Brief Lecture Notes for Unit 8

General comments about the affective disorders and their etiology

By most accounts, depression has a greater prevalence than any other disorder, though some very recent studies suggest that the mild anxiety disorders are now slightly more common.  (In any event, depression and anxiety are so comorbid that mild forms of either almost invariably coexist with the other.)  For this reason, depression is often known as the "common cold of mental illness" -- subclinical depression is a more or less universal experience, with 1/4 to 1/3 of college students showing symptoms at any given time.

The spontaneous remission rate for clinical depression is very high (70% to 95%, usually within a 3- to 6-month period) -- astonishingly high as compared to most other mental illnesses.  Yet, the recurrence rate is also very high (about 50% within a ten-year period).  This points to cyclicity in depressive disorders as well as the probability of a biochemical component -- about which we'll learn more in this unit.

Some demographics related to depression:

  1. Prevalence is strongly linked to birth cohort.  For instance, those born since 1980 are over 10 times more likely to have had a major depressive episode than those born prior to 1920, even though the latter group has had four times as long to get depressed, and despite the fact that (at least prior to 9/11/01) things were far easier and better for the twentysomething of 2002 than for her/his counterpart of 1942!  The average age of onset for depression has been steadily decreasing for decades -- at one time, childhood (preadolescent) depression was so rare that many psychiatrists believed it could not really exist, while now it is commonplace.  Why?  (Click here for one theoretical schema.)
  2. Prevalence is strongly related to gender.  Women are about twice as likely as men to experience at least one major depressive episode in their life (about 1 in 5 women, compared to 1 in 10 men).  Why?
  3. Prevalence is also strongly linked to culture.  Conventional (unipolar, see below) depression is much less prevalent among "traditional" cultures and subcultures;  for instance, the rate of depression among the Amish is about 1/10th that of the general American population. Why?

All of the above suggests (as expected) that both biological (genetic) and cultural factors interact to produce the etiology of depression.  There appear to be depressogenic cultures, epochs of history, and social roles.  See text page 258, Box 7-2, for some speculations about why depression may be on the rise in what (at least until recently) were paradoxically "good times".  For my own thoughts on this matter, click here.  Also review information on generational cohorts for a view on cyclicity in depression.

Note that we can ask this question in the reverse way:  why isn't depression more common than it is, given the hardships and challenges of life?  Understanding common defenses against depression is an important part of a comprehensive theory as well -- we'll take a brief look at the growing positive psychology movement that attempts to do just that.

Symptoms of depression

Because of the high prevalence of depression and because of the risk of suicide, depression screening is as important as routine screening for common physical illnesses.  There are four symptom clusters that are usually examined in depression screening:

  1. Affective symptoms (which most closely define the category) include the major components of sadness and emotional numbing.  Typically, depressed moods vary with the circadian rhythm as well as with longer rhythms like the seasonal cycles of light and darkness.
  2. Cognitive symptoms include distortedly negative (pessimistic) views of the self and of the future.  These lead to selective perception and, ultimately, to a self-fulfilling prophecy effect.
  3. Motivational (behavioral or volitional) symptoms involve decisional paralysis and difficulties in initiating life activities (passivity).
  4. Somatic and physiological symptoms involve a loss of interest in normal life activities (diminished hedonic value) and disruptions in sleep patterns.

See text, page 253 (Box 7-1) for an example of a depression screening inventory.

Classifying the affective disorders

To classify the affective disorders, we need to understand some key terms:

  1. Unipolar vs. bipolar:  unipolar affective disorders are those that involve mood distortion in a single direction only.  Usually that direction is that of depressed mood, and in this class, when we speak of "unipolar depression" or "unipolar affective disorder" we will generally be referring to the same thing.  In fact, the opposite state (pathologically elevated mood, or mania) also exists, but usually not by itself.  Rather, nearly all (though not quite all) manic states are part of a cyclic, bipolar condition that involves both abnormal highs and abnormal lows.  The condition of hypomanic disorder does involve unipolar mania (no depression) but is extremely rare.
  2. Exogenous vs. endogenous:  We've met these terms before in our discussion of the anxiety disorders.  Exogenous depression results from negative life events;  endogenous depression seems to "come out of the blue" even though life is not outwardly negative (and is therefore probably the result of a biochemical problem).
  3. Episodic vs. chronic:  Episodic depression "comes and goes" (the extreme lows lift by themselves within 3 to 6 months), while chronic depression is a more constant condition.  Usually, the troughs of episodic depression are lower (greater life disruption, greater suicide risk).  While in a theoretical sense these are opposite conditions, in fact it is possible to experience both simultaneously -- to have an episodic depression superimposed on a chronic one, as we'll see.
  4. Self-limiting depressions are those that "cure themselves" (within a year or less) with no evidence of (at least short-term) recurrence. 

