THE 1987 INTERNATIONAL CONFERENCE OF THE SYSTEM DYNAMICS SOCITY.. GHINA 1
DEPRESSION, PERCEPTION AND COGNITION
Karen J. Adler
Swiss Federal Institute of Technology
Robert L. Eberlein
Shanghai Institute of Mechanical Engineering
ABSTRACT
Depression is one of the leading psychiatric disorders today. A new
approach known as cognitive therapy has made significant gains in trea-
ting depression by helping people change their understanding of their
actions and environment. The approach is based on the assumption that
it is primarily a person's thought process. concerning circumstances, ra-
ther than the circumstances per se, that are central to depression. In
this paper, we develop a system dynamics. model that can be used to ex-
Plain more fully the dynamics of the processes which lead to depression,
as well as the dynamics of getting better. The model is used as a ve-
hicle to integrate the many facets of cognitive therapy into a coherent
classification of the technique. A variety of case studies are used as a
basis of model development and evaluation. The model is simple enough
to be understood by people who do not have formal training in system
dynamics. As such, it serves ag both a valuable tool for therapists
practicing cognitive therapy as well as a means of communication to the
general public of the nature of cognitive therapy.
INTRODUCTION
Almost everyone experiences depression to a greater of lesser degree at
some point in his or her life. In fact, depression is the leading mental
health problem today. In the 1960s, a relatively new theory of de-
pression led to the development of cognitive therapy (Beck, 1967, 1976,
Beck et. al. 1979).. Clinical research is proving cognitive therapy su-
perior to traditional methods in helping people who are suffering from
depression. Depressed patients in cognitive therapy not only respond
faster, but also’ tend to experience sustained relief for longer periods of
time compared to patients in pharmacotherapy and other, established and
accepted methods for treating depression (Rush et. al.,1977)
Cognitive Therapy is a non-drug therapy based on a structured view of
the interaction between an individual's thoughts, perceptions, feelings
and actions. This paper presents a brief overview of the cognitive
theory of depression and develops a simulation model that captures the
essence of the structured theory. The simple model of depression offers
a coherent framework in which to consider the theory's assertions.as to
the underlying causal structure of depression, and, given those assump-
tions, to probe the potential impacts of different treatments. As.such,
therapists can use the model as a powerful communication tool as well as
an aid in developing strategies for treating patients.
The model and results presented in this paper are preliminary. The
model attempts to integrate the elements of the cognitive theory of de-
pression and formalise the function of cognitive therapy in the treat~-
2 “THE 1987: INTERNATIONAL CONFERENCE OF THE SYSTEM DYNAMICS SOCITY. CHINA
ment of depression. It is based on theory and case studies presented
in the literature.
COGNITIVE THEORY OF DEPRESSION
The cognitive theory of depression is based on the tenet that an indivi-
dual's moods and emotions are ultimately dependent on how the individual
thinks, hence the name "cognitive" theory. Cognition refers to how ‘peo-
ple think, their perceptions, beliefs, and the way in which they inter-
pret the world around them. Specifically, cognitive theory asserts that
cognition, or thought, determines the way in which a person perceives
their environment: erroneous thought patterns and beliefs cause dis-
tortion in expectations as as well as erroneous perceptions. The dis-
torted perceptions tend to evoke unpleasant emotions and reinforce er-
rorieous cognitions. "Erroneous" is used in this case to label a belief or
perception that has no basis in fact or is a distortion of fact. For ex-
ample, if a person beliéves he is exceptionally clumsy,.he will expect to
be clumsy. His attention will tend to focus more on any incidents in
which he is the least bit awkward, than on incidents in which he is
graceful. His heightened and distorted perception of clumsiness evoke
feelings of inadequate, or perhaps of frustration, and reconfirm his be-,
Hef about being awkward. Quite possibly, upon comparison, the person
may prove to be no more clumsy than the average fellow.
