorder.

If you’ve never experienced depression, chances are that at some point in your life, you will. Women are twice as likely as men to experience major depression, while manic depression occurs equally among men and women.

Where do these illnesses come from? Genetic, biochemical and environmental factors each can play a role in the onset and progression of such illnesses. Research shows that some people may have a genetic predisposition to affective disorders. We all can experience occasional emotional highs and lows, but depressive disorders are characterized by extremes in intensity and duration.

Distressing life events can also trigger reactive depression. Losses and repeated disillusionment, from death to disappointment in love, can cause people to feel depressed, especially if they have not developed effective coping skills. If these symptoms persist for more than two weeks, with a leveling or increasing in intensity, this reactive depression may actually have evolved into a clinical depression.

Whatever the cause, the presence of depressive or manic-depressive illness indicates an imbalance in the brain chemicals known as neurotransmitters. This means the brain’s electrical mood-regulating system is not operating as it should.

An episode of depression can usually be treated successfully with psychotherapy or antidepressant medication, or a combination of the two. The choice depends on the exact nature of the illness. With treatment, up to 80 percent of people with depression show improvement, usually in a matter of weeks, according to the National Institute of Mental Health (NIMH).

Of all psychiatric illnesses, affective disorders respond well to treatment. If given proper care, approximately 80 percent of patients with major depression demonstrate significant improvement and lead productive lives, according to the NIMH. Although the rate of successful treatment success is not as high for manic depression, a substantial number experience a return to a higher quality of life.


Depression and bipolar disorders can be treated and maintained through a combination of therapies and medications. However, as with many other medications, medications used to treat affective disorders could have side effects that may be adverse to diving. Work with your physician to determine treatment options and how potential treatments could impact diving.

Implications in Diving

Any condition that clouds a diver’s ability to make decisions underwater poses dangers; diving under such conditions should not be allowed. In addition, we rarely have knowledge about drug changes resulting from the physiological effects of diving. Since such mood-altering drugs used to treat depression are clearly potent, people should use caution when they dive, paying particular attention to the warnings about use.

If symptoms of depression persist for longer than two weeks (see sidebar for a listing of the most commons signs), divers experiencing four or more of the symptoms of either depression, manic-depression or symptoms of both should seek professional help and stop diving until the problem is managed.

Divemasters and instructors should learn to recognize any changes in their divers’ appearances, reactions and personalities and be quick to note any of the above signs and symptoms. Medical professionals should be alert to the dangers of diving for individuals who have these conditions or who take medications that might alter consciousness or affect a diver’s ability to make decisions underwater.

Should a person with depression be certified as “fit to dive?” The merits of each case should be considered, including the type of drugs required, the response to medication and the length of time free of depressive or manic incidents. Most, particularly those divers who have responded well to medications over a long term, probably could receive clearance to dive.

We should also consider the following factors: decision-making ability, responsibility for other divers, and drug-induced side effects that could limit a diver’s ability to gear up and move in the water.

In all cases, prospective divers should be mindful of the safety of buddies, dive instructors, divemasters and other individuals affected by a diving incident. Prospective divers should provide full disclosure of their conditions and medications to the dive instructor and certifying agency.

Anxiety and Phobias

About Anxiety

Anxiety is a normal human emotion we all experience when we face threatening or difficult situations. Associated with the secretion of catecholamines (adrenalin), fear or anxiety can help us avoid dangerous situations or get out of them. It can make us alert and it can spur us to deal with a threat or other problem rather than simply avoiding it (i.e., the “fight or flight” reaction). However, if feelings of foreboding become too strong or last too long, they can hold us back from many normal activities.

In abnormal situations, anxiety is manifested by apprehension and dread, though it cannot be attached to a clearly identifiable stimulus. Anxiety can be accompanied by worried feelings, tiredness, tension, restlessness, loss of concentration, irritability and insomnia. The physical effects of anxiety can range from irregular heartbeat, sweating, muscle tension and pain, heavy, rapid breathing, dizziness, faintness, indigestion and diarrhea, and they’re produced by the effects of increased adrenalin.

People who are experiencing extreme anxiety can often mistake these signs and symptoms for evidence of serious physical illness, and worry about this can aggravate the symptoms.

A more intense form of anxiety is panic, a sudden, unexpected but powerful surge of fear. Panic can cause a wholesale flight from the immediate situation, a reaction that is especially dangerous for scuba divers. A diver who experiences panic at depth is subject to near-drowning, lung overexpansion injuries and death.

