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Depression & Psychotic Features
Last edited |
10/21/2008
There
are little data regarding the prevalence of associated psychotic features in
subjects with major depressive disorders in the general population
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One study found that the lifetime prevalence of
psychotic symptoms in subjects who at one time had met criteria for
major depression was 14% (lifetime prevalence of major depressive
episode with psychotic features at 0.6%) (9).
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A number of studies have reported that psychotic depression
differs from non-psychotic depression in several respects (10-13).
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A recent clinical study that compared patients with DSM-III-R
major depressive disorder with psychotic features to those without psychotic
features (13) reported that the delusional patients were younger, more
frequently had a previous history of delusions and more frequently had feelings
of worthlessness.
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Another study did not find differences between psychotic and
non-psychotic depressed subjects in their clinical features (age of onset,
duration of the episode, frequency) (14).
Our
study reports on the prevalence of DSM-IV major depressive episodes with and
without psychotic features in the general population of five major western
European countries.
Research
We evaluated:
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which depressive symptoms were more likely to
be associated with psychotic features in the general population
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and the relative
contributions of age, gender and chronicity.
The participants in the five countries were interviewed by
telephone with the broader purpose of investigating sleep habits, sleep-related
symptoms, and psychiatric and sleep disorders.
The target population was all
non-institutionalized residents ages 15 years or over.
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In the first stage, the
population was divided according to its geographical distribution as per the
official census data for each country,
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then telephone numbers were
randomly drawn. In the second stage, within each household a member was selected
as a function of age and gender using the Kish method (16) in order to maintain
the representation of the sample and to avoid bias related to non-coverage
error.
We excluded potential
participants who had insufficient fluency in the national language, who had a
hearing or speech impairment or with an illness that precluded the feasibility
of an interview.
The participation rate was:
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79.6% (4,972 of 6,249 eligible
individuals) in the UK;
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68.1% (4,115 of 6,047 eligible
individuals) in Germany;
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89.4% (3,970 of 4,442 eligible
individuals) in Italy;
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83% (1,858 of 2,234 eligible
subjects) in Portugal;
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and 87.5% (4,065 of 4,648
eligible individuals) in Spain.
Overall, 18,980 subjects
participated in the study.
The overall participation rate
was 80.4%.
This sample is representative of
205,890,882 inhabitants.
Results
This study investigated the
associations between depressive symptomatology and psychotic features in a
sample of 18,980 subjects in five European countries.
Prevalence
The current prevalence of
DSM-IV major depressive episode was set at 2.4% in this sample.
About 19% of
these subjects with a major depressive episode had psychotic features yielding
a prevalence of major depressive episodes with psychotic features of 0.4% in
this sample.
Thus, psychotic major depression is a relatively common disorder
affecting four out of 1000 individuals.
Severity and Psychotic Features
Surprisingly, although the
severity of the depression is an important issue for the presence of psychotic
features, we found a considerable number of subjects with mild or moderate
major depressive episodes who had psychotic features and other subjects who
did not have enough depressive symptoms to fulfill the criteria for a major
depressive disorder.
As many as 10% of
subjects with two depressive symptoms had psychotic features.
This association cannot be
fully explained by the presence of a bipolar disorder or another psychotic
disorder: these two disorders accounted for 34% of the association.
Other
mental and neurological associations
Several other mental and
neurological disorders were associated with psychotic features in subjects who
had depressive symptoms but did not meet all the criteria for a major
depressive episode.
Namely, we found many subjects
who had:
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obsessive compulsive disorder,
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post-traumatic stress
disorder,
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panic attacks,
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history of abuse
of alcohol.
In non-depressed subjects who
had psychotic features, an identifiable mental or neurological disorder was
found in at least 60% of cases.
Depressive
symptoms associated with Psychotic Features
When examining individual
depressive symptoms, we found that subjects who reported feelings of
worthlessness or guilt were the most likely to have psychotic features,
confirming the results in a recent clinical study (13).
However, the severity of this
symptom was not related to the presence of psychotic features.
Guilt may be a useful cue to
delve more deeply into the presence of psychotic features.
Characteristics of Depression
with Psychotic Features
We also found that subjects with
a major depressive episode with psychotic features were more likely to have
consulted in the past for depression, suggesting a possible recurrence of the
disorder.
They had also a longer duration
of the major depressive episode than the subjects without psychotic features.
This is in line with findings
reported in clinical studies where patients with a major depressive episode with
psychotic features are more likely to have recurrent depressive episodes, and
episodes of longer duration (10-13).
These data suggest the duration
of episode may increase the risk of developing, delusions, perhaps through a
biologically based process.
However, we did not find that
psychotic features were associated with younger age as suggested by another
study (13).
Conclusion
This study
underlines the extent of depression with psychotic features.
This has a double
impact, namely, on patients diagnosis identification and on treatment.
Contrary to a common belief, depression with psychotic features is not
associated with severity.
This last point raises the prospect that these
patients are seen by general practitioners and remain inadequately treated.
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Sleep-EVAL
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