In essence, the cognitive theory of depression claims that cognition
creates emotion and mood, and that negative emotions foster heightened
_awareness to negative events and result in negative perceptions and
thoughts which inevitably contain distortions. Cognitive theory asserts
that the key to break the unnecessary and unpleasant cycle of depres-
sion is to correct the erroneous patterns of cognition.
Compared to traditional theories of the psychology of depression, the
cognitive theory is empowering. Depression is viewed as a result of a
logical error which the individual is at power to correct. It is the in-
dividual’ that creates or. resolves his depression; he is not a helpless
emotional victim of his innate chemistry, his rigid personality, his he-
reditary, his environment or his drugs.
COGNITIVE THERAPY OF DEPRESSION
Dr. Arron.T. Beck’ (Beck, 1967) began to develop cognitive therapy
upon the recognition that depressed people typically think about thingse
differently than people who are not depressed. He noted that depressed
individuals often put markedly different interpretations on events than
do non-depressed people. Specifically, depressed patients tend to per-
ceive activity and information around them as a negative, personal com-
ment on themselves. Neutral and even positive events become devalued
and perceived to be negative personal statements. This results in the
fact that depressed people are faced continually with erroneous, negative
reflections on themselves (Burns,1980).
THE 1987 INTERNATIONAL CONFERENCE OF THE SYSTEM DYNAMICS SOCITY. CHINA 3.
Most people become depressed when constantly faced with negative state-
ments about themselves. Cognitive therapy does not try to relieve de-
pression that occurs in such a negative environment; rather, it focus
on identifying the erroneous pattern of cognition that create the dis-
torted environment and cause the depression.
The goal of cognitive therapy of depression is to help the patient iden-
tify and change any distortions in his or her patterns of cognition in
order to achieve and sustain improved emotional well being. The the-
rapy relies on the common sense reaction of a person when she learns to
recognise and scrutinize her way of thinking for distortions, and begin
to understand why she tends to respond the way she does; they are
then in a position to change their response by eliminating their cognitive
distortion. The success of the therapy depends upon the extent to _
which an individual can change his or her ways of thinking.
The: key concept in cognitive therapy is cognitive distortion. Dr. D.E.
Burns (Burns, 1980) outlines ten types of cognitive distortions common
in depressed patients which cover the following basic tendencies: to
bias attention to negative .perceptions over positive perceptions; to
discount events not conforming to expections; to over-generalize and
jump to conclusions; to interpret things as negative, personal state-
ments. The therapy helps the patient to recognise the distortions he or
she uses. The careful record of events, thoughts and activities is en-
couraged for feedback ‘to prove the distortions erroneous.
Cognitive distortions are often integrated into incomplete thought and
internalize quickly without conscious recognition. Cognitive therapy
attempts to identify what Beck refers'to as Automatic Thoughts in order
to scrutinize their logic for distortions. Distortions in automatic
thoughts are particularly difficult to identify because they are inter-
nalized so quickly without conscious effort.
Depressed individuals tend to lack the motivation to do activities par-
tially due to underestimating the value derived from the activity. Since
they underestimate the reward from doing things, they have lower in-
centive to act and forego doing things which they otherwise would do if
their expectations of the reward from the activity was undistorted. in
the extreme, the depressed patient will spend days lying in bed for want
of motivation. Commonly, the result of this tendency is increased de-
pression due to feeling useless. In therapy, patients are asked. to. re-
cord their expected pleasure or displeasure from doing activities; this
record is them compared with the actual. pleasure or displeasure they
experienced doing the activity. The feedback offers a proof of the dis-
tortions embedded in their expections.
The patient in cognitive therapy is actively involved in a process of
identifying and eliminating distortions. There are three broad areas of
emphasis: simple recognition of cognitions and distortions; distinction
between expectations and realisation; and the critical evaluation of dis-
torted thoughts. Examples of recognition include the use of a wrist
counter to keep track of the number of automatic thoughts of positive
4: THE 1987 INTERNATIONAL CONFERENCE OF THE SYSTEM DYNAMICS SOCITY. CHINA
. events that occur in a day. Examples of distinction include the compar-
‘ison between the anticipated and actual degree of difficulty and satis-
faction. associated with different activities. Examples of evaluations
include the written record of automatic thoughts and the associated ra-
tional responses to those thoughts. The actual emphasis in a therapy
session varies from individual to individual, depending on ‘his or her
specific needs.
