Psychiatry The medical specialty that studies the anatomy and physiology of the brain and the functioning of the mind and uses diagnostic tests; medical, surgical, and psychiatric procedures; and drugs to treat psychiatric diseases.
Anatomy and Physiology The anatomical structures that pertain to psychiatry are located in the brain; psychiatry is concerned with physical symptoms and signs as well as behaviors that are the result of thoughts and emotions.
Anatomy Related to Psychiatry Limbic Lobe and Limbic System – The limbic lobe in the brain is located along the medial walls of the right and left cerebral hemispheres. – Includes some of each of the lobes of the cerebrum, plus a long extension of tissue into the temporal lobe.
Anatomy Related to Psychiatry (cont’d) Limbic Lobe and Limbic System (cont’d) – The limbic system consists of the limbic lobe, thalamus, hypothalamus, and several other smaller structures. – Links the unconscious mind to the conscious mind – Processes memories and controls emotion, mood, memory, motivation, and behavior
Figure 17-2 Limbic system
Anatomy Related to Psychiatry (cont’d) Hypothalamus – Located below the thalamus – Controls emotions of pleasure, excitement, fear, anger, sexual arousal, and bodily responses to these emotions – Contains the feeding center and satiety center
Anatomy Related to Psychiatry (cont’d) Hypothalamus (cont’d) – Regulates the sex drive and sexual behavior – Active in the learning process and helps short- term memories become permanent, long-term memories
Anatomy Related to Psychiatry (cont’d) Hippocampus – An elongated structure with a head and a tail that is located in each temporal lobe – Tail of the hippocampus connects to the hypothalamus – Stores long-term memories and helps compare present and past emotions and experiences
Anatomy Related to Psychiatry (cont’d) Fornix – Connects the hippocampus in each temporal lobe to the thalamus and to amygdaloid bodies
Anatomy Related to Psychiatry (cont’d) Amygdaloid bodies – Almond-shaped areas of grey, unmyelinated nerve tissue located in each temporal lobe – Involved in interpreting facial expressions and new social situations and identifying situations that could be dangerous – Integrate sensory information, thoughts, and long- term memories, and are most active during the emotions of fear, anger, and rage
Physiology of Emotion and Behavior An emotion is an intense state of feelings. An intense emotion connected with a particular situation causes that situation to imprint deeply in long-term memory; that situation, when later called to mind, brings with it those same intense emotions.
Physiology of Emotion and Behavior A person’s emotional state of mind may reflect many emotions at the same time, but the prevailing, predominant emotion is known as the person’s mood.
Physiology of Emotion and Behavior (cont’d) Emotions are normal forms of expression, but extremely intense, long-lasting, inappropriate, or absent emotions are signs of mental illness. Injury to the brain or changes in the levels of various neurotransmitters in the brain can produce abnormal emotions and behaviors.
Physiology of Emotion and Behavior (cont’d) The frontal lobe is the site of reasoning, judgment, planning, organizing, personality, creativity, and recent memories of all of those things. The frontal lobe exerts conscious control over alertness, concentration, and emotions.
Physiology of Emotion and Behavior (cont’d) The frontal lobe also analyzes situations, predicts future events, and weighs the benefits or consequences of actions taken.
Physiology of Emotion and Behavior (cont’d) Injury to the frontal lobe can produce these psychiatric symptoms: flat affect, disinterest, inability to concentrate, inappropriate laughing or crying, inappropriate social or sexual behavior, indifference to the consequences of behavior and actions, inability to plan or modify behavior, inability to abide by or create rules to govern behavior, inability to keep commitments, impulsiveness, or an absence of goal-directed behavior.
Physiology of Emotion and Behavior (cont’d) Injury to the hypothalamus can cause overeating and obesity, disinterest in eating, insomnia, or excessive sleepiness. Hyperstimulation of the amygdaloid bodies can cause violent, aggressive behavior Injury to or degeneration of the amygdaloid bodies can cause a loss of the emotions of anger and fear.
Physiology of Emotion and Behavior (cont’d) Injury to or degeneration of either hippocampus can cause the loss of all long- term memory. A patient with Alzheimer’s disease with degeneration of those areas may be unable to recognize his/her own face in the mirror.
Physiology of Emotion and Behavior (cont’d) Neurotransmitters are chemicals that relay messages from one neuron to the next. Neurotransmitters play an important role in emotion and behavior. Increased, decreased, or unbalanced levels of neurotransmitters can cause abnormal emotions and behaviors.
Physiology of Emotion and Behavior (cont’d) Norepinephrine – Neurotransmitter of the sympathetic division of the nervous system – Controls the involuntary processes such as the heart rate, respiratory rate, and blood pressure when the body is active or exercising – Increased level causes aggression, infatuation, and mania – Decreased level causes depression
Physiology of Emotion and Behavior (cont’d) Epinephrine – Neurotransmitter of the sympathetic division of the nervous system – Secreted to prepare the body for “fight or flight” – Increased level causes anxiety, social phobia, performance phobia, and panic attacks
Physiology of Emotion and Behavior (cont’d) Dopamine – Neurotransmitter in the brain – Cocaine, narcotic drugs, and alcohol increase the amount of dopamine, and this causes the euphoria and excitement (“high”) craved by addicts; it also causes infatuation. – A decreased level causes schizophrenia and depression.
Physiology of Emotion and Behavior (cont’d) Dopamine – The combination of an increased level of dopamine in the limbic system and a decreased level of dopamine in the frontal lobe causes paranoia.
Physiology of Emotion and Behavior (cont’d) Serotonin – Neurotransmitter in the brain and spinal cord. – A decreased level causes depression. – The combination of a decreased level of serotonin and an increased level of norepinephrine causes violent behavior.
Physiology of Emotion and Behavior (cont’d) GABA – Inhibitory neurotransmitter in the brain – A decreased level causes anxiety. – GABA stands for gamma-aminobutyric acid.
Psychiatric Therapies (cont’d) Electroconvulsive therapy (ECT) Family therapy Group therapy
Figure 17-9 Group therapy Kramer/Custom Medical Stock Photo, Inc.
Psychiatric Therapies (cont’d) Hypnosis Play therapy Psychoanalysis Psychotherapy
Psychiatric Therapies (cont’d) Systematic desensitization Therapeutic milieu
Drug Categories These categories of drugs are used to treat psychiatric Diseases and Conditions: – Antianxiety drugs – Antidepressant drugs – Antipsychotic drugs – Drugs for alcoholism – Drugs for bipolar disorder