Introduction to Psychiatry Sir Christian Kreipke, PhD, FRSC Introduction to Psychiatry
What is a Psychiatric Condition? A disease manifested in the brain that causes deviation in behavior from a set of socially acceptable norms Distinct from psychological conditions in that a supposed somatic pathotrajectory exists Can be induced by genetic conditions, damage to the brain, or environmental conditions
Normal Abnormal
Psychiatric Criminal
Medical Anthropological perspective Most societies have there own set of codes for “normal” and “abnormal” behavior These closely defined norms may or may not overlap Examples: ADHD does not exist in Cuba Infanticide is culturally acceptable in China Cannibalism is still practiced in certain tribes of the South Pacific region Female circumcision Tattoos Etc.
Common Psychiatric Disorders Schizophrenia (10%) Turret's Syndrome (~1:10,000) Bipolar (~1:5,000) ADHD (~15-20%) Autism (~15%) Depression (~20%) Obsessive Compulsive disorder (~5%)
Schizophrenia Characterized by a whole host of conditions According to the DSM-IV, if the subject exhibits 2 or more of the following they have a probability of schizophrenia: Auditory/visual hallucinations Asocial behavior Aggressive behaviors Confusion Negative affect “split personality disorder”
Schizophrenia Possible biological cause Abnormal development in striatum, medial temporal lobe, and/or corpus collosum Hyperdopaminergic and hypoglutamatergic drive to the striatum More generally, disrupted dopaminergic system
Schizophrenia Treatment: Haldol (D2 antagonist) Clorpromazine/clozapine (atypical antipsychotic which binds D3/4 system) PROBLEM: Patient’s behavior can be severely altered
Bipolar Characterized by multiple personality types (2 or more) and/or by severe shifts in mood (manic-depression)
Bipolar Possible biological cause: Abnormal development of striatum, corpus collosum, and/or prefrontal cortex Disrupted glutamatergic drive to the cortex
Bipolar Treatment: Lithium (mood stabilizer) Mode of action? UNKNOWN
ADHD Characterized by lack of ability to focus on single task and/or hyperactivity associated with lack of focus
ADHD Possible biological causes: Dysfunctional dopaminergic system particularly in the striatum
ADHD Treatment: Dopaminergic drugs (amphetamine derivatives, psychostimulants) How do they work? Deplete the dopamine system quickly. Recovery time squelches dopamine drive and quiets overactive behaviors. Specifically they cause dopaminergic neurons to release dopamine and block reuptake via blocking the DAT
Depression Characterized by chronic negative affect usually not correlated with a particular event. CAVEAT: clinical depression may be triggered by environmental cue. Emphasis on chronic!!!
Depression Possible biological cause: Disrupted serotonergic drive to cortex
Depression Treatment: SSRIs. Selectively prevent serotonin reuptake through the serotonin transporter, thus allowing more to remain in the synaptic cleft.
OCD Characterized by repetitive often self-injurous behaviors
OCD Possible biological cause Recapitulates that of depression
OCD Treatment: SSRIs most effective Cognitive behavioral therapy
Others Autism, turret’s and a host of other pathological conditions sadly have unknown biological pathotrajectories and hence treatment is often laborious and inconclusive