A SIMPLE MODEL OF DEPRESSION
Model Overview
We have developed a simple model of an individual which integrates the
various aspects of the cognitive theory and therapy of depression. In-
cluded in the model are only the essential elements which, according to
cognitive therapy, are important to maintain an individual's mental
health. They.include: Cognition, Cognitive Distortion, Emotion, Acti-
vity and Energy.
Currently, the model is standardized to represent an average person.
In order to apply the model to.a specific individual, certain elements in
the model which currently have standard values would have to be cus-
tomized to represent the unique qualities of that person. The unit of
time used is standardized at one week; in other words, all units are
measurements for a one week time period.
The model of depression, like any model, can be useful only if it is pro-
perly: understood. Unfortunately, the terminology used in models can
easily leave room for confusion. This is because words loosely used in
everyday language, which have perhaps a slightly different meaning for
different people, are used in a model to label a specific concept or ele-
ment important to,the problem at hand. To understand any model, it is
critical to study and exclusively use when thinking about the model the
meaning which the modeler attributes to each term. As a result, a mo-
del defines a common language to discuss the issue of interest, in this
“ease depression.
Phe Basic Feedback Structure
The basic feedback structure of the simple model of depression is illus-
trated in Figure 1. Arrows with plus (+) signs indicate that the two
sconnected elements change in like directions; Arrows with minus (-)
sgigns indicate that the elements change in opposite directions. For ex~
ample, the arrow from Energy to Activity is positive, meaning that Ac--
tivity is positively related to Energy: when an individual has ‘a lot of
energy, he can engage in a lot of Activity. Conversely, when a person
is low on energy, his Activity will be restricted. In both cases, the
changes are in the same direction. In contrast, the arrow from Activity
to Energy is negative, meahing that Energy is inversely related to Acti-
vity.. Activity requires and.thus drains Energy. When a person increa-
‘Seg Activity, she must deplete her Energy. Conversely, when she does
Jess Activity, she has more Energy available for use; the movements are
posite directions. Sie
THE 1987 INTERNATIONAL CONFERENCE OF THE SYSTEM DYNAMICS SOCITY. CHINA 5
Associated Reward
Ce... Activity
£ LD cite
Energy > Ny
Expectation of Perceived
Reward from Reward
Activit:
Y es
+
Mood
Emotional
Well Being
+
Figure 1 The model's simplified causal structure.
It is often difficult to find an appropriate point to start to describe a
model. We will begin by briefly summarising the rough feedback struc-
ture, and then continue with a definition of the basic elements in the
model. It may be helpful to refer to Figure 1 when reading the descrip-
tions.
Figure 1 roughly summarise the thesis of the model, namely that cog~
nition, determines emotions, and that combined they determing expec-
tations. Expectations, in turn, motivate the use of energy for activity.
The perceptions of the reward from the activity evoke emotions and
mood. Mood effects general emotional well being.
The structure of the model can be viewed as two basic feedback loops: a
positive, or accelérating, major loop, and a negative, or regulating,
minor loop. The positive loop connects Emotional Well Being, Expecta-
tions, Activities and Perceptions, and enables accelerating depression or
cheerfulness. For example, when a person is in a good emotional: state
and mood, expectations are rosy, much activity is done, rewards are
reaped and the person is happy with themselves. If the person's emo~
tional well being is a little better than at the start of the cycle, then
each additional cycle will continue to enhance mental health. If at the
end of the cycle, emotional well being is a little less that before, then
the same cycle, becomes vicious and erodes a person's mental health into
the depths of depression. The negative loop between Energy and Acti-
vity, moderates the acceleration, or gain, around the major positive
loop. For example, a person enjoying a rosy cycle will keep adding
activities to his agenda; however, he inevitably runs low on energy
which begins to limit his activity. He adjusts his engagement in activity
until he again has spare energy which, in turn, motivates him to go out
and do something fun. 2
6 THE 1987 INTERNATIONAL CONFERENCE OF THE SYSTEM DYNAMICS SOCITY. CHINA
Cognition
In the model, the concept of cognition is divided into three distinct com-
ponents: Perceptions, Expectations and Distortions. Perceptions repre-
sent the individual's recognition of his environment, including his unique
pérspective and ways of interpretation. Included in the term Perception
is the individual's beliefs, and ideals. In short, it is a person's per-
ception or mental picture of the world around him or her. In the model,
Perceptions are measures of reward from activity and are given in units
of (Warm) Fuzzies per week.
