16- Biopsychology of Psychiatric Disorders

Psychiatric disorders

disorders of psychological function sufficiently severe to require treatment

DSM-5 (Diagnostic and Statistical Manual)

Diagnosis is guided by

Schizophrenia

means the splitting of psychic functions

Schizophrenia

The term was coined in the early years of the 20th century to describe what was assumed at the time to be the primary symptom of the disorder: the breakdown of integration

among emotion, thought, and action.

schizophrenia spectrum disorders

Because the current

definition of schizophrenia overlaps

with that of several different disorders, the DSM­5 prefers

to use the label - to refer to

schizophrenia and related disorders

Positive symptoms

symptoms that seem to

represent an excess of typical function

Negative symptom

symptoms that seem to represent a

reduction or loss of typical function

Hallucination

Imaginary voices making critical comments

or telling patients what to do

Inappropriate affect

Failure to react with the appropriate

emotion to positive or negative events.

Disorganized speech or thought

Illogical thinking, peculiar

associations among ideas, belief in supernatural forces

Odd behavior

Difficulty performing everyday tasks,

lack of personal hygiene, talking in rhymes

Affective flattening

diminished emotional expression

Avolition

reduction or absence of motivation

Catatonia

Remaining motionless, often in awkward

positions for long periods

delusions, hallucinations, or disorganized speech

The frequent recurrence of any two of these symptoms 0or 1 month is currently sufficient for the diagnosis

of schizophrenia—provided that one of the symptoms is -

Antipsychotic drug

a drug that is

meant to treat certain symptoms of schizophrenia

and bipolar disorders

Chlorpromazine

The first major breakthrough in the study of the biochemistry

of schizophrenia was the accidental discovery in the

early 1950s of the first antipsychotic drug called -

Psychosis

loss of touch with reality

Reserpin

the active ingredient of the snakeroot plant—given to patients with schizophrenia and confirmed its antipsychotic action

Dopamine theory of schizophrenia

the theory that schizophrenia is caused by

too much dopamine and, conversely, that antipsychotic drugs

exert their effects by decreasing dopamine levels.

Receptor blocker

chlorpromazine

is a - at dopamine synapses—that is, it binds

to dopamine receptors without activating them and, in so

Chlorpromazine

We now know that many psychoactive drugs are

receptor blockers, but - was the first to be

identified as such

Haloperidol

was one of the most potent antipsychotic

drugs of its day, it had a

relatively low affinity for dopamine

receptors.

Phenothiazines

chemical class of chloropromazine and other antipsychotic drugs that effectively bind to both D1 and D2 receptors

Butyrophenones

chemical class of haloperidol and other antipsychotic drugs that effectively bind to both D2 receptors but not to D2 receptors

Typical antipsychotics

the first generation of antipsychotic drugs

Spiroperidol

had the greatest affinity for

D2 receptors and the most potent antipsychotic effect.

Atypical antipsychotics

also known as second­ generation antipsychotics are often the drugs of choice for the treatment of schizophrenia

Atypical antipsychotics

are drugs that are effective against schizophrenia but yet do not bind strongly to D2 receptors.

Clozapine

the first atypical antipsychotic

to be approved for clinical use, has an affinity for D1 receptors, D4 receptors, and several serotonin and histamine

receptors, but only a slight affinity for D2 receptors

Psychedelic drugs

drugs whose primary action

is to alter perception, emotion, and cognition

LSD (lysergic acid diethylamide)

The study of psychedelic drugs began

in the 1950s with the discovery of -

Clinical depression/ major depressive disoder

When this depression

lasts for 2 weeks or longer, these people are said to be suffering

from a

Reactive depression

Depression triggered by an obvious negative experience

Endogenous depression

depression with no apparent cause

Cormobid

In adults, clinical depression is often -

(the tendency for two health conditions to occur together

in the same individual) with one or more other health

conditions—for example, anxiety disorders, coronary

heart disease, and diabetes

Seasonal affective disorder (SAD)

episodes of depression and lethargy typically recur

during particular seasons—usually during the winter

months.

Light therapy

exposure to 15­-30 minutes of very bright light

each morning

Peripartum disorder

the intense,

sustained depression experienced by some women

during pregnancy, after they give birth, or both

1. Monoamine oxidase inhibitors

2. Tricyclic antidepressants

3. Selective monoamine-reuptake inhibitors

4. Atypical antidepressants

5. NMDA- receptor antagonists

classes of drugs used for the treatment of depressive disorders

Iproniazid

first antidepressant drug, was originally developed for

the treatment of tuberculosis,

Monoamine oxidase (MAO)

it increases the

levels of monoamines

by inhibiting the activity of -

Tricyclic antidepressant

named because of their antidepressant

action and because their chemical structures include three

Imipramine

first tricyclic antidepressant

Selective serotonin-reuptake inhibitors (SSRIs)

are serotonin agonists that exert their agonistic

effects by blocking the reuptake of serotonin

Fluoxetine (Prozac)

was the first SSRI to be developed

Selective norepinephrine reuptake inhibitors (SNRIs)

The success of the SSRIs spawned the introduction

of a similar class of drugs,

Atypical antidepressants

a catch­all class comprising drugs that have

many different modes of action

Bupropion

It is a blocker of dopamine

and norepinephrine reuptake, and it is also a blocker of

nicotinic acetylcholine receptors

Agomelatine

melatonin receptor agonist

Ketamine

Beginning in

the early 1990s, several studies reported a positive effect

of antagonizing the glutamate NMDA receptor on

depressive disorders. In the early 2000s, one agent in

particular was shown to be remarkably effective: the

dissociative hallucinogen -

Monoamine theory of depression

holds that depression

is associated with underactivity at serotonergic and

noradrenergic synapses.

