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Chapter 15 Psychological Disorders Substance Abuse and Addictions • Mental illness Substance Abuse and Addictions • Substance abuse Substance Abuse and Addictions • Olds and Milner (1954) Fig. 15-1, p. 452 Substance Abuse and Addictions • Other behaviors that release dopamine Substance Abuse and Addictions • Berridge and Robinson (1998) – Nucleus accombans Substance Abuse and Addictions • Addiction Substance Abuse and Addictions • Withdrawal Substance Abuse and Addictions • Alcohol Substance Abuse and Addictions • The genetic basis for early-onset alcoholism is stronger than for later-onset, especially in men. • Researchers distinguish between two types of alcoholism 1. Type I/Type A 2. Type II/Type B Substance Abuse and Addictions • Type I/Type A characteristics Substance Abuse and Addictions • Type II/Type B characteristic Substance Abuse and Addictions • Twin studies and family studies suggest a genetic basis for Type II/Type B alcoholism. Substance Abuse and Addictions • Risk factors for alcoholism Substance Abuse and Addictions • Medications used to combat alcoholism Mood Disorders • Major depression - feeling sad and helpless everyday for weeks at a time Mood Disorders • Similar symptoms can result from hormonal problems, head injuries, brain tumors, or other illnesses. • Often comorbid with other disorders Mood Disorders • Studies of twins and adopted children suggest a moderate degree of heritability. Mood Disorders • Predisposition depends on a variety of genes. • One identified gene leads to an 80% decrease in the brain’s ability to produce serotonin. – Most depressed people do not have this gene. – Those who have the gene have a higher predisposition. Mood Disorders • Another gene identified controls the serotonin transporter protein. – Protein controls the ability of the axon to reabsorb the neurotransmitter after its release. • Two “short forms” of the gene are associated with an increased likelihood of depression after stressful events. – Perhaps alters the way people react to stressful events. Mood Disorders • Specific hormones are also involved with depression. Mood Disorders • Postpartum depression Mood Disorders • Childhood depression is equally common in both boys and girls. • After puberty, depression is twice as common in females. • The finding is consistent across cultures, suggesting a biological factor. Mood Disorders • Depression is associated with the specific brain activity Mood Disorders • Some cases of depression may be linked to viral infection. – Borna disease Mood Disorders • Categories of antidepressant drugs include: 1. Tricyclics. 2. Selective serotonin reuptake inhibitors. 3. MAOI’s. 4. Atypical antidepressants. Fig. 15-9, p. 463 Mood Disorders • Tricylclics (imipramine -Tofranil) Mood Disorders • Selective serotonin reuptake inhibitors (SSRIs) – • Examples: Fluoxetine (Prozac), setraline (Zoloft), fluvoxamine (Luvox), citalopram (Celexa) and paroxetine (Paxil). Mood Disorders • Monoamine oxidase inhibitors (MAOI’s) Mood Disorders • Atypical antidepressants - Example: bupropion (Wellbutrin) Mood Disorders • Exactly how antidepressant drugs work is unclear. Mood Disorders • In some depressed people, neurons in the hippocampus and the cerebral cortex shrink. Mood Disorders • Electroconvulsive therapy (ECT) Mood Disorders • Drawbacks Mood Disorders • “Receptive transcranial magnetic stimulation” Mood Disorders 1. Unipolar disorder 2. Bipolar disorder (manic-depressive disorder) Mood Disorders • Bipolar disorder I – • Bipolar disorder II - Mood Disorders • Research suggests a heritability basis for bipolar disorder (Craddock & Jones, 1999). Mood Disorders • Treatments for bipolar – brain chemical arachidonic acid. Schizophrenia • Schizophrenia Schizophrenia • Causes are not well understood but include a large biological component. Schizophrenia • Two cluster of positive symptoms of schizophrenia include: 1. Psychotic 2. Disorganized Schizophrenia 1. Psychotic - consists of delusions and hallucinations. – Delusions – Hallucinations 2. Disorganized Schizophrenia • Negative symptoms Schizophrenia • Twin studies suggest a genetic component. Schizophrenia • Prenatal environment Schizophrenia • One study identified a gene linked to high levels of negative symptoms (Fanous et al., 2005). Schizophrenia • The neurodevelopmental hypothesis Schizophrenia • Supporting evidence for the neurodevelopmental hypothesis Schizophrenia • Prenatal risk factors increasing the likelihood of schizophrenia include: – Poor nutrition of the mother during pregnancy. – Premature birth. – Low birth weight. – Complications during delivery. • Head injuries in early childhood are also linked to increased incidence of schizophrenia. Schizophrenia • Schizophrenia is associated with mild brain abnormalities Schizophrenia • Schizophrenia typically develops after the age of 20 but many show sign at an earlier age. Fig. 15-17, p. 476 Schizophrenia • Antipsychotic/neuroleptic drugs • Chlorpromazine Schizophrenia • Two chemical families of drugs used to treat schizophrenia include: 1. Phenothiazines - includes chlorpromazine 2. Butyrophenones - includes halperidol (Haldol) • Both drugs block dopamine synapses. Schizophrenia • Second-generation antipsychotics Schizophrenia • The dopamine hypothesis of schizophrenia – Substance-induced psychotic disorder Schizophrenia • Research indicates increased activity specifically at the D2 receptor. • Limitations of the dopamine hypothesis Schizophrenia • The glutamate hypothesis of schizophrenia Schizophrenia • Schizophrenia cannot be explained by a single gene or single transmitter. • Dopamine and glutamate may play important roles in schizophrenia to different degrees in different people. • Schizophrenia involves multiple genes and abnormalities in dopamine, glutamate, serotonin and GABA.