Mood Disorders Lesson 24

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

Unipolar Depression 2:1 females ~ 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 Feelings of guilt / worthlessness Preoccupation w/ death or suicide ~

Diagnosis & Symptoms NOT uncomplicated bereavement organic Diagnosis 5 of 9 symptoms not complete list duration > 2 weeks ~

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 ~

Other Selective Reuptake Inhibitors 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 ~

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 ~