Anxiety
and Depression Co-morbidity Rates
Michael
Bell
Carlow
University
Anxiety and Depression Co-Morbidity
Rates
Introduction
According to the Diagnostic and Statistical Manual of Mental Disorders, fourth
edition (DSM-IV; American Psychiatric Association. [APA], 2000) depression is
defined as a mood disorder. The mood
during a depressive episode is often described as sad, hopeless, and discouraged. Other symptoms of depression can include
insomnia or increased need for sleep, lack of interest in things that were once
found pleasurable, low sex drive, decreased or increased appetite, agitation,
tiredness, and fatigue (American Psychiatric Association, 2000).
Anxiety is defined as “an abnormal and overwhelming sense of apprehension and fear often
marked by physiological signs (as sweating, tension, and increased pulse), by
doubt concerning the reality and nature of the threat, and by self-doubt about
one's capacity to cope with it” (Merriam-Webster's
Collegiate Dictionary (11th edition), n.d., pg.107). The DSM- IV states that the criterion
for Generalized Anxiety Disorder (GAD) includes excessive anxiety and worry
which occurs for at least 6 months. GAD
is characterized by the subject finding it difficult to control the worry and
it typically presents the following symptoms: restlessness, fatigue, trouble
concentrating, muscle tension, insomnia, and irritability (American Psychiatric
Association, 2000).
Narrow, Rae, & Rieger, 1988 found
that anxiety affects nearly 19 million Americans. A second study suggests that
the incidence rate of anxiety is nine cases per 1000 persons per year (Murphy, Oliver, Monson, Sobol,
& Leighton, 1988). The DSM –IV suggests that anxiety disorders are one of
the most prevalent disorders diagnosed (American Psychiatric
Association, 2000).
Anxiety and depression, if left
untreated, can lead to serious psychological and health consequences. Untreated
depression can increase the chance of risky behavior such as drug or alcohol
addiction, can create issues with relationships, affect job performance, make
it difficult to overcome serious illnesses, and even result in suicide (Liew,
2012). A recent study suggests that the
odds of having at least two chronic health conditions increases with the level
of depression (Liew, 2012). Rehna,
Hanef, and Tariq,2012 found that cognitive errors have significant positive relationship
with anxiety in both depressed and non-depressed samples. The
results showed that depressed participants exhibited numerous types of
cognitive errors.
Studies suggest that cognitive
behavioral therapy is very effective in the treatment of depression and anxiety
and may prevent mildly depressed individuals from progressing to advanced
stages of depression (American Psychological Association, 2010). Other
treatment options for anxiety and depression include systematic
desensitization, psychotherapy, and medication (American Psychological
Association, 1997.)
A recent study suggests that in 57% of people
who have depression, anxiety disorders preceded the depression and that in 18%,
depression preceded their anxiety disorders disorder ( Lamers, van Oppen, Comijs, Smit,
Spinhoven, van Balkom, & Penninx, 2011).
There
is also a suggestion of comorbidity with depression. Another recent study found
that of subjects with a depressive disorder, 67% had a current and 75% had a
lifetime comorbid anxiety disorder. Of subjects with a current
anxiety disorder, 63% had a current and 81% had a lifetime
depressive disorder ( Lamers
et. al, 2011).
The purpose of this study was to examine
the relationship between anxiety and depression.
Methods
Participants
Ninety-four friends and acquaintances
of graduate students in a research methods class participated in the study.
Participants were collected by a sample of convenience. All participants were over the age of
eighteen. Participants had no known mental
health concerns.
Instruments
This study used the Costello-Comrey
Depression and Anxiety Scales (CCDAS; Costello & Comrey, 1967). The purpose
of the CCDAS is to measure anxiety and depression. “The depression scale [of the CCDAS] has
excellent internal consistency, with split-half reliabilities of .90;
split-half reliability for the anxiety scale was .70” (Costello & Comrey,
1967, pg. 213). The CCDAS has fair concurrent validity. “Its anxiety scale is correlated with the
Taylor Manifest Anxiety Scales and the depression scale is correlated with the
depression scale of the MMPI. There is a small to moderate correlation between
the CCDAS and social desirability, suggesting some response bias may be
present” (Costello & Comrey, 1967, pg. 213).
Procedures
Sixteen graduate students in a research
methods class approached friends and acquaintances using a sample of convenience.
Participants had no known health concerns and were age eighteen or older.
Participants were provided with informed consent. Participation in the study was used as
consent. Participants were given the CCDAS and were instructed to complete it
to the best of their ability. Students collected the CCDAS in a manner to
insure confidentiality and anonymity. Scores were calculated according to the
instructions provided.
Results
Data was analyzed using a software
package that calculated the Pearson correlation coefficient. The results of
that analysis revealed a moderate relationship between depression and anxiety (r=0.41, p=.01, two tailed). The
results indicated a significant finding for this study of ninety-seven
participants.
Discussion
This study examined the
relationship between depression and anxiety using a sample of convenience of
ninety-seven participants. The results revealed a moderate relationship between
depression and anxiety that was significant (r=0.41, p=.01, two
tailed).
The results of this study are
somewhat consistent with previous research. Numerous prior research studies
suggest that there is a strong positive relationship between anxiety and
depression. Murphy, Oliver, Monson, Sobol & Leighton, 1988, found that
nearly 50 percent of all depression cases also had anxiety associated with
them. This study found a positive relationship with only a seventeen percent
co-morbidity rate.
The limitations of this study
include a small sample size, and a sample of convenience. Participants were only administered one test
per subject. It is unknown if the participant’s
anxiety or depression was due to situational factors because the measurement
was used at one point in time.
Future research should use a larger
sample size as well as a random sample, and multiple measurements across time
to attain a more accurate measurement of anxiety and depression.
This study examined the relationship
between depression and anxiety using a sample of convenience of ninety-seven
participants. The results revealed a moderate relationship between depression
and anxiety that was significant (r=0.41,
p=.01, two tailed).
References
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