Expectations differ from Perceptions only in that Perceptions are a men-
tal concept of what has happened in the past, where as Expectations are
a mental concept of what might happen in the future. In the. model,
Expectations are a measure of Reward per Activity and are given in
units of (Warm) Fuzzies per Step. They are used as,a motivation to do
activity. In a emotionally depressed state, a person's Expectation of
Reward is low. As a result, the person will not chose to do much ac-
tivity; he does not see it to be worth the value of the energy he would
have to put into it. To some extent, an individual's expections may
replicate his perceptions, but this does not necessarily have to be the
case. For example, a person may have perceived numerous time last week
that after she slept she was no longer tired. She may have the exact
same expectation. for this week. ‘She also may have perceived tremen-
dous pain while running in a marathon; however, in her expectations
for the next marathon, she may. forget about the pain and expect only
the reward of reaching the goal,
The distortion component of cognition will be described later in detail.
Emotions
The concept of Emotional Well Being is used in the model. as a. simple,
composite indicator of general emotional health. It is measured in Smiles
per Week and is simply a three week average of Mood, also measured in
Smiles per Week. For simplicity, Mood is a direct reflection of the per-
ceived Reward, or (Warm) Fuzzies per Week, modified by an effect from
expectation, and by the effects of comparison. For example, when a
person writes a poem, he receives a certain pleasure from it. But the
quality of the ppém may fall short of his expectations and this might
cause some disappointment. Then he may compare its quality to that of
other poems he has’ written and may become less pleased with the poem,
thinking that he really could’ and should have done a better job. His
pleasure might be further decreased by the thought that compared to the
clagsic poems, his poem in really bad. As a final result, he might be in
a sightly depressed mood.
In practice, Emotional Well Being and Mood are commonly the elements
which most readily receive the patients attention and are most commonly
“gommunicated. The measure of Emotional Well Being is intended to
incorporate the essence of Dr. A.T. Beck's Depression Inventory (Beck,
1967). The inventory captures the many symptoms of depression;
THE 1987 INTERNATIONAL CONFERENCE OF THE: SYSTEM DYNAMICS SOCITY. CHINA 7
though the model does not have the fine detail to represent the various
symptoms, it does represent the main concept.
Activities
Two different types of activity are defined in the model: Externally
Motivated Activity and Self Motivated Activity. The difference between
the two is admittedly fine. Externally Motivated Activity is that which
one needs to do for physical existence. Eating a healthful diet and pur-
suing basic hygiene would be examples of Externally motivated activity.
Work, in so far as it supplies resources for basic necessities, is also an
example. Some people take good care of themselves, others are perfectly
content in a state of slight neglect; the extent to which an person ful-
fills his or her basic needs under conditions of normal mental health
varies from individual to individual and can be adjusted in the model.
Self Motivated Activity, on the other hand, is activity engaged in for
pleasure. Climbing Mount Sverest and luxurious dining would be exam-
ples of Self Motivated Activities in so far as they exceed the basic needs
for exercise and nutrition. Standard values for the amount of both ac-
tivities for an average person in good mental health have be chosen for
the current version of the model. Both types of activities are measured
in steps per Week and have an associated Reward per Step.