With these terms in hand, we're able to classify the affective disorders (see flowchart, in class).

  1. If unipolar, go to 2.  If bipolar, go to 6.
  2. Unipolar condition, mania only:  hypomanic disorder
  3. Unipolar condition, depression only:  see #4
  4. If exogenous and self-limiting, classify as adjustment disorder with depression primary (note that this is often hard to distinguish from adjustment disorder with anxiety primary).  If endogenous or if endogenous but not self-limiting, see #5.
  5. If episodic only, is major depression.  If chronic only, is dysthymia.  If both, is "double depression" (major depression with underlying dysthymia).
  6. If manic episodes involve brief loss of reality contact, is bipolar affective disorder (previously known as manic depression).  If not, see #7.
  7. If the emotional cycles are directly linked to the seasons of light and dark, is seasonal affective disorder (SAD).  If not, is cyclothymia.

Some facts and thoughts about suicide

There is an obvious link between suicide and depression.  Suicide (whether intentional or not) rarely results from other mental illnesses, but it is a frequent result of untreated episodes of major depression.  The tragedy of suicide is that it is almost always "a permanent solution to a temporary problem".  Regrettably, the cognitive narrowing that is associated with major depression often makes it difficult or impossible for the severely depressed person to identify rational alternatives to suicide, even though once the depression lifts, they become obvious and the person may wonder why s/he ever took the idea of suicide seriously.  But in the midst of a major depressive episode, suicidal motivations may become inescapably, obsessively compelling.  Suicide among those under 25, three times more common than it was a generation ago, is now the third leading cause of death in young persons.  Some 25,000 people commit suicide annually in this country.  See text page 292, Table 7-5, for some "fables and facts" about suicide.

Those who attempt suicide can be classified, according to one schema, into three categories:  those with a clear intent to die (about 5%), those who do not really wish or intend to die but who are communicating a dramatic message about their distress (about 60%), and those who are ambivalent (about 35%).  These statistics suggest that most people who attempt suicide would be glad later if their efforts were thwarted.

For some very useful information about depression and suicide from a practical standpoint, click here (will take you outside the UWMC Psychology Web site).  If you are struggling with depression or suicidal ideation right now, don't neglect the free, confidential help this site can provide from an informational and networking standpoint.  Serious depression is a medical emergency and needs to be treated as such.  To do so is not an admission of personal failure.

I won't provide a lengthy discussion of suicide prevention approaches here (see the above hyperlink for some information), but a good general mental hygiene strategy is to make sure you have at least three people in your life (many experts suggest a minimum of five) to whom you could turn in a crisis... who would listen nonjudgmentally and confidentially to you and help you to stay anchored in reality during dark times in your life.  Note that E+ types don't necessarily have more friends of this sort than do E- types, though they have a larger circle of acquaintances as such.  Can you list three such people in your life right now?  If you struggle with depression, it's imperative that you have a pact with these people that they will be unconditionally available for you (and you for them) when times get rough.  Start building that kind of network now (when hopefully you don't yet need it).  Why three?  Because if you only have one such person, what happens if they get sick, are too busy to help, you can't reach them, or they become unwilling or unavailable for any other reason?

Biochemical theories of depression

All forms of depression (clinical or subclinical, self-limiting or not) probably involve, to some extent at least, disturbances in the normal balance of neurotransmitter chemicals in the brain, particularly the important neurotransmitter known as serotonin.  Most drug treatments for depression work by impacting serotonin levels as noted below (see also text page 275, Figure 7-6).

A brief overview about neurotransmitters (if you're completely clueless about this topic, click here and scroll down until you get to information about synaptic transmission -- these are lecture notes from PSY 202):  there are two ways information is transmitted within the nervous system:  electrically within any given nerve cell or neuron (a process known as intraneural transmission), and chemically between neurons (a process called synaptic transmission).  Neurons do not physically touch;  there is a tiny physical space or gap (the synapse) between neurons.  Neurons communicate with one another by passing chemical substances (the neurotransmitters) across the synapse.  When neuron #1 releases such chemicals into the synapse, of course they cannot remain there forever (else neuron #2 could never stop firing);  the chemicals must be reabsorbed by neuron #1 (reuptake) or else broken down chemically into inert substances.  It is this balance between release and reuptake/breakdown that governs overall mood.

In a depressed person, the reuptake/breakdown processes are too efficient relative to the processes of generating and releasing neurotransmitters (specifically with regard to certain particular classes of neurotransmitters, notably serotonin as mentioned above).  Hence, depression is a result of a drop in serotonin levels (insufficient serotonin available).  Activity levels drop, as do mood and one's ability to think quickly and clearly.

