PSYC 132: Chapter 13

Affective Disorders

Affective disorders

Mental disorders characterized by dramatic changes or extremes of mood

• Hormones affect thresholds for when a stimulus elicits a particular behavior or mood

Depression

Symptoms of depression can include:

• Sadness

• Feelings of worthlessness

• Fatigue

• Guilt

• Indecisiveness

• Disturbances in sleep and food intake

• Absence of pleasure

• Suicidal thoughts

Classification

• Depression for more than 2 weeks diagnosed as

  • Major depressive disorder

• Less severe symptoms that at least 2 years is

  • Dysthymia

Hormones and Depression

Thyroid hormones

• Depression is correlated with low thyroid hormones

• In some cases, it helps to administer thyroid-releasing hormone (TRH) → thyroid-stimulating hormone (TSH) → hormone production by the thyroid gland

• Age is associated with declining thyroid function in many people

• Extent that depression is caused by decreasing thyroid function with aging is unclear

Growth hormone and Prolactin

• Correlation studies linking GH and prolactin are contradictory

Cortisol

• Negative feedback system of the HPA axis appears to be impaired in some depressed individuals

• Excessive cortisol found in about 50% of depressed individuals

  • Not seem to be related to stress because cortisol highest 3-4 hrs after sleep onset, when stress should be the lowest

• Cushing syndrome → adrenal glands that produce excessive cortisol → depression is often a symptom

• Addison disease → adrenal glands that produce insufficient cortisol → depression is often a symptom

• Nonhuman animal studies are limited help as mood must be inferred

Estrogens

• Deficits in estrogens linked with depression

• However, there are many negative side effects associated with estrogen therapy

• Sex differences in mood disorders begin at puberty; women are approximately twice as likely to develop a mood disorders

Fig. 13.2: HPA axis and depression

Blood cortisol concentrations are often higher in depressed than in nondepressed individuals

Fig. 13.4: Cortisol and mood

Optimal mood ratings correspond with moderate blood cortisol concentrations

Fig. 13.6: Estradiol withdrawal precipitation of depressive symptoms

When estradiol is withdrawn from women with a history of past depression, depression ensued

Postpartum depression (PPD)

Outcome of typical hormone changes associated with childbirth

• Confusion about its definition and if it’s a unique disorder

• Past PPD is the best predictor of future PPD

• More likely among women bringing an unwanted pregnancy to term

  • Men are nearly as likely as women (68% : 82%) to have PPD symptoms within 2 months of childbirth

Perimenstrual Syndrome

(‘peri’ → ‘around the time’) A constellation of symptoms that recurs on a cyclical basis and is associated with menstruation

• Symptoms:

  • Anxiety

  • Depression

  • Moodiness

  • Fatigue

• Associated with the normal changes in steroid hormone levels during menstruation cycle

• Most mood changes occur during late luteal phase when progesterone is peaking and estrogen is decreasing

  • No consistent differences in progesterone or estrogen have been found between women who do and do not report PMS

• No endocrine or other biological disorder has been consistently related to PMS

• PMS may be a consequence of modern civilization — of chronic cyclic hormonal functions

  • A typical women with have nearly 300 cycles by her mid thirties, with another 100-150 before menopause

• Cognitive features

  • Some women report positive mood changes and improved cognitive performance

  • 5-15% of women report elevated energy levels and well-being

  • Some report increase in sexual interest

Fig. 13.8: Optimal human interbirth interval

The optimal birth spacing is about 50 months

Seasonal Affective Disorder (SAD) AKA winter depression

Seasonal changes in behavior in many human and nonhuman animals

• Three features atypical of depression

  • Hyperphagia (abnormally high hunger)

  • Carbohydrate cravings

  • Hypersomnia (excessive sleepiness)

• Prevalence is 1%-10% with higher rates at higher latitudes

• More common in women than men (3.5 to 1)

Melatonin

Concentrations are higher during the night than during the day in both nocturnal and diurnal animals

• Converted from serotonin in the pineal gland

• Bright lights have been used to alleviate SAD presumably by resetting biological clocks by affecting timing of melatonin release

Fig. 13.14: Phase responses to melatonin

• Phase advance

  • Light exposure scheduled in the morning and melatonin given in the afternoon

• Phase delay

  • Light exposure scheduled in the evening and melatonin given in the morning

Fig. 13.15 Outdoor light is far brighter than artificial light

• Artificial light is often around 200-500 lux

  • Below what is necessary to have a physiological effect on rhythms and mood

• Sunlight may be 100,000 lux in intensity

  • Even on cloudy days → 10,000 lux

• At least 1500 lux is necessary for the inhibition of human melatonin secretion

Complete blindness

About half of the 200,000 completely blind people in the US are free-running

• 24.2-24.9 hr periods

• Often experience insomnia during the night and somnolence (drowsiness) during the day

Androgens and Affective Disorders

• More than a quarter high school seniors are currently estimated to using anabolic steroids

• Research on rodents has demonstrated that androgens have rewarding properties

  • e.g. Syrian hamsters prefer an aqueous solution with testosterone over plain water

• Gynecomastia (breast enlargement in males)

  • Peripheral conversion of androgens to estrogens

Fig. 13.17: Lifetime use of anabolic steroids

• Decreased among 10th graders in 2005

• Perceived risk of harm among HS seniors has increased

• Contrasts with previous years that showed increased usage (see image)

Steroid use

Adverse effects

• Immune dysfunction

• Liver dysfunction

• Kidney dysfunction

• Cardiovascular dysfunction

• Endocrine dysfunction

• Depression has been observed in those who stop steroid use

• Acute myocardial infarction (heart attack) and suicide are the most common causes of premature death among steroid abusers

Anorexia Nervosa

Serious, potentially life-threatening. Characterized by self-starvation and excessive weight loss

Bulimia Nervosa

Serious, potentially life-threatening. Characterized by cycles of binge eating and compensatory behaviors (e.g. self-induced vomiting)

• Typically have normal or slightly above average body mass

Commonalities between Anorexia and Bulimia

• Disordered food intake

• Distorted body image

• Compulsive exercise

• Purging behavior

• Strong genetic component

• More common in Western societies

• Almost 10x more common in women than in men

• Possibly organized by lack of prenatal androgens and activated by pubertal hormones

Hormones and Eating Disorders

Leptin (Decreases appetite)

• Anorexia

  • Very low in anorexic patients

  • Leptin treatment does not reverse low body mass

Androgens

• Females of opposite-sex twins are exposed to more prenatal androgens than females of same-sex twins

• Highest to lowest rates of disordered eating: (least to most prenatal androgens)

  • Females of same-sex twins

  • Females of opposite-sex twins

  • Males of opposite-sex twins

  • Males of same-sex twins

Emotional and binge eating peak during mid-luteal phase

• Progesterone is highest and estrogens are relatively high