In the model, Reward from an Activity is measured in (Warm) Fuzzies
per Step. It represents a general unit of measure for the value or plea~
sure a person derives from engaging in any activity relative.to the ef-
fort invested. In other words, it is the motivating force symbolising
what a individual "gets out of doing something". Naturally, the mag-
nitude of the reward from various activities is specific to the preferences
of the individual. Some people place a high value on climbing Mount
Everest, other people would prefer to let such an opportunity pass. In
the model, it is the relative difference in the rewards for the two types
of activities that is of consequence. By definition, Self Motivated Ac-
tivity is standardized with an associated Reward per Step which is twice
that of Externally Motivated Activity. This is based on supposition that
Externally Motivated Activity is done more out of necessity than for
pleasure.
Expectations of Reward per Self Motivated Activity can be distorted per-
ceptions; it is assumed that the Reward per Externally Motivated Ac-
tivity is clearer to define and less likely to be a distortion of past
perceptions. For example, the reward from eating when hungry is imme-
diate and easier to judge than the reward from writing a book. | Distor-
tion will be discuss later.
Energy
At any time,’ a person has a certain storage of Energy. In the model,
the term Energy represents the physical limitations on the individual.
To do any activity requires the Expenditure of Energy, and without
Energy, no activity can be done. The person represented in the model
has a natural ability to replenish energy; it is affected by the person's
8 THE 1987 INTERNATIONAL CONFERENCE OF THE SYSTEM DYNAMICS. SOCITY.: CHINA
Emotional Well Béing, and by the person's satisfaction of basic needs.
For example, a depressed person, or a person who is getting insufficient
sleep will have a weaked ability to replenish their energy. Relatively
low Energy compared to normal inhibits both types of activity, though
the influence on Self Motivated Activities is more severe. At extremely
low levels of Energy, both Self Motivated Activities and. Externally Mo-
tivated Activities are harshly restricted. This would correspond to a
depth of depression that prevents and individual from caring for his
basic needs. Energy is measured in Steps, and under normal, standard
conditions, there is twice as much Energy available than is exerted.
Cognitive Distortion
The notion of cognitive distortion is central to the cognitive theory of
depression and hence to the model. Figure 2 indicates where in the
model distortion can occur (Please refer to Figure 2). Cognitive dis~
tortion pertains solely to a qualitative change in cognition. In the model
Distortion can directly effect only the portion which represents the in-
dividual's cognitive structure. Expectations, Perceptions and Beliefs can
be distorted; Energy, Actual Activity and Actual Reward per Activity
are not cognitive elements and can not be distorted. Two basic types of
distortion can occur in the model: Bias and Exaggeration. The model
identifies six places in the cognitive structure where distortion can di-
rectly effect cognition. Distortion indirectly effects cognition in to
places.
Bias, the first type of distortion, can potentially occur at two places in
the model. It effects the process of cognition by adding or discounting
an error. Depending on Mood, there is a Bias on Expected Reward per
Self Motivated Activities and on Perceived Reward from Activities.
Consider, for example, a person who is in a sour mood. In the model,
this would appear as a low ratio between the person's. Mood and their
normal level of Emotional Well Being. As a direct effect of the person's
bad mood, she might be pessimistic about her prospects for the day, and
if her bad mood persists, she might be very difficult to please. In the
model, her bad Mood will create a discounted Expected Reward per Self
Motivated Activity. Otherwise good expectations will seem a little worse;
otherwise poor expectations will seem a little worse. The worse her
Mood, the more she will discount her expectations. The same effects
works on perceptions. Conversely, if she is in an exceptionally good
mood compared to her normal emotional state, she will be an optimist,
expecting and perceiving everything a little better than she would have
otherwise. Both Biases are dependent on Mood and thus reflects the
fact that a person can be in'a state of normal emotional well being and
still temporarily distort reality.