In susceptible people a heightened awareness of potential but definite dangers, complicated by a normal anxiety of being underwater, can cause a phobic anxiety state. The diver may then develop an actual fear of descending into the water. Some divers experience this while learning to dive, but other stronger motivating factors — finishing the class, spousal, parental or peer approval, an unwillingness to appear fearful to anyone else — can temporarily override their fears.

An overreactive anxiety state usually occurs in response to a mishap, such as a dive mask flooding with water. This may cause the diver to panic unnecessarily and behave irrationally. Often, this results in emergency ascents with the attendant dangers, frantic grabs for air supplies and lack of concern for the safety of others. This reaction is seen more often in those divers who have an above-normal tendency toward anxiety.

About Phobias

A phobia is an objectively unfounded fear, an anxiety about particular situations or things that are not dangerous and which most people do not find troublesome. People with phobias have the intense signs of anxiety — e.g., irregular heartbeat, sweating, dizziness, etc.

Phobias arise only from time to time, however, in particularly frightening situations. At other times, those who experience phobias don’t feel anxious. If you have a phobia of dogs, you’ll feel OK if there are no dogs around; if you are scared of heights, you’re OK at ground level; and if you can’t face social situations, you will feel calm when there are no other persons around.

A phobia will lead sufferers to avoid situations they know will provoke anxiety, but this will actually worsen the phobia as time goes on. It can also mean that the phobic person’s life becomes increasingly dominated by the precautions taken to avoid the situation feared. Phobic individuals usually know that no real danger exists; they may note that they feel silly about their fears, but, still, they cannot control them. Notably, a phobia is more likely to fade away if it began after a distressing or traumatic event.

About one in every 10 persons will have troublesome anxiety or phobia at some point in life. However, most will never ask for treatment. Some divers have true claustrophobia, preventing their immersion into water or their entry into a recompression chamber. This syndrome may surface only during certain times of stress and diminished visibility, such as in murky water, during night diving or during prolonged diving.

Through these treatments, phobia sufferers receive direct exposure to the fear until the anxiety subsides. One can imagine such direct exposure or can actually confront the phobia’s trigger, the latter a dangerous method of treatment in the underwater setting.

About Panic Disorders

Recent studies suggest that episodes of panic or near-panic may explain many recreational diving accidents and the cause of some diving fatalities. Evidence also shows that individuals who have a high level of underlying anxiety are more likely to have greater responses when exposed to stresses, and, hence, this sub-group of the diving population will experience an increased level of risk. In a recent national survey, more than half of divers reported experiencing at least one panic or near-panic episode.

Panic attacks are often spurred by something that a non-diver would deem serious — entanglement, an equipment malfunction or being startled by some unexpected sea creature. These panic attacks can lead to irrational behavior. If divers and instructors knew more about the phenomenon, perhaps they could screen divers who might be susceptible to life-threatening panic attacks.

Panic attacks are not restricted to beginning divers; experienced scuba divers with hundreds of logged dives sometimes experience panic for no apparent reason. In such cases, it is believed that panic occurs because divers lose sight of familiar objects, become disoriented and experience sensory deprivation. However, among inexperienced divers, panic generally results from a specific reason, such as a loss of air or an encounter with a shark.

Panic can occur when divers reacts quickly but irrationally: their attention narrows, and they lose the ability to sort out options. If, for example, a problem develops with the regulator, the restricted air flow could prompt a panicked diver to ascend rapidly enough to cause an often-fatal arterial gas embolism (bubble) in the bloodstream. This would be considered a panic response if the diver had other safe options, such as access to a pony bottle (an emergency air supply) or was diving with others who could share their air supply, allowing a gradual ascent.

Some diving activities inevitably lead to anxiety: the stresses of equipment malfunctions, dangerous marine life (e.g., sharks), loss of orientation during cave dives, under-ice or wreck penetration dives, and other stress-laden situations. Diving with faulty or inappropriate equipment or performing high-risk dives has a greater potential to cause panic episodes; with appropriate training and cautionary actions, however, we can prevent or minimize these problems.

Implications in Diving

In determining whether a person with anxiety, phobias and panic attacks should be certified as fit to dive, each case should be evaluated on its own merits, including types of drugs required (if any), response to medication and the amount of time free of anxiety and phobia.

In all cases, prospective divers should fully disclose their conditions and medications to the dive instructor and certifying agency. They should bear in mind the safety of their potential dive buddies, dive instructors, divemasters and other individuals who are affected by diving incidents.

However, as with many other medications, medications used to treat affective disorders could have side effects that may be adverse to diving. Work with your physician to determine treatment options and how potential treatments could impact diving.