Up-regulation

When an insufficient amount of

a neurotransmitter is released at a synapse,

there is usually a compensatory

increase in the number of receptors for

that neurotransmitter—a process called

Neuroplasticity theory of depression

is that depression results from a decrease of neuroplastic processes in various brain structures which leads to neuron lossn and other neural pathology

Brain-derived neurotropic factor (BDNF)

it has been proposed that decreased

blood levels of - might be a biomarker for depression

Biomarker

a biological state that is predictive of a particular disorder

Repetitive transcranial magnetic stimulation (rTMS)

form of TMS that involves the noninvasive delivery of repetitive magnetic pulses at either high frequencies or low frequencies to specific cortical areas such as the prefrontal cortex

Bipolar disorder

Depression and periods of hypomania or mania

Hypomania

characterized by a reduced

need for sleep, high energy, and positive affect.

Hypomania

During periods of -, people

are talkative, energetic, impulsive, positive,

and very confident. In this state, they can be very effective

at certain jobs and can be great fun to be with.

Mania

symptoms such as delusions of grandeur, overconfidence,

impulsivity, and distractibility.

psychosis

loss of touch with reality

Mania

often leaves behind a trail of

unfinished projects, unpaid bills, and broken

relationships.

Bipolar disorder type II

experience

bouts of depression and hypomania

Bipolar disorder type I

experience bouts of mania

Mixed state

displaying symptoms of both

severe depression (e.g., suicidal ideation) and mania (e.g. delusions of grandeur)

Rapid cycling bipolar disorders

subtype of bipolar disorders defined as involving 4 or more mood episodes per year

Mood stabilizers

drugs that effectively treat depression

or mania without increasing the risk of mania or depression, respectively

Lithium

first drug found to act as a mood stabilizer

Anxiety

chronic fear that persists in the absence of any direct threat—is a common psychological correlate of stress

Anxiety disorders

most prevalent of all psychiatric disorders

Generalized anxiety disorder

characterized by stress responses and extreme feelings of anxiety and worry about a large number of different activities or events

Specific phobias

strong fear or anxiety about specific objects

Agoraphobia

pathological fear of public places

Panic disorder

recurrent rapid-onset attacks of extreme fear and sever symptoms of stress

Benzodiazepines

They are also prescribed as hypnotics, anticonvulsants, and muscle relaxants.

1. Chlordiazepoxide (Librium)

2. Diazepam (Valium)

common benzodiazepines

Ataxia

disruption of motor actvity

Buspirone

serotonin agonist used for anxiety disorders

Buspirone

It produces

anxiolytic (antianxiety) effects without producing

ataxia, muscle relaxation, and sedation

elevated-plus-maze test

the measure of anxiety is the proportion

of time the rats spend in the enclosed arms, rather than venturing onto the exposed arms.

defensive-burying test

The measure of anxiety

is the amount of time the rats spend spraying bedding

material from the floor of the chamber at the source of the

shock with forward thrusting movements of their head

and forepaws.

Risk assesment test

The measures of anxiety

in this test are the amounts of time that the rats spend in

freezing

Tourette’s disorder

disorder of tics

Tics

involuntary, repetitive, stereotyped movements or vocalizations

Simple motor tics

eye blinking, or head movements

Complex motor tics

hitting, touching objects, hopping, twirling, and sometimes making lewd gestures

Coprolalia

uttering obsceneties

Echolalia

repitition of another’s words

Palilalia

repitition of one’s own words

Rebound

tics become even worse following a period of suppression

Striatum (caudate plus putamen)

Most research on the cerebral pathology associated

with Tourette’s disorder has focused on the

Antipsychotics

the tics of tourette’s disorder are usually treated with -

Translational research

Research

designed to translate basic scientific discoveries into effective

clinical treatments is called

Clinical trials

studies conducted on human volunteers to assess the therapeutic efficacy of an untested drug or other treatment

Phase 1: Screening for Safety

to determine whether

the drug is safe for human use and, if it is, to determine

how much of the drug can be tolerated.

Phase 2: Establishing the testing protocol

purpose of the second phase of a clinical trial is to

establish the protocol (the conditions) under which the final

tests are likely to provide a clear result

Placebo-control groups

groups of patients who receive a control substance

rather than the drug

Double-blind

the tests are conducted so that neither the patients

nor the physicians interacting with them know which

treatment (drug or placebo) each patient has received.

Phase 3: Final testing

typically a double­blind, placebo­control study on large

numbers—often, many thousands—of patients suffering

from the target disorder