The second type of distortion effects cognition by Exaggeration. It po-
tentially occurs at four places in the model. This kind of distortion
effectively exaggerates the negative and minimizes ‘the positive under
condition of depression. Consider, for example, a person who is de-
. pressed. In the model, depression is indicated as a low ratio of the
“ individual's Emotional Well Being relative to the his normal level of Emo~
tional Well Being. His depression, independent from his Mood, will cause
Expected Reward
per Externally
Motivated Activity
Actual Reward
per Externally
Motivated Activity Exaggeration
+
Externally Motivated Ne Prva Being
+ fe ‘Activity ya Rerceived Reward
enkegy— +. from Activities mi, Bias from+
+
\C™ elf Motivated . A
Activity
+
‘Actual Rewar
per Self
Motivated
Activity
elief of SgemmenExaggeration to
Personal Percieve: Belief
Ability
Belief of emmenexaggeration on
Ideal Ideal
Expected Reward
per Self Motivated
Activity +B Mood
Bias amy
Mood
Exaggeration
from Emotional
Well Being +
+e Emotional
Well Being
Figure 2 The model's simplified causal stucture with cognitive
distortion.
6 WNIHD *ALIOOS SOIWVNAG WHLSAS SHL 40 AONANTINOO “IVNOLLVNYAINI 2861 FHL
10 THE 1987 INTERNATIONAL CONFERENCE OF THE SYSTEM DYNAMICS SOCITY. CHINA
him to be somewhat pessimistic in both his Expectations and his Pertep~-
tions of his environment. If, for example, his Actual Reward from Ac-
tivity was low, he will perceive it as still lower. If his Actual Reward
was high, he will perceive only a fraction of it. The worse his depres-
sion, the smaller the fraction he will perceive of the total Actual Re-
ward. Conversely, as Emotional Well Being rises above normal,
The Exaggeration from Emotional Well Being also effects the two beliefs
which are specified in the model. The Belief of Personal Ability simply
reflects the beliefs a person acquires over time based on their exper-
jences. For example, when a person consistently perceives that he is
good at writing, he begins to develop the perception that he is a good
writer. This is represented in the model as Belief of Personal Ability
being an average over time of Perceived Reward from Activities, Exag-
geration from Emotional Well Being can effect the determination of Belief
of Personal Ability: This reflects the evidence that a depressed indi-~
vidual is less likely to raise their Beliefs than they are to lower them.
Belief in Ideal reflects a non-personal Ideal of how the individual should
be. In reality, the determination of ideals is complex and not of major
consequence to the dynamics of depression; however, there is substan-
tial evidence (Burns, 1980) that depressed people commonly comparé
themselves to irrational ideals. In the model, Belief in Ideal is defined as
the Actual Reward: from Normal Activity, modified, by an Exaggeration
from Emotional Well Being. When a person is depressed, they exaggérate
their ideal of what their ability to get reward from activities should be.
Even if a person perceives that'he has done something well, upon compar-
ison to his exaggerated ideal, he looks bad and should have done better.
Distortion indirectly affects both expections of External and Self Moti-
vated Activity in so far as the Expectations are based on distorted Per-
ceptions of the Reward from Activities.
MODEL BEHAVIOR
The model is initialized to have an equilibrium with Emotional Well Being
and Externally Motivated Activity standardized at normal levels. Energy
is initialized to maintain the equilibrium. The values were arbitrarily
chosen to represent "normal" emotional health and thus offer a standard
for the purpose of comparison. By definition, at normal levels of Emo-
tional Well Being and Mood, no cognitive distortions exist. Perceptions,
Beliefs and Expectations are accurate. The basic structure shown in
Pigure 1 summarizes the effective elements in the model's initial equi-
librium. If started in equilibrium, the model will continue in equili-
brium, though for most parameter values the equilibrium will not be
stable.
Ig the model is initialized so that the person is slightly depressed, the
person will slowly bounce back to normal Emotional Well Being. The pro-
cess of recovery is as follows (please refer to Figure 2): depression
effects immediate distortion on expectation. The distortion exaggerates
the difficulty and understates the potential benefit of a given activity;
THE 1987 INTERNATIONAL CONFERENCE OF THE SYSTEM DYNAMICS SOCITY. CHINA 11 |
consequently, activities that would be rewarding are not undertaken.
