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Medicine Basics

Human Biology


The human body's 12 systems work together to ensure that we stay alive, healthy, and thrive:

  • The cardiovascular (or circulatory) system transports blood, oxygen, and nutrients throughout the body.

  • The digestive system takes in and processes food, and expels waste.

  • The endocrine system produces hormones that regulate metabolism, growth and development, tissue function, sexual reproduction, sleep, and mood.

  • The immune system fights infection caused by pathogens, like bacteria and viruses.

  • The integumentary system   your skin! And it protects your soft and squishy interior from damage by external dirt, pathogens, and trauma.

  • The lymphatic system is part of the immune system and complementary to the circulatory system. It keeps body fluid levels in balance and defends against infections.

  • The muscular system facilitates movements of our bodies, from reaching for the remote control to smashing out an intense workout in the boxing ring.

  • The nervous system, which consists of your brain, the spinal cord, and all the nerves throughout your body, controls movement, balance, the five senses, thought processes, and awareness.

  • The reproductive system— allows us to make babies.

  • The respiratory system facilitates breathing; more specifically, the intake of oxygen and expulsion of carbon dioxide.

  • The skeletal system provides a strong and durable framework upon which all your meat hangs, while helping to protect your delicate internal organs.

  • The urinary system expels waste and extra water that the body doesn't need.



The Heart is the bodies pump and hardest working muscle. Atrium is responsible for filling the ventricle which does the real pumping. The left side supplies the lungs, the right the rest of the body. Problems include leaky valves, blocked arteries and  electrical problems. 

Blocked arteries delivering blood to the heart muscle can kill parts of the muscle leading to a "heart attack" which  are mostly fatal. The American College of Cardiology reports that the earliest documented case of coronary atherosclerosis  was in an Egyptian princess who lived between 1580 and 1550 B.C.  Today, lowering blood cholesterol (fats) and early detection with surgical intervention for valves and arteries, with arthroscopic becoming much more common. Once the muscle is damaged, blood thinners are used to reduce pump load.

Leaky valves are repaired or replaced with artificial, pig or human cadaver valves.

The cardiovascular center provides a rapid, neural mechanism for the regulation of blood pressure by managing cardiac output or by adjusting blood vessel diameter. Located in the medulla oblongata of the brain stem, it consists of three distinct regions:

  • The cardiac center stimulates cardiac output by increasing heart rate and contractility. These nerve impulses are transmitted over sympathetic cardiac nerves.

  • The cardiac center inhibits cardiac output by decreasing heart rate. These nerve impulses are transmitted over parasympathetic vagus nerves.

  • The vasomotor center regulates blood vessel diameter. Nerve impulses transmitted over sympathetic motor neurons called vasomotor nerves innervate smooth muscles in arterioles throughout the body to maintain vasomotor tone, a steady state of vasoconstriction appropriate to the region.

The cardiovascular center receives information about the state of the body through the following sources:

  • Baroreceptors are sensory neurons that monitor arterial blood pressure. Major baroreceptors are located in the carotid sinus (an enlarged area of the carotid artery just above its separation from the aorta), the aortic arch, and the right atrium.

  • Chemoreceptors are sensory neurons that monitor levels of CO 2 and O 2. These neurons alert the cardiovascular center when levels of O 2 drop or levels of CO 2 rise (which result in a drop in pH). Chemoreceptors are found in carotid bodies and aortic bodies located near the carotid sinus and aortic arch.

  • Higher brain regions, such as the cerebral cortex, hypothalamus, and limbic system, signal the cardiovascular center when conditions (stress, fight‐or‐flight response, hot or cold temperature) require adjustments to the blood pressure.

The kidneys provide a hormonal mechanism for the regulation of blood pressure by managing blood volume.

  • The renin‐angiotensin‐aldosterone system of the kidneys regulates blood volume. In response to rising blood pressure, the juxtaglomerular cells in the kidneys secrete renin into the blood. Renin converts the plasma protein angiotensinogen to angiotensin I, which in turn is converted to angiotensin II by enzymes from the lungs. Angiotensin II activates two mechanisms that raise blood pressure.

Various substances influence blood pressure. Some important examples follow:

  • Angiotensin II constricts blood vessels throughout the body (raising blood pressure by increasing resistance to blood flow). Constricted blood vessels reduce the amount of blood delivered to the kidneys, which decreases the kidneys' potential to excrete water (raising blood pressure by increasing blood volume).

  • Angiotensin II stimulates the adrenal cortex to secrete aldosterone, a hormone that reduces urine output by increasing retention of H 2O and Na + by the kidneys (raising blood pressure by increasing blood volume).

  • Epinephrine and norepinephrine, hormones secreted by the adrenal medulla, raise blood pressure by increasing heart rate and the contractility of the heart muscles and by causing vasoconstriction of arteries and veins. These hormones are secreted as part of the fight‐or‐flight response.

  • Antidiuretic hormone (ADH), a hormone produced by the hypothalamus and released by the posterior pituitary, raises blood pressure by stimulating the kidneys to retain H 2O (raising blood pressure by increasing blood volume).

  • Atrial natriuretic peptide (ANP), a hormone secreted by the atria of the heart, lowers blood pressure by causing vasodilation and by stimulating the kidneys to excrete more water and Na +(lowering blood pressure by reducing blood volume).

  • Nitric oxide (NO), secreted by endothelial cells, causes vasodilation.

  • Nicotine in tobacco raises blood pressure by stimulating sympathetic neurons to increase vasoconstriction and by stimulating the adrenal medulla to increase secretion of epinephrine and norepinephrine.

  • Alcohol lowers blood pressure by inhibiting the vasomotor center (causing vasodilation) and by inhibiting the release of ADH (increasing H 2O output, which decreases blood volume).


Blood pressure mis-regulation is a leading cause of strokes - blood clots that damage the lungs or brain. There are a number of drugs to reduce blood pressure; Diuretic, Beta-blockers (carvedilol) , ACE inhibitors, Angiotensin II receptor blockers (Valsartan), Calcium channel blockers, Alpha blockers, Alpha-2 Receptor Agonists, Combined alpha and beta-blockers, Central agonists, Peripheral adrenergic inhibitors, Vasodilators.


Electrical problems include atrial fibrillation, ventricle fibrillation, and  blocked signals within the heart. Ventricle fibrillation  or "cardiac arrest" is very serious which requires electro shock within 2 minutes. Atrial fibrillation is rarely immediately fatal, and is more common in large athletic males over 50, probably due to enlarged heart.  Can be source of blood clots that damage lungs or brain but  can be treated with drugs, or ablation to reconfigure conduction paths inside the heart.  Heart block requires a pacemaker fix. First pacemaker in 1958.


Enables the intake of oxygen and expulsion of carbon dioxide, so it is the primary path for airborne pollution and infections. Is damaged by particles and tar from smoking as trigger for COPD and lung cancer. At risk for loss of function from asthma, an immune overresponse. Embolism's from blood clots migrating from the heart can kill segments of the lungs. Susceptible to bacterial and viral infections causing pneumonia. The lungs are warm damp area with small cavities where bugs can thrive and are difficult to treat. Bacterial pneumonia is treated with antibiotics which are susceptible to becoming antibiotic resistant. 

Bacterial respiratory infections are generally more aggressive than viral. While having COPD makes you more susceptible to viral pneumonia, the infection is also not uncommon among those with a healthy immune system. Bacterial pneumonia is considered a sign of a compromised immune system; when your body doesