Depression & Diving: Part II
Making the Call on Recreational Diving

by Doc Vikingo
This article first appeared in DAN's Alert Diver, July/August 2003.

In the March/April 2003 issue, Alert Diver took an in depth look at the
nature, classification and treatment of depression, and briefly touched upon its
implications for diving. In this follow up, we focus in detail on how the
signs and symptoms of the condition, and their medical management, can impact
safe scuba for the recreational diver and his buddy.

About one in 20 Americans show characteristics of a depressive disorder.
And, because some antidepressants are used for other conditions as well, more
than one in 15 takes such a medication.

As research suggests that the prevalence of depression in active divers does
not significantly differ from that found in the general population, it is
critical to understand what this disorder means for affected divers and the
mental health professionals who treat them. During calendar year 2002, DAN
Medical Services received 125-130 inquiries regarding diving with depression, and
about an equal number specifically concerning the drugs used to treat it.

In a nutshell, depression is a disorder of mood. Sufferers complain of or
are described by others as being down, blue, sad or empty, and as having
reduced interest in or capacity to enjoy activities they once found pleasurable.
Other features include disturbed sleep, changes in appetite and weight,
feelings of worthlessness, hopelessness and guilt, thoughts of doing away with
oneself, lack of energy, easy fatigue, loss of libido, restlessness, irritability,
and difficulty in paying attention, concentrating and making decisions. In
addition, depressive episodes can alternate with manic ones. With the latter,
there can be groundless or excessive feelings of well-being and happiness,
racing thoughts, poor judgment, recklessness, and a tendency to be easily
distracted.

Of course not every individual will have all of these, and the severity
ranges from mild to requiring hospitalization. The disorder is treated both by
psychotherapy and medication, and often responds best to the combination.

The decision to dive or not largely takes care of itself at either extreme
of the severity spectrum. However, those cases falling in between can be
vexing, especially when the disorder is to varying degrees controlled by
medication.

Issues related to the disorder itself:

Among common signs and symptoms, indecisiveness and poorly sustained
concentration perhaps rank highest on the list of concerns. Tracking and managing
variables such as one's depth, location, air supply, NDLs and buddy status
requires a high level of vigilance and sound, smooth decision-making. Deep
underwater is not a benign place to suffer lapses in attention and decisional
sharpness.

Divers revel in those seemingly effortless dives where perfect neutral
buoyancy is achieved as we ride a gentle current past expanses of colorful reef.
However, the requirement for vigorous activity is often just around the corner
in the form of a wicked down current or buddy in need of rescue. I would not
like my energy level or resistance to fatigue, or that of my buddy, to be
reduced during scuba, and this can be seen in depression

Things don't always go smoothly while diving, either above or below water.
Boats can arrive late, be crowded, and have dictatorial crew. Once down, the
diver can inadvertently brush up against fire coral, get snagged in fishing
line, or have an inconsiderate diver spoil a special photo opportunity. If
irritability, which is quite common in depression, rears its head at minor
provocation you have a diver who is not in optimal control.

Consideration must also be given to suicidal thought, intent and plan. Up to
9 percent of suicides in regions with easy access to water are due to
drowning, and scuba offers a ready mechanism for death, one that can look to all
the world like an accident. While good statistics are not available for obvious
reasons, it is known that suicide accounts for a number of scuba deaths. It
has been estimated that suicide may be responsible for as much as 17 percent
of the deaths of professional divers in the United Kingdom. And, although not
conclusive, investigations of a number of high profile scuba deaths, such as
those of an ophthalmologist from Wisconsin (in Wisconsin), a psychiatrist
from Missouri (in Thailand) and a couple from Louisiana (in Australia), all
prominently raised the issue of possible suicide.

Finally, some persons with depression complain of bodily discomforts that
have no demonstrable physical cause, including headache and joint pain. As
these also can be features of DCS, report of them post-dive could result in an
inappropriate trip to the chamber.

Issued related to pharmacological treatment:

Drugs are frequently used to treat depression, and this raises additional
concerns. Divers taking any medication should routinely investigate reported
side effects.