Self Motivated Activities are. restricted, and: Externally Motivated Ac-
tivities fall slightly. As a direct result, Energy is conserved, and the |
total Reward from Activity drops. After a slight perception delay, an |
even lower reward is perceived due to distortion, and it evokes a drop
in Mood. The drop in Mood, nevertheless, is not as low as the initial de- |
pression and thus effects a rise in Emotional Well Being. Energy re~
covery is slightly hindered due to the initial lower Emotional Well Being;
the restricting efféct’ of slightly lower Externally Motivated Events is
negligible. However, the Energy conservation exceeds ‘reduced reple-
nishment, and as the total Energy rises, the Expected Reward per Self
Motivated Activity rises. More activities are done, and the Perceived
Reward rises, raising Mood and Emotional Well Being. Eventually, as
‘Activity is resumed, Energy expenditures exceeds replenishments and
limits the growth cycle of Activity and Emotional Well Being, and the
initial equilibrium is attained.
Suppose the person represented in the model receives an emotional blow
which puts him in a depressed mood. It’ effects a sharp rise in distor-
tion, reflected in Bias from Mood, and which begins to erode Emotional
Well Being. Decreased Expectation of Reward per Self Motivated Activity
limits Activities reflected in decreased Perceived Rewards. Decreased
Perceptions define a quality of Mood which, depending on the magnitude
of the changes, is even lower than before and further erodes Emotional
Well Being. If the effects of depression are sufficiently strong, low
Emotional Well Being and Decreased Externally Motivated Activity inhibits
Energy replenishment faster than curtailed Activity conserves Energy.
It results in a spiralling down of the level of Energy until low Externally
Motivated Activity further restricts Energy replenishment. Lack of
Energy eventually curtails Activity so that the little energy that is still
expended, primarily for Externally Motivated Activities, is replenished.
The person represented in the model settles into an equilibrium where j
his Energy level in very low. Pessimistic and not motivated, he neglects
his primary care and does not engage in activity which brings him
pleasure. His mood is foul and his depression deep. In the extreme,
Energy, Activity and Emotional Well ‘Being can be so low as to effectively
correspond to suicide. i
THERAPY OPTIONS
We have referred to three broad areas of emphasis in cognitive therapy:
recognition of cognition and distortion, distinction between expectations
and realisations and “critical evaluation for disfortion. The use of cog=
nitive therapy techniques to remove cognitive distortion can be reflected
at various places in the model. The use of the techniques fosters re- {
covery of the depressed individual described in the previous summary of
the model behavior. Removal of all distortion enables a quick recovery;
limited success or application of therapy enables only a slow and partial i
recovery.
The effect of recognition of automatic thoughts in therapy can be cap-
tured in the model by altering the distortion of exaggeration from Emo-
12 THE 1987 INTERNATIONAL CONFERENCE OF THE SYSTEM DYNAMICS SOCITY. CHINA
tional Well Being on expectations and on perceptions. In the model, if
therapy enables the patient to recognise and eliminate 20 percent of his
automatic thoughts, the lowered distortion initiates partial recovery but
the patient remains at below normal Emotional Well Being. This is due to
the fact that the rémaining distortion is strong enough to hold the pa-
tient in a state of low energy and depression.
The effect of distinction can be reflected in the model by modifying the
distortion affecting expectations of rewards. Again, a 20 percent suc-
cess in the patients ability to recogrize his distortion on expectations
alone will foster partial but not complete recovery; however the com~
bined effect is enough to spark a slow, but complete recovery. The
effect of critical evaluation can be reflected by modifying the bies from
Mood, the distortion on. Belief and the Distortion on Ideal.
The important insight is.that system by virtue of its structure has the
ability to recover from depression if the facters that erode energy do
not overpower those which replenish it. In heathly equilibrium, dis-
tortion does not exist; as depression grows, distortion rises and has to
increasingly powerful effect to drain the’ system of Energy, Activity and
Emotional Well Being - precisely that which is needed for recovery.
Distortion effectively becomes a leech on the person. The distortions
that build during a onset of depression, once lessened enough for the
person's inherent energy to build, become mastered by the person as he
or she recovers. Cognitive therapy's success at helping the patient
xemove distortions effectively treats the cause of the process of depres-
sion.
