Mood Disorders Lesson 25 Mood Disorders Unipolar depression

Mood Disorders Lesson 25

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

Unipolar Depression Extreme sadness & despair l extent & duration important n Prevalence l females 9 -26% l males 5 -12% n l 2: 1 females ~

Unipolar Depression endogenous vs. reactive n Genetic component l DZ twins 25% concordance l MZ twins 70% concordance n

Diagnosis & Symptoms Disrupted eating & sleeping l increased or decreased n Impaired concentration n Changes in activity l increased or decreased n Feelings of guilt / worthlessness n Preoccupation w/ death or suicide ~ n

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

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

Etiology Catecholamine hypothesis l DA & NE l deficiency n Evidence from drug side effects l Produce depression l reserpine – monoamines l propranalol - NE antagonist ~ n

Monoamine Hypothesis Fluoxetine (Prozac) l therapeutic effects l blocks 5 -HT reuptake n 5 -HT modulates other NTs? l usually more than one NT involved ~ n

Drug Treatment Monoamine oxidase inhibitors – MAOIs l NT not degraded l more NT in synapse n Cheese effect l foods with tyramine l metabolism amphetamine-like l risk of cerebral hemorrhage ~ n

Tricyclic Antidepressants Indirect agonists l block monoamine reuptake l imipramine, desipramine n Side effects l Sympathetic arousal l Possible overdose ~ n

SSRIs n Selective serotonin reuptake inhibitors l Prozac (fluoxetine) l l l n Zoloft (sertraline) Paxil (paroxetine) Luvox (fluvoxamine) blocks 5 -HT reuptake l Less effect on NE & DA ~

SSRIs vs Tricyclics Fewer side effects l less danger of overdose n As effective as tricyclics n Neither addictive l Animals don’t self-administer l negative reinforcement ~ n

Criticisms Immediate effects on NT level n Therapeutic effects 2 -4 weeks n Explanation? l Compensatory responses l Autoreceptor desensitization n Tetracyclic Antidepressants l Block reuptake & autoreceptors l Faster therapeutic effects l but still a delay ~ n

Other Selective Reuptake Inhibitors Norepinephrine Dopamine Reuptake Inhibitor (NDRI) l bupropion (Welbutrin) l Also tx bipolar & Smoking cessation (Zyban) n Selective Serotonin Norepinephrine Reuptake Inhibitor (SNRI) n Serotonin-2 Antagonists/Reuptake Inhibitors (SARI) n Off-label use of antidepressants l wide variety of disorders ~ n

Mania & Bipolar Mania Symptoms l Euphoria l grandiose plans l reduced need for sleep l high risk activities n Bipolar Disorder l Cycling between mania & depression ~ n

Etiology n Induced by drugs l Monoamine agonists l cocaine, amphetamine, antidepressants l Mostly NE & DA ~

Treatment: Mania & Bipolar Lithium most common l Dangerous, but thresholds well known n Mechanism unknown l affects almost all NTs n Also l Anticonvulsants l atypical neuroleptics ~ n