Most of us are able to recover from a bad mood because our brains, "recognizing" that serotonin is being dumped, steps up the production of more serotonin to recover normal levels.  But the brain's capacity to bring itself back into balance is limited.  If serotonin levels drop too precipitously, the brain may not be able to recover quickly enough (or recover without the outside assistance of drug treatments), resulting in clinical depression.

Note that the text discusses specific differences in the operation of various antidepressant medications.  For instance, some (the tricyclics) primarily block serotonin reuptake;  others (the monoamine oxidase or MAO inhibitors) primarily block serotonin breakdown.  This is too technical for our purposes, but is helpful information for those interested in medical fields (including psychiatry) and certainly suggests why one should never take more than one type of antidepressant at a time.  St. John's Wort works in a fashion similar to the MAOI drugs and is not a completely benign substance, even though it is not regulated by the FDA.  It can interact with certain foods to produce significant health risks, even though the label on the bottle does not usually say so.  Because this substance can be purchased without a prescription, it is potentially dangerous if misused.  Research this subject carefully before engaging in its indiscriminate use!  See text, page 274:  "When combined with aged cheese, red wine, beer, shellfish... [or blood pressure medication], MAO inhibitors can be fatal."  This applies to St. John's Wort as well.

Cognitive theories of depression

Beck and his followers emphasize cognitive distortions as a primary factor in the maintenance of depression.  These distortions may cause (or help cause) depression;  they almost certainly lead to the maintenance of a depressive state once it exists.

The so-called cognitive triad of distorted thinking involves misperceptions or unrealistic thoughts about the self, the future, and the world:

In a way, these lines of thought can be thought of as "primitive" or "irrational" because of certain characteristics they have in common:

In contrast, mature or rational (adaptive) thought involves matters of degree (I didn't win, but I did better than last time, and I'm improving), is solution-focused (if I can figure out what went wrong, I can improve still more), and suggest hope for improvement or change (I'm not limited by my past).

Unfortunately, to the depressed person, her/his thinking "feels true", and any attempt to "talk her/him out of" being depressed rarely works.  In part this is because of the automatic (overlearned) nature of depressive thoughts, which seem self-validating or self-authenticating.

Cognitive therapy therefore involves the attempt to help individuals identify their depressogenic cognitions, challenge them, and replace them over time with healthier, more rational, more adaptive patterns of thought. It also involves attempts to counteract a pattern of learned helplessness by providing concrete evidence that one's behaviors and choices can make a difference.  One has to build on a person's existing schemata, however, and not merely question all aspects of how a person thinks.  The latter is not only arrogant, but usually backfires because people will naturally defend their existing view of the world, since it is linked to their own sense of self.

A brief look at "positive psychology"

Myers (2000), a leading proponent of the modern "positive psychology" movement, argues forcefully that psychology has been historically focused on pathology, not health.  For instance, an electronic search of Psychological Abstracts, covering more than a century of published findings in the field, yielded nearly 137,000 articles about negative emotions like anger, anxiety, and depression, but only 9,500 articles about positive emotions.  Depression alone was mentioned over 70,000 times in the abstracts;  joy, a mere 850 times!  The surprising result is that we know much more about what can go wrong (and how) with the human experience than what can go right (and how).  The positive psychology movement is an attempt to redress this imbalance.

People are, if opinion surveys can be trusted, much happier than the experts predict them to be.  With a surprising amount of longitudinal consistency, about 30% of Americans describe themselves as "very happy" and an additional 60% as "generally happy" or "fairly happy".  More than 80% describe themselves as more happy than unhappy.

One goal of the positive psychology movement is to help answer the question, "What makes people happy?" and thus "How can human happiness be facilitated?"  Perhaps surprisingly, perhaps not, external circumstances are not the best determinant of happiness.  For instance, wealth is a poor predictor of happiness;  even the very rich are only slightly happier as a group than average Americans.  Longitudinally, Americans today are no happier as a group than their counterparts in 1940.

Far more predictive of happiness is a sense of meaning and purpose.  For instance, people who describe themselves as strongly religious are about twice as likely to describe themselves as "very happy" than those who describe themselves as nonreligious.  It appears that the core element of happiness is not positive circumstances, but an outlook on life that allows one to find meaning in the midst of changing circumstances.

Study Guide

1.  What does it mean to say that depression and anxiety are comorbid?  That depression is the "common cold of mental illness"?

2.  Discuss some demographic influences on the prevalence/incidence of depression.  Explain some reasons why these influences may exist, e.g., with respect to the notion of generational cohorts.

3.  Discuss affective, cognitive, behavioral, and somatic symptoms of depression.

4.  Be able to make diagnoses of specific affective disorders using case study material as a basis.

5.  Summarize the biochemical and the cognitive theories of depression.

6.  What is meant by the positive psychology movement?  What implications does it have for the study of depression?

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