EXTENSIONS
The model we have developed is a preliminary and aggregated represen-
tation of the process of depression. ' More attention needs to be given to
the finer structure of the characteristics of depression. Specifically,
the influence of suicidal tendencies are prevalent and important in- the
formal treatment of depression, and their dynamics needs further explor-
aticn. Functionally, therapists treat patients with suicidal tendencies
differently from those without.. The reasons therefor are obvious, but
the question remains whether the distinction is important to the modeling
of depression.
Self esteem and seli confidence have not beer. incorporated explicitly into
the model, yet ‘it is clear’ that they are fundamental to depression. We
have lumped these concepts into Emotional Well Being. However, emo~
tional well being does not capture all the subtlety of self esteem and self
confidence. The issue of internalization or personalization: Persons
with low self esteem tend to see negative events as reflections on them~
selves. In thé model, we have captured this through cognitive distor-
tion on beliefs, yet this does not capture the patient's selective con-
sideration of events as reflections on the individual.. The model in its
present form does not consider the impact of confidence of the indivi-
dual's quality of interaction and subsequent rewards, therefrom. It is
clear that confidence effects the person's quality of activity, but again,
THE 1987 INTERNATIONAL CONFERENCE OF THE SYSTEM DYNAMICS SOCITY. CHINA 13
it is unclear if the effect is of critical to the structure of depression.
In the model, the planning process of the individual is not explicit.
Individuals do, or do not, engage in activities because the activities are
expected to be of some value relative to the effort required. In the
model, this has been incorporated under the concepts of Energy and
Reward Expectation. Cognitive therapy is concerned with helping people
realistically evaluate these costs and benefits. Ultimately, the balance
stuck between reward and effort determines the individual's experiences.
The detailed structure of the planning. process and its impact on the
cognitive structure of depression warrants further study.
CONCLUSIONS
The cognitive theory and therapy of depression has made significant
gains in the understanding and treatment of depression. The simple
model developed in this paper captures the essence of the cognitive
theory of depression. It offers a coherent framework with which to com-
municate and explore the assumptions and claims of the theory and evi-
dence from practice. Further, it serves as a powerful communication
medium for therapists as well as a structured tool to aid in the deve-
lopment of strategies for treating patients
The inodel captures the cognitive theory view of depression as a symp-
tom, or behavior over time, of an underlying problem in the structure of
thought. It shows depression as a process that halds an individual in a
state of relatively low energy, inactivity and pessimism compared to that
which is normal for that individual. The model illustrate how people who
are normally cheerful as well as those who are normally morose can fall
into the depression. In the model, the individual's depression is created
internally, or "endogenously", as a result of cognitive: distortions, -ra-
ther than as a result of an outside force, such as a depressant drug.
The cognitive therapy processes applied in the model confirm the
inherent consistency of the theory and offer further evidence for its
support.
REFERENCES
Beck, A.T. (1967), Depression: Clinical, Experimental and Theoretical
Aspects, Harper & Row, New York. Republished (1972) as Depres-
sion: Causes and Treatment, University of Pennsylvania Press,
Philadelphia.
Beck, -A.T. (1976), Cognitive Therapy and the Emotional: Disorders,
International University Press, New York.
Beck, A.T. (1979), Cognitive Therapy of Depression, Guilford Press,
New York.
14 THE 1987 INTERNATIONAL CONFERENCE OF THE SYSTEM DYNAMICS SOCITY. CHINA
Burns, D.E. (1980), Feeling Good, William Morrow and Company, New
York.
Rush, A.J., Beck, A.T., Kovacks, A., and Hollon, 8. (1977), "Com-
parative Efficacy of Cognitive Therapy and Pharmacotherapy in the
Treatment of Depressed Outpatients", Cognitive Therapy and Re-
search, Vol. 1, No. 1, pp 17-38.
1 The term Warm Fuzzies is originally from an American, well-loved short
story by an unknown author.
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