ch 18 psychiatric disorders
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Ch 18 Psychiatric Disorders. Psychiatric Disorders. Disorders of psychological function sufficiently severe to require treatment Diagnosis can be difficult Patients with the same disorder can display different symptoms - PowerPoint PPT PresentationTRANSCRIPT
Ch 18 Psychiatric Disorders
Psychiatric Disorders
Disorders of psychological function sufficiently severe to require treatment
Diagnosis can be difficult Patients with the same disorder can display different
symptoms Patients with different disorders can display many of
the same symptomsDiagnosis based on info from the DSM
(Diagnostic & Statistical Manual of the American Psychiatric Association)
Psychiatric Disorders
SchizophreniaAffective Disorders: Depression & ManiaAnxiety DisordersTourette Syndrome
Schizophrenia
Means “splitting of psychic functions”The disorder most commonly associated with
madnessAffects 1% of the populationTypically begins in adolescence or early
adulthoodComplex & diverse symptoms that overlap with
those of other disordersSymptoms frequently change during
progression of the disorderNo single symptom appears in all cases
Schizophrenia
Symptoms split into 2 categories:1. Positive:
Symptoms that seem to represent an excess or distortion of normal function
2. Negative: Symptoms that seem to represent a reduction or
loss of normal function
Positive Symptoms of Schizophrenia
Delusions Delusions of being controlled, persecution, or grandeur
Hallucinations Imaginary voices making critical comments or telling the
individual what to doInappropriate affect
Failure to react with the appropriate emotion to eventsIncoherent speech or thought
Illogical thinking, echolalia (vocalized repetition of some or all of what was heard), peculiar associations among ideas, belief in supernatural forces
Odd behavior Difficulty performing everyday tasks, lack of personal hygiene,
talking in rhymes, catatonia (remaining motionless, often in awkward positions)
Negative Symptoms of Schizophrenia
Affective flattening Reduction or absence of emotional expression
Alogia Reduction of absence of speech
Avolition Reduction or absence of motivation
Anhedonia Inability to experience pleasure
Causal Factors in Schizophrenia
Genetic componentBut experience also plays a roleSome people inherit a potential for the
disorder & it may or may not be activated based on experience
Factors that can contribute to the development of schizophrenia Birth complications, early infections, autoimmune
reactions, toxins, traumatic injury & stress
Dopamine Theory of Schizophrenia
First suggested by the fact that early antipsychotic drugs (chlopromazine & reserpine) caused motor effects like those of Parkinson’s
Theory that schizophrenia is caused by the presence of too much dopamine
Amphetamine & cocaine, which increase dopamine, can cause schizophrenic episodes in healthy people
Dopamine Theory of Schizophrenia
Discovery that there are 5 subtypes of dopamine receptors (D1-D5)
Drugs worked in different ways because they acted on different receptor subtypes
Schizophrenia is caused by hyperactivity specifically at D2 receptors Widely accepted, but still doesn’t explain the whole
pictureNeuroleptics: antischizophrenic drugs
Higher affinity for D2 correlates to effectiveness
Limitations of the Dopamine Theory
4 key discoveries that cannot by explained by the D2 version of the theory:
1. Receptors other than D2 are involved Glutamate, GABA & 5-HT Atypical neuroleptics developed to act on these
non-D2 receptors (ex: clozapine)
2. It takes weeks of neuroleptic therapy to alleviate symptoms
Despite the fact that neuroleptics can block activity at D2 receptors within hours
Limitations of the Dopamine Theory
3. Schizophrenia is associated with widespread brain damage
Not just limited to dopaminergic circuits
4. Neuroleptics are only marginally effective Not effective in all cases When they do have an effect, it is generally only on
some of the symptoms More effective in treating the positive symptoms
Affective Disorders: Depression & Mania
Affective Disorders: Any psychiatric disorder characterized by disturbances of mood or emotion Aka mood disorders
Depression
Experiencing periodic depression is a normal reaction to loss
However, some people have an increased tendency toward depression They repeatedly fall into deep despair & experience
anhedonia (inability to experience pleasure), often for no apparent reason
Depression
Depression can be so extreme that it is almost impossible for them to complete necessary daily tasks (keep a job, relationships, eating, personal hygiene)
Often have sleep issues & thoughts of suicide
When this condition lasts over 2 weeks, it is classified as clinical depression or major depressive disorder
Mania
Mania: Characterized by overconfidence, impulsivity, distractibility & high energy Generally the opposite of depression
During mild mania: Talkative, energetic, impulsive, positive & very confident Can be great at a job and/or very fun
Full-blown mania: Unbridled enthusiasm, incessant talking that jumps
topics, grandiosity, high energy, distractability, impulsiveness
Often leads to disaster, failed relationships, unfinished projects
Major Categories of Affective Disorders
Bipolar affective disorder: Depressive patients who experience periods of mania
Unipolar affective disorder: Depressive patients who do not experience mania
Reactive depression: Depression triggered by a negative experience (a
death, job loss)Endogenous depression:
Depression with no apparent cause
Probability of suffering from clinical depression during a lifetime is 10%
Women 2x more unipolar affective disorder than men (bipolar equal)
Risk of suicide in clinically depressed individuals is 5%
Affects all agesAffective disorders associate with heart
disease And bone loss in women
Causal Factors in Affective Disorders
Genetic factorsSeasonal affective disorder (SAD):
Attacks of depression & lethargy recur every winter Triggered by reduction of sunlight Light therapy can reduce symptoms
Postpartum depression: Depression experienced by some women after giving
birth
Antidepressant Drugs
4 major classes of drugs for the treatment of affective disorders:
1. Monoamine oxidase inhibitors2. Tricyclic antidepressants3. Selective monoamine-reuptake inhibitors4. Mood stabilizers
Monoamine Oxidase Inhibitors (MAOIs)
Monoamine agonist that increases the levels of monoamines by inhibiting the activity of monoamine oxidase (MAO), the enzyme that breaks down monoamine NTs
MAO inhibitors have several side effects, including the cheese effect Consuming foods high in tyramine
(cheese, wine, pickles) have risk of stroke from surges in blood pressure
Tricyclic Antidepressants
Named for the 3 rings of their chemical structure
Work by blocking the reuptake of serotonin & norepinephrine
Safer than MAOIs
Selective Monoamine-Reuptake Inhibitors
Selective serotonin-reuptake inhibitors (SSRIs): Serotonin agonists that block the reuptake of serotonin from
the synapse Prozac, Paxil, Zoloft, etc. Few side effects Act against a wide range of psychological
disorders in addition to depression
Selective norepinephrine-reuptake inhibitors (SNRIs)
Mood Stabilizers
Developed because other antidepressants often triggered mania
Mechanism of action is unknownEx: Lithium (a metallic ion)
Brain Pathology & Affective Disorders
MRI studies have shown reductions in overall brain size & in many different brain structures in bipolar patients However, lots of variation
2 structures are often abnormal: Amygdala Anterior cingulate cortex (and often the connections between them)
Monoamine Theory of Depression
Depression is associated with underactivity at serotonergic & noradrenergic synapses
Largely based on the fact that many of the drugs found to alleviate depression work as agonists of 5-HT, NE or both
Up-regulation: A compensatory increase in # of receptors for a NT when there is an insufficient amount of that NT released at a synapse Autopsies of clinically depressed individuals often
have more 5-HT & NE receptors than normal
Diathesis-Stress Model of Depression
Some people inherit a diathesis (genetic susceptibility) & stress exposure in early life causes them to be permanently sensitized, causing them to overreact to mild stressors for the rest of their lives The diathesis alone cannot initiate the disorder
Indirect evidence Depressed individuals release more stress hormones
Treatment of Depression with Brain Stimulation
Significant therapeutic effects of chronic brain stimulation through an implanted electrode
Stimulates the anterior cingulate gyrusPermanently embedded under the skin to
give continual pulsesExtreme measure given to those who do not
respond to conventional treatments
Anxiety Disorders
Anxiety: Chronic fear that persists in the absence of any direct threat Psychological correlate of stress Adaptive when it motivates effective coping behaviors Maladaptive when it is so severe it disrupts normal
functioning (anxiety disorders)Anxiolytic: anxiety reducingAnxiogenic: anxiety provoking
Anxiety Disorders
All anxiety disorders associated with feelings of anxiety (fear, worry, despondency) & variety of physiological stress reactions (tachycardia, hypertension, nausea, breathing difficulty, sleep disturbances, high glucocorticoid levels)
Most prevalent psychiatric disorder17% of people have one at some point in their
lives Women 2x
5 Classes of Anxiety Disorders
1. Generalized Anxiety Disorders: Characterized by stress responses & extreme feelings of
anxiety that occur in the absence of any obvious reason
2. Phobic Anxiety Disorders: Similar to GAD but triggered by a specific object (ex:
spiders, dogs) or situation (ex: flying, darkness) Agoraphobia: pathological fear of public places & open
spaces
3. Panic Disorders: Characterized by rapid-onset attacks of extreme fear &
severe symptoms of stress (choking, heart palpitations, shortness of breath)
5 Classes of Anxiety Disorders
4. Obsessive-Compulsive Disorders: Characterized by frequently recurring,
uncontrollable, anxiety-provoking thoughts (obsessions) & impulses (compulsions)
The compulsive behavior is done to alleviate the anxiety associated with the obsessions
5. Posttraumatic Stress Disorder: Persistent pattern of psychological distress
following exposure to extreme stress (ex: war, sexual assault)
Etiology of Anxiety Disorders
Genetic componentLarge experiential component
Because the anxiety often has an identifiable trigger, it is easier to assess the influence of experience in these types of disorders
Pharmacological Treatment of Anxiety Disorders
3 categories of drugs1. Benzodiazepines
Most widely prescribed psychoactive drugs Ex: Valium Several adverse side effects Highly addictive; so only for short-term use Thought to work by agonizing GABA receptors
2. Serotonin Agonists Advantage of specificity; doesn’t cause the side effects
associated with benzos But does have its own side effects
3. Antidepressant Drugs Common comorbidity (tendency to occur together in the same
individual) of depression & anxiety
Neural Bases of Anxiety Disorders
Substantial overlap in brain areas involved in anxiety & affective disorders Amygdala, anterior cingulate cortex But with anxiety disorders, there is no gross damage
(as opposed to shrinkage with affective) Increased activity in the amygdala of a phobic patient
when shown a picture of ex: a spider
Tourette Syndrome
A disorder of tics Involuntary, repetitive, stereotyped movements of vocalizations
Many people with this disorder have no symptoms other than tics
Typically begins in childhood with simple motor tics (blinking), with symptoms growing more complex & severe with age (hitting, hopping, lewd gestures)
Verbal tics can include barking, grunting, cursing (coprolalia), echolalia
Symptoms usually reach a peak after a few years & often subside as the patient matures
Tourette Syndrome
0.7% of the population 3x more frequent in males
Major genetic componentSome patients also have ADD/ADHD and/or
OCDAlthough tics are involuntary, they can be
temporarily be suppressed with great effort from the patient
Neuropathology of Tourette Syndrome
Very difficult to studyPeople with this disorder often have smaller
caudate nucleiSome evidence of thinning in sensorimotor
cortex areas that control the face, mouth & voice box
Treatment of Tourette Syndrome
Tics usually treated with neuroleptics Can reduce tics by about 70% However, often patients won’t take them because of
the adverse side effects