3-17 Mood Disorders

Front 1

Objective

Identify two genes related to depression.

Back 1

Although the predisposition to depression undoubtedly depends on many genes, several have been identified. A particular form of one gene leads to an 80% decrease in the brain’s ability to produce the neurotransmitter serotonin. A study found this gene in nine of 87 people with major depression, and in only three of 219 people in a control group. Furthermore, two of those three had “mild depression.” Although it is clear that most people with depression do not have this gene, people who do have it are at high risk for depression.

Another gene of interest is the one controlling the serotonin transporter protein. This protein controls the ability of an axon to reabsorb serotonin after its release and recycle it for subsequent use.

Front 2

Objective

Describe the brain characteristics of depressed people.

Back 2

Most depressed people have decreased activity in the left prefrontal cortex and increased activity in the right prefrontal cortex. Many people become seriously depressed after left-hemisphere damage; fewer do after right hemisphere damage.

Front 3

Objective

List the four major categories of antidepressants.

Back 3

1. The tricyclics operate by preventing the presynaptic neuron from reabsorbing serotonin, dopamine, or norepinephrine after releasing them; thus, these neurotransmitters remain longer in the synaptic cleft and continue stimulating the postsynaptic cell.

2. The selective serotonin reuptake inhibitors (SSRIs) are similar to tricyclics but specific to the neurotransmitter serotonin. For example, fluoxetine (Prozac) blocks the reuptake of serotonin.

3. The monoamine oxidase inhibitors (MAOIs) block the enzyme monoamine oxidase (MAO), a presynaptic terminal enzyme that breaks down catecholamines (e.g. dopamine and norepinephrine) as well as serotonin into inactive forms. When MAOIs block this enzyme, the presynaptic terminal has more of neurotransmitters available for release.

4. The atypical antidepressants are a miscellaneous group of drugs (e.g. Wellbutrin) with antidepressant effects and relatively mild side effects.

Front 4

Objective

Compare the effectiveness of antidepressants, placebo, and psychotherapy.

Back 4

Antidepressant drugs help many but not all people. About 50% to 60% of all patients with depression who take antidepressants show significant improvement within a few months. Although the various antidepressant drugs differ in their side effects, they differ little in the percentage of people they help. Furthermore, about 30% of patients taking a placeb also improve within the same time frame, suggesting that many of the depressed people who improve while taking drugs would have improved without them.

An alternative to antidepressant drugs is cognitive-behavioral therapy or other forms of psychotherapy. PET scans show that both antidepressant drugs and psychotherapy increase metabolism in the same brain areas. Like antidepressant drugs, psychotherapy benefits 50% to 60% of all patients within a few months. And even a program of regular, non-strenuous exercise relieves many cases of mild depression.

Evidently, about 30% of people with depression improve without any treatment, another 20% to 30% respond well to treatment, and the rest are more challenging. Antidepressants have the advantages of being inexpensive and convenient; they also show benefits within two to three weeks, whereas the benefits of psychotherapy generally develop over months. However, psychotherapy has more enduring benefits. According to one report, 76% of patients who recover by taking drugs will relapse into depression within the first year, as opposed to 31% of those who recover through psychotherapy.

Front 5

Objective

Indicate the conditions in which ECT is most likely to be used.

Back 5

Electroconvulsive therapy (ECT) is used only for patients who have not responded to antidepressants and who have strong suicidal tendencies.

Front 6

Objective

Discuss the side effects of ECT.

Back 6

The most common side effect of ECT is memory loss, but if physicians limit the shock to the right hemisphere, the antidepressant effects occur without memory impairment. Besides the threat of memory loss, the other serious drawback to ECT is the high risk of relapsing into another episode of depression within a few months.

Front 7

Objective

Describe the altered sleep patterns of depressed people.

Back 7

Most people with depression have sleep patterns resembling those of healthy people who have gone to bed later than usual: They fall asleep but awaken early, unable to get back to sleep. They also enter REM sleep within 45 minutes after going to sleep. In addition, people who are depressed have more than the average number of eye movements per minute during REM sleep.

Front 8

Objective

Distinguish between bipolar I and bipolar II disorders.

Back 8

Depression can be either unipolar or bipolar. People with unipolar disorder vary between normality and one pole: depression. People with bipolar disorder alternate between two poles: depression and mania. Mania is characterized by restless activity, excitement, laughter, self-confidence, rambling speech, and loss of inhibitions.

People who have full-blown episodes of mania are said to have bipolar I disorder. People with bipolar II disorder have much milder manic phases, called hypomania, which are characterized mostly by agitation or anxiety.

Front 9

Objective

Compare the three drugs used in the treatment of bipolar disorder.

Back 9

The first successful treatment for bipolar disorder and the most common one is lithium, which stabilizes mood and prevents a relapse into either mania or depression. Two other effective drugs are valproate and carbamazepine. These two drugs are often recommended for patient with bipolar II disorder, characterized by mild manic phases. Lithium appears to be more effective for people with bipolar I disorder.

Front 10

Objective

Describe the symptoms and treatment of SAD.

Back 10

Seasonal affective disorder (SAD) is a form of depression that recurs during winter months. SAD is most prevalent near the poles, where the winter nights are long; is less common in moderate climates; and is unheard of in the tropics. Most people feel happier and more active during the summer, when there are many hours of sunlight, than during winter.

SAD differs from other types of depression in many ways; for example, patients with SAD have phase-delayed sleep and temperature rhythms, becoming sleepy and wakeful a bit later than normal. This distinguishes them from most patients with depression, whose rhythms are phase-advanced. SAD is seldom as severe as major depression. It is possible to treat SAD with very bright full-spectrum lighting for an hour or more each day. The light affects serotonin synapses and alters circadian rhythms. Bright light relieves this form of depression at least as well as drugs or psychotherapy.

Front 11

major depression

Back 11

State of feeling sad, helpless, and lacking in energy and pleasure for weeks at a time

Front 12

postpartum depression

Back 12

Depression after giving birth

Front 13

tricyclics

Back 13

Drugs that prevent the presynaptic neuron that releases serotonin or catecholamine molecules from reabsorbing them

Front 14

selective serotonin reuptake inhibitors (SSRIs)

Back 14

Drugs that block the reuptake of serotonin into the presynaptic terminal

Front 15

monoamine oxidase inhibitors (MAOIs)

Back 15

Drugs that block the enzyme monoamine oxidase (MAO), a presynaptic terminal enzyme that metabolizes catecholamines and serotonin into inactive forms

Front 16

atypical antidepressants

Back 16

Miscellaneous group of drugs with antidepressant effects but only mild side effects

Front 17

electroconvulsive therapy (ECT)

Back 17

Electrically inducing a convulsion in an attempt to relieve depression or other disorder

Front 18

unipolar disorder

Back 18

Mood disorder with only one extreme (or pole) generally depression

Front 19

bipolar disorder

Back 19

Condition in which a person alternates between the two poles of mania and depression

Front 20

bipolar I disorder

Back 20

Condition including full-blown episodes of mania

Front 21

bipolar II disorder

Back 21

Condition with only mild manic phases, characterized by agitation or anxiety

Front 22

seasonal affective disorder (SAD)

Back 22

Period of depression that recurs seasonally, such as in winter