Commonly prescribed antidepressants include three major classes: selective
serotonin reuptake inhibitors (SSRIs), tricyclics/tetracyclics/heterocyclics
(TCAs/HCAs), and monoamine oxidase inhibitors (MAOIs), along with a few
uniquely acting compounds.

In general, SSRIs are currently more popular than the others due to their
relatively greater safety (including in overdose) and tolerability, although
they do cost more. MAOIs tend to be less frequently prescribed, in part because
their interaction with certain foods, beverages and medications can cause
severe high blood pressure. Examples of each class can be seen in Table 1.


Table 1
Prescribed Antidepressants
SSRIs:

Celexa® (citalopram)
Luvox® (fluvoxamine)
Paxil® (paroxetine)
Prozac® (fluoxetine)
Zoloft® (sertraline)

MAOIs:

Nardil® (phenelzine)
Parnate® (tranylcypromine)

TCAs/HCAs:

Adapin®, Sinequan® (doxepin)
Aventyl®, Pamelor® (nortriptyline)
Elavil®, Endep® (amitriptyline)
Ludiomil® (maprotiline)
Norpramin®, Pertofrane® (desipramine)
Remeron® (mirtazepine)

Others:

Desyrel® (trazodone)
Effexor® (venlafaxine)
Wellbutrin®, (bupropion)

Although the risk is very low, perhaps most worrisome is that the majority
of medications prescribed for the condition have been shown to be associated
with seizures, most particularly the SSRIs at high doses. The almost certain
lethality of a convulsion underwater requires that serious attention be paid
to this finding.

A second disturbing effect is drowsiness and reduced alertness, an adverse
reaction known to occur with a number of antidepressants, notably the
TCAs/HCAs. The SSRIs have this problem as well. Thirteen percent of patients with
major depression treated with the world's most widely prescribed antidepressant
(an SSRI) reported sleepiness, while research studies have demonstrated that
such drugs can lead to decreased vigilance. Their effects can hinder higher
cognitive functions as well, such as ability to master complex spatial tasks
and to recall information learned a short while earlier.

Obviously, these medications impact on brain chemistry at ambient
atmospheric pressure. It is not unreasonable to suspect the possibly that their
effects could be potentiated by increased partial pressures of nitrogen and additive
with those of nitrogen narcosis.

Drowsiness, dizziness, concentration disturbance and deficits in more
complex cognition are among the reasons that package inserts for antidepressants
contain warnings that the drug may impair the mental and/or physical abilities
required for the performance of hazardous tasks, such as operating machinery
or driving a car (and scuba?). The addition of medication-induced compromises
of alertness, concentration and decision-making efficiency to impairments of
these functions caused by the depression itself is quite troubling given a
multitask recreation like scuba.

Several studies suggest that increased brain levels of serotonin correspond
with increased levels of fatigue during exercise, under some conditions
diminishing endurance by as much as 32 percent. Again, adding deficits in stamina
caused by SSRIs to those already inherent in depression could spell disaster
in a scuba emergency.

An unusual and typically mild but nonetheless worrisome side effect of
certain drugs used to combat depression, notably the SSRIs, can be a tendency
toward increased bleeding. During scuba, blood vessels in the ears, lungs and
sinuses are subject to strain as a result of changes in pressure related to
depth and equalization techniques. What under normal circumstances might be
undetectable bleeding could under the influence of antidepressants result in
bleeding with accumulation and harm to tissues. And, this bleeding is not always
obvious or painful; in fact can be hidden and painless. If the diver is also
taking other drugs known to interfere with clotting, such as non-steroidal
anti-inflammatories like aspirin and ibuprofen, there is a further increase in
the risk of bleeding.

Side effects of some antidepressants can mimic DCS. All classes of
antidepressants have shown adverse reactions involving the central nervous system
such as headache, weakness and fatigue, dizziness, incoordination, abnormalities
of vision, and numbness and tingling of the extremities.

The above discussion of medication could leave one with the impression that
taking antidepressants automatically sinks the diver under the weight of
adverse reactions. This is not necessarily the case. Many persons who take these
drugs tolerate them well, and what side effects they do experience pass after
several weeks of use. Moreover, altering dose size, the times at which doses
are taken, and other steps sometimes can manage persistent side effects.
Finally, the wide variety of available antidepressants allows the diver and his
doctor to try different ones until adverse reactions are minimized.

