Schizophrenia Lesson 26 Schizophrenia Disordered thoughts bizarre behavior

Schizophrenia Lesson 26

Schizophrenia Disordered thoughts & bizarre behavior l 1 percent of population l equal among sexes n Progressive? l can only manage symptoms n Symptoms > 6 mo l 2 classes of symptoms l Positive l Negative ~ n

Positive Symptoms n Thought disorders l l n n incoherence loose associations Delusions l bizarre beliefs l persecution, grandeur Hallucinations l l sensory experiences no external stimuli ~

Negative Symptoms Poverty of speech l little spontaneous speech n Poverty of emotion l Flattened, inappropriate affect n Social withdrawal l lack of personal hygiene ~ n

Positive Symptoms n Thought disorders l l n n incoherence loose associations Delusions l bizarre beliefs l persecution, grandeur Hallucinations l l sensory experiences no external stimuli ~

Negative Symptoms Poverty of speech l little spontaneous speech n Poverty of emotion l Flattened, inappropriate affect n Social withdrawal l lack of personal hygiene ~ n

Anatomical Indicators Increased ventricle size l 67% of cases n brain atrophy l HC l thalamus (Nancy S Andresen, UI) l general atrophy ~ n S N

Heritability General Population 1% l One parent schiz. 17% l DZ twins 17% l MZ twins 50% n Strong genetic component l predisposition + stressor n Adoption Studies l risks more like biological parents n Evidence of gene(s) elusive ~ n

The Dopamine Hypothesis Positive symptoms l too much DA activity l Not excessive DA levels l Maybe overabundance of receptors n 2 major DA systems l Mesolimbic l Nigrostriatal ~ n

Major DA Pathways Striatum Nucleus Accumbens Mesolimbic pathway Ventral Tegmental Area Nigrostriatal pathway VTA SN Substantia Nigra

DA Hypothesis: Evidence Therapeutic Drugs l Neuroleptics (Antipsychotics) l DA antagonists n DA agonists l amphetamines, cocaine, etc. l induce symptoms n Problem: delay in effects ~ n

1 st Generation Neuroleptics Relieve only positive symptoms n Chlorpromazine (Thorazine) l phenothiazines l primarily blocks D 1 & D 2 n Haloperidol (Haldol) l butyrophenones l primarily blocks D 2 n D 2 -R affinity and clinical potency ~ n

Hi Therapeutic effects Lo Spiroperidol Haloperidol Chlorpromazine Strength of D 2 binding

1 st Generation: Side Effects Motor l Nigrostriatal pathway l Tardive Dyskinesia l Parkinson-like symptoms n Sedation l low compliance ~ n

2 nd Generation Neuroleptics Block DA and 5 -HT receptors l Relieve positive & negative symptoms l Lower Parkinson’s-like side effects n Clozapine (Clozaril) l high risk agranulocytosis n Risperidone (Risperidal) l low risk of agranulocytosis ~ n