Understanding Major Depressive Disorder, Bipolar Disorders, and Schizophrenia

Major Depressive Disorder

Absence of happiness is a more reliable symptom than increases of sadness (response to happy vs. sad faces; aleatory screening of mood during the day). Depression is more frequent in women than in men (around 2:1 ratio). Symptoms: Absence of happiness, Sadness, Helplessness, Lack of energy, Feel worthless, Sleep problems. Nongenetic Biological Influences on Depression (Dp)

• Few cases of Dp are linked to viral infections e.g., Borna disease (farm animals)
• Postpartum Depression: 20% of women after birth. Majority of women recover fast.
• Hormone level changes (e.g., decrease in estrogen or progesterone) can induce depression in women with vulnerability.

Abnormalities of Hemispheric Dominance

Happy mood: increase activity in L Prefrontal Cortex. Depression: decrease activity in L Prefrontal Cortex and increase activity in R Prefrontal Cortex. Antidepressant drugs

• Tricyclic antidepressants (TCA) block the transporter protein that reabsorbs serotonin, dopamine, and norepinephrine neurotransmitters, also block histamine, acetylcholine, & sodium channels. Example: Tofranil.
• SSRI's (Selective Serotonin Reuptake Inhibitors) block the transporter protein that reabsorbs serotonin. Less pronounced side effects. Example: Prozac, Zoloft.
• Monoamine oxidase inhibitors (MAOI's) inhibit presynaptic enzyme MAO. Enzyme MAO metabolizes catecholamine and serotonin into inactive forms. MAOI effects are increasing levels of catecholamines and serotonin. Example: Nardil. Atypical antidepressants: This is a miscellaneous group that includes the rest of the drugs. Example: Bupropion. Other treatments for depression: Electroconvulsive Therapy (ECT), Hormone Leptin, Moderate exercise (e.g., walking).

Bipolar disorders: genetics aspects

• Studies have reported 2 genes that are related to a higher probability of bipolar disorder II. Treatment for Bipolar disorders
• Antidepressant drugs are not adequate for Bipolar disorders.
• Lithium salts - the most common treatment.
• Other treatments: Valproate, Carbamazepine

Schizophrenia

Deteriorating ability to function in everyday life. Hallucinations, Delusions, Thought disorders, Movement disorders, Inappropriate emotional expression. Treatment Antipsychotic drugs: Chlorpromazine Positive Symptoms Behaviors that are present but should be absent:

• Bizarre delusions
• Incoherent speech
• Inappropriate/disorganized behaviors
• Hallucinations

Negative Symptoms Behaviors that are absent but should be present. Cognitive, emotional, and behavioral deficits:

• Loss of Motivation
• Emotional Flatness
• Social Withdrawal

New drugs: Second-generation antipsychotics. Lower side effects like tremors and involuntary movements (tardive dyskinesia) compared to more typical. Are more effective treating negative symptoms. Are more widely used. However, they disrupt the immune system and have negative effects on the quality of life.

• Second-generation antipsychotics: Less effects on D2 receptors.
• Stronger antagonism on Serotonin type 2 receptors.
• Also increases the release of glutamate.