Mood Disorders

Lesson 24

Mood Disorders

Unipolar depression Mania Bipolar disorder Seasonal Affective Disorder (SAD) ~

Unipolar Depression

Extreme sadness & despair extent & duration important

Prevalence females 9-26% males 5-12% 2:1 females ~

Unipolar Depression

endogenous vs. reactive Genetic component

DZ twins 25% concordance MZ twins 70% concordance

Diagnosis & Symptoms

Disrupted eating & sleeping increased or decreased

Impaired concentration Changes in activity

increased or decreased Feelings of guilt / worthlessness Preoccupation w/ death or suicide ~

NOT uncomplicated bereavement organic

Diagnosis 5 of 9 symptoms

not complete list duration > 2 weeks ~

Diagnosis & Symptoms

Treatment

Psychotherapy Drug Therapy Electroconvulsive-shock Therapy Sleep Deprivation Light Therapy ~

Etiology

Catecholamine hypothesis DA & NE deficiency

Evidence from drug side effects Produce depression reserpine – monoamines propranalol - NE antagonist ~

Monoamine Hypothesis

Fluoxetine (Prozac) therapeutic effects blocks 5-HT reuptake

5-HT modulates other NTs? usually more than one NT involved ~

Drug Treatment

Monoamine oxidase inhibitors – MAOIs NT not degraded more NT in synapse

Cheese effect foods with tyramine metabolism amphetamine-like risk of cerebral hemorrhage ~

Tricyclic Antidepressants

Indirect agonists block monoamine reuptake imipramine, desipramine

Side effects Sympathetic arousal Possible overdose ~

SSRIs Selective serotonin reuptake inhibitors

Prozac (fluoxetine) Zoloft (sertraline) Paxil (paroxetine) Luvox (fluvoxamine)

blocks 5-HT reuptake Less effect on NE & DA ~

SSRIs vs Tricyclics

Fewer side effects less danger of overdose

As effective as tricyclics Neither addictive

Animals don’t self-administer negative reinforcement ~

Criticisms Immediate effects on NT level Therapeutic effects 2-4 weeks Explanation?

Compensatory responses Autoreceptor desensitization ~

Tetracyclic Antidepressants

Block reuptake & autoreceptors Faster therapeutic effects?

yes... but still a delay ~

Other Selective Reuptake Inhibitors Norepinephrine Dopamine Reuptake

Inhibitor (NDRI) bupropion (Welbutrin) Also tx bipolar & Smoking cessation

(Zyban) Side fx

less sexual dysfuntion than SSRI Insomnia seizures - 150 mg/dose limit no subjective euphoria, abuse ~

Selective Serotonin Norepinephrine Reuptake Inhibitor (SNRI) venlafaxine (Effexor)

Serotonin-2 Antagonists/Reuptake Inhibitors (SARI) Trazodone (Desyrel) 5HT2 –R: autoreceptor Anxiety disorders, bulimia

Off-label use of antidepressants wide variety of disorders ~

Other Selective Reuptake Inhibitors

Electroconvulsive Therapy - ECT

Rapid effects - few days Indications

drug therapy ineffective danger of suicide Risk of drug interactions

Mechanisms unknown ~

Sleep Deprivation

Depression Early & frequent REM Tricyclics inhibit REM

REM deprivation gradual therapeutic effects

Total sleep deprivation immediate therapeutic effects

Mechanisms unknown ~

Mania & Bipolar

Mania Symptoms Euphoria grandiose plans reduced need for sleep high risk activities

Bipolar Disorder Cycling between mania &

depression ~

Etiology

Induced by drugs Monoamine agonists cocaine, amphetamine,

antidepressants Mostly NE & DA ~

Treatment: Mania & Bipolar

Lithium most common Dangerous, but thresholds well

known Mechanism unknown

affects almost all NTs Also

Anticonvulsants atypical neuroleptics ~