About Narcolepsy

A chronic disorder affecting the part of the brain where regulation of sleep and wakefulness take place, narcolepsy can be viewed as an intrusion by dreaming sleep (REM, or rapid eye movement) into the waking state.

Should people with narcolepsy become certified for scuba diving? No scientific studies exist on the subject — all that is written is pure supposition, based on knowledge of the condition and knowledge of what can happen to the diver with decreased awareness or consciousness.

Some individuals, no matter how much they sleep, continue to experience an irresistible need to sleep — these persons are narcoleptics. People with narcolepsy can fall asleep while working, talking or driving a car. These “sleep attacks” can last from 30 seconds to more than 30 minutes. They may also experience periods of cataplexy, or loss of muscle tone, which ranges from a slight buckling at the knees to a complete, “rag doll” limpness throughout the body.

In the general population, narcolepsy happens to one in every 2,000 people. It can occur at any time throughout life, but it will most likely begin during the teen years. Although narcolepsy has been found to be hereditary, some environmental factors contribute. Narcolepsy is a disabling and underdiagnosed illness: for sufferers, the effects can be devastating.

Studies have shown that even treated patients are often significantly psychosocially impaired in the areas of work, leisure and interpersonal relations, and they are more prone to accidents. These effects are even more severe than the well-documented deleterious effects of epilepsy when similar criteria are used for comparison.

Symptoms include excessive sleepiness, a temporary decrease or loss of muscle control (sometimes associated with getting excited), vivid dreamlike images when drifting off to sleep and waking up unable to move or talk for a period of time.

Implications in Diving

The merits of each case, the drugs required, the response to medication and the length of time free of narcolepsy should determine each diver’s fitness. How each diver copes with excitement, emotions and stressful situations are key considerations.

Any prospective diver should fully disclose this condition and any medications to the dive instructor and certifying agency. In addition, any prospective diver with narcolepsy should be mindful of the safety of buddies, dive instructors, divemasters and other individuals who can be affected by diving incidents. Divers with this condition who choose to dive might consider using a full-face mask to decrease the risk of drowning in case of unconsciousness during a dive.


About Schizophrenia

Schizophrenia is a serious mental illness that affects one person in 100. It usually develops in the late teens or early twenties, though it can start in middle age or even much later in life. The earlier it begins, the more potential it has to damage the personality and the ability to lead a normal life. Although schizophrenia is treatable, relapses are common, and it may never resolve entirely. Sufferers typically have difficulty working and studying, relating to other people and leading independent lives. It causes great distress in families.

With this disorder, thoughts, feelings and actions are somewhat disconnected from each other. This may be easier to illustrate by describing the symptoms: Positive symptoms are abnormal experiences; negative symptoms are more an absence of normal behavior; and disorganized symptoms indicate the extent of disorganization of the patient’s thought processes and vocalizations.

Positive Symptoms

We normally feel that we are in control of our thoughts and actions, but schizophrenia interferes with this feeling of being “the captain of the ship.” It may feel as though thoughts are being put into the mind or removed by some outside, uncontrollable force. At worst, the whole personality seems to be under the influence of an outside force. This is a terrifying experience, which the person tries to explain according to education and upbringing.

Hallucination is the experience of hearing, smelling, feeling or seeing something that is not there. Voices are the most common hallucination, and they often appear so real that the hearer is convinced that they come from the outside – as if from loudspeakers or a spirit world. These voices are distressing, as they talk about the person as well as to the person.

Delusions, false and usually unusual beliefs, cannot be explained by the believer’s culture or changed by argument. These ideas may be fantastic, as in “I’m God’s messenger!” or apparently reasonable — “Everyone at work is against me.” Persecutory delusions are especially distressing for the family if members are seen as the persecutors. Delusions may come out of the blue or may start as an explanation for hallucinations or the sensation of being “taken over.”

Negative Symptoms

These affect interest, energy, emotional life and everyday activities. Those individuals with negative symptoms generally avoid meeting people, say little or nothing and may appear emotionally blank.

Disorganized Symptoms

Schizophrenia often interferes with a person?s train of thought; it often becomes difficult to understand them. Those with schizophrenia will shout back at their voices or will comply with the instructions of the voices, often hurting themselves or others.

Implications in Diving

Merits of each case, the type of drugs required, the response to medication, and the length of time free of the disorder should determine whether a person with schizophrenia should be certified as fit to dive. Most probably should not consider diving.

