Ch. 13: Psychological Disorders

Schizophrenia

• breakdown in thinking and poor emotional response

• prevalence = 1.1%

• equally split between genders

pos, neg, cog symptoms of Schizophrenia

pos = added behavior

neg = behavior not present in patient, but is present in healthy pop.

cog = executive func. deficit

genetic/environmental causes of Schizophrenia

Genetic:

• DISC 1: disrupted in Schizophrenia on chromosome 1

Environmental:

• place/time of birth

• infection of mother during pregnancy

• stress from mom during preg.

• birth problems

brain structures affected in Schizophrenia

• enlarged ventricles = loss of neurons in adjacent areas

• disorganization of cells in hippocampus

• reduced activity of frontal cortex

• loss of gray matter (too much synaptic pruning) in adolescent

biochemistry of schizophrenia

• too much dopamine (positive symptoms)

• reduced activity of NMDA (glutamate receptors)

treatment of schizophrenia

typical antipsychotics: dopamine antagonist

• binds to dopamine receptor → dopa cannot bind → no effect on post synap.

• reduces pos symptoms

atypical antipsychotics: serotonin agonist; ACh receptor agonist

• improve negative symptoms

Schizophrenia symptoms table

Major Depressive Disorder (MDD) symptoms

• insomnia/hypersomnia

• restlessness or feeling slowed down

• significant weight lost or gain

genetic causes of MDD

• serotonin transporter allele:

  • short: less transporter on pre-synap. → more serotonin in cleft → keeps activating post-synap. → incr risk of MDD

  • long: more transporter → efficient in taking serotonin → less serotonin in cleft

• overactivation of amygdala

environmental causes of MDD

• stress

  • HPA axis: stress → pituitary → adrenal gland → cortisol → negative feedback → deactivate hypothalamus

brain structures affected in MDD

• decreased volume of hippocampus (less neurogenesis)

• decreased activity of ACC

• increased activity of amygdala

• abnormal communication between frontal cortex and limbic system

biochemistry of MDD

• norepinephrine = alertness and energy

• serotonin = anxiety, obsessions, compulsions

• dopamine = attention, motivation, pleasure, reward, interest in life

treatment of MDD

• SSRI: boost serotonin by blocking transporter

• brain stimulation:

symptoms of bipolar disorder (BD)

• fluctuations in mood

• distinct period of irritable mood

• excessive energy

• excessive involvement in pleasure seeking activities

brain structures affected in BD

• reduced hippocampal volume

• elevated basal ganglia activity (manic phase)

• increased amygdala volume and activation

• overall increased activity in brain

biochemistry of BD

• norepinephrine: incr alertness & energy (manic phase)

• serotonin: decreased emotional regulation (depressive phase)

treatment for BD

mood stabilizers

anxiety disorders

excessive and persistent feeling of fear or worry that interferes w/everyday life

OCD

• obsession = intrusive thoughts producing uneasiness, fear, or worry

• compulsion = repetitive behaviors aimed to reduce associated anxiety

neural network affected in OCD

hyperactive cortico-striatal-thalamo-cortical loop (controls movement execution, habit formation, and reward)

PTSD

recurrent dreams, flashbacks, hyperarousal, and avoidance stimuli associated w/trauma, high lvls of vigilance, and an impairment in daily func.

brain structures affected in PTSD

• shrinkage of hippocampus

  • smaller hypothalamus → less glucocorticoid receptor → less efficient at negative feedback of hippocampus → more stress

• over-activation of amygdala

• decreased activation on prefrontal cortex

Autism Spectrum Disorder

• varying degrees of difficulties in social interaction, nonverbal communication, and repetitive behavior

• more prominent in men

causes of ASD

many genetic and environmental factors

brain regions affected in ASD

• excessive brain growth due to lack of synaptic pruning

• smaller corpus callosum: comm. btwn hemispheres

• amygdala: emotion and social behavior (abnormal func.)

• cerebellum: motor activity balance, coordination (repetitive movement)

biochemistry of ASD

• glutamate-GABA imbalance

• low lvls of serotonin in brain; high lvls in blood

ADHD

• significant problems of attention, hyperactivity, and/or acting impulsively that are not appropriate for one’s age

• more boys diagnosed than girls

causes of ADHD

• high genetic component

• environmental factors

  • brain injurt

  • low birth weight

  • exposure to toxic environment

  • substance-use during pregnancy

  • premature delivery

brain regions involved with ADHD

• reduced activity of prefrontal cortex

• smaller basal ganglia = hyperactivity

biochemistry of ADHD

dopamine lvls reduced

treatment of ADHD

dopamine reuptake inhibitor = block reuptake transporter to boost dopamine