Still, these are medications and they will have enduring, problematic side
effects in some persons. As such, each individual must carefully monitor how
or he responds to a prescription over time before engaging in activities for
which side effects could pose a risk.

What can we prove?

Frankly, next to nothing. Sadly, there has been exceedingly little
investigation of how depression and antidepressant drugs really affect the diver.

One animal study has suggested that increased serotonin levels related to
SSRIs may contribute to high pressure nervous syndrome, a disorder sometimes
seen in very deep dives on helium mixes but of very minimal relevance to the
recreational diver. And, while it might be expected that chemicals that
stimulate the brain (like serotonin and caffeine) could predispose to oxygen
toxicity, a study on rats found that caffeine in fact reduced the risk.

There is only a single study I am aware of that assessed the interaction
between a drug that acts on the human brain and the effects of partial pressures
of nitrogen typical of recreational scuba. This involved dimenhydrinate
(e.g., Dramamine Original Formula®), and demonstrated impaired alertness &
performance. Although dimenhydrinate has been shown to interact with certain
neurochemicals known to affect mood, including serotonin, norepinephrine and
dopamine, the exact mechanism of its effects under increased partial pressures of
nitrogen is not entirely understood.

Where does this leave the recreational diver with depression and those
advising him about safe scuba?

There appear to be 3 basic approaches to this question:

1. Assume that depression and the drugs used to ameliorate it do not pose a
danger to scuba great enough to advise against diving:

This position is not defensible given what we know about the topside dangers
of both depression and antidepressants. Because of a dearth of research and
necessary reliance on theory, a number of dive medicine experts have
expressed serious reservations about the wisdom of diving while suffering from
depression, especially while medicated. The phenomenal popularity of modern
antidepressants and their wide prescription by physicians not expert in their use
suggests a somewhat cavalier attitude about these medications. Such an attitude
can have grave result when it comes to pursuits like scuba.

2. Assume that depression and the drugs used to ameliorate it pose a danger
to scuba great enough to advise not diving until the condition has entirely
lifted and medication discontinued:

Qualified medical professionals rendering their best judgment in the absence
of supportive science should not be too readily faulted for possibly erring
on the side caution. Liability issues no doubt contribute to this stance, but
at the least it does seem prudent and ethical medicine, whose overarching
dictum is, "First, do no harm."

Along this line, in May 2001, based on a manufacturer reported seizure
frequency of .4 percent at the highest recommended dose, the UK Sport Diving
Medical Committee specifically advised against diving while using Wellbutrin®,
deeming the risk "grossly excessive." It also made this recommendation regarding
Zyban®, an aid to smoking cessation treatment that contains the same advise
against diving.”

While it could be argued that this position is unduly conservative, it is
not without a defense.

3. Assume that depression and the drugs used to ameliorate it do not
preclude diving provided that: (a) mental status examination demonstrates the
condition to be well controlled; (b) the diver on medication has been on for an
extended period and side effects dangerous to scuba are neither reported nor
observed upon careful examination; (c) there are no other contraindications in
the clinical picture; and, (d) the diver feels he is up to it and fully
comprehends the remaining risks.

I suspect that most divers will find this latter perspective the most
appealing, and it is the one I’d want applied to myself if ill. It also seems to be
gaining interest in the dive medicine community. A version appears on Diving
Medicine Online (also reproduced in part as a DAN Diving Medicine Article).
Dr. Campbell’s position on fitness to dive in persons with depression is that
decisions be based on the "merits of each case." This includes considering
"... the type of drugs required, the response to medication and the length of
time free of depressive or manic incidents" and "... 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." He goes on to say
that, "Most, particularly those divers who have responded well to medications
over a long term, probably could receive clearance to dive."

In any such deliberation, it is important that the diver be entirely honest
with treating sources, training agencies, dive ops and himself.

The jury is still out. For the foreseeable future, decisions on the
recreational diver with depression will remain individual determinations meager of
science and rich of professional judgment.

© Doc Vikingo 2003

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