However, some individuals who have responded well to medications over a long term may be considered for diving. Authorities should consider how one’s decision-making ability, responsibility to other divers and any drug-induced side effects might limit a diver’s ability to gear up and move in the water. Prospective divers should fully disclose such information to the dive instructor and certifying agency. Individuals responsible for divers should be alert to divers with inappropriate responses or activity, paranoid behavior or unusual ideas and be quick to ask about the possibility of schizophrenia.

Substance Abuse

About Marijuana Use

Marijuana use can cause differing effects:

  • The more marijuana is used, the shorter its effects last.
  • Tolerance to the psychoactive effects develops with continued use.
  • Psychological and mild physical dependence gradually occurs with regular use.

Withdrawal symptoms include:

  • Restlessness, insomnia, nausea, irritability, loss of appetite, sweating.
  • Risk of adverse reactions is greater for persons who have had schizophrenia or other psychotic disorder, depression, dysthymia (mood disorder), and bipolar disorder (manic depression).
  • Tar content of marijuana is significantly greater than cigarettes, with more carcinogens (substances producing or inciting cancer).

Potentially harmful effects to divers include:

  • Accidents and deaths caused by distortions in perception of time, body image and distance.
  • Impairment of recent memory, confusion, decreased concentration.
  • Decreased muscle strength and balance.
  • Decreased blood flow in brain.
  • Impaired ability to perform complex motor tasks.
  • Poor memory.
  • Amotivational syndrome.
  • Depression, especially in new users.
  • 50 percent of users will have a “bad trip,” a severe panic reaction with fear of dying or losing one’s mind.
  • Fast heart rate and lower exercise tolerance.
  • Dry mouth and throat.

High doses may cause:

  • Hallucinations.
  • Depersonalization.
  • Paranoia.
  • Agitation.
  • Extreme panic.

Chronic use may cause:

  • Bronchitis, sinusitis, pharyngitis (inflammation of the mucous membrane and underlying parts of the pharynx), chronic cough, emphysema, lung cancer.
  • Poor immune system functioning; severe marine infections.
  • Poor motivation, depressed mental functioning.

About Blood Alcohol Concentration (BAC)

Research has shown that one’s ability to process information diminishes, particularly in tasks that require undivided attention for many hours after the blood alcohol level has reached 0.015 percent. This means that the risk for injury of a hung over diver increases significantly, particularly if high BAC levels were reached during the drinking episode.

The American Medical Association (AMA) upper limit of the BAC for driving a vehicle in the United States is 0.05 percent.

Implications in Diving

Usage of marijuana could create possible adverse side effects for divers, including:

  • Dizziness: This is a fairly common side effect, which often disappears with continued use.
  • Less common side effects may include: headache, constipation, nervousness, fatigue, insomnia, limb or abdominal pain, and weight loss.

Alcohol use also causes impairment. The following behavioral components required for safe diving diminish when alcohol is on board or has been on board in the previous 24 hours:

  • Reaction time
  • Visual tracking performance
  • Concentrated attention
  • Ability to process information in divided attention tasks
  • Perception (judgment)
  • The execution of psychomotor tasks.

The individual who has alcohol on board may not feel impaired or even appear impaired to the observer, but that person definitely is impaired. This can persist for extended periods. The use of alcohol, even in moderate doses, clearly carries a self-destructive aspect of behavior and leads to higher probabilities for serious accidents.

Ernest Campbell, M.D., FACS


National Institute of Mental Health, Information Resources and Inquiries Branch, 6001 Executive Boulevard, Room 8184, MSC 9663, Bethesda, MD 20892-9663, Telephone: +1-301-443-4513, FAX: +1-301-443-4279, Depression brochures: +1-800-421-4211, TTY: +1-301-443-8431, FAX4U: +1-301-443-5158, Email: , Website:

National Alliance for the Mentally Ill, Colonial Place Three, 2107 Wilson Blvd., Suite 300, Arlington, VA 22201-3042, +1-703-524-7600; 1-800-950-NAMI, Website:

National Depressive and Manic Depressive Association, 730 N. Franklin, Suite 501, Chicago, IL 60601, +1-312- 642-0049; +1-800-826-3632, Website:

National Foundation for Depressive Illness, Inc., P.O. Box 2257, New York, NY 10016, +1-212-268-4260; 1-800-239-1265, Website:

National Mental Health Association, 1021 Prince Street, Alexandria, VA 22314-2971, +1-703 684-7722; +1-800-969-6642, FAX: +1-703-684-5968, TTY: +1-800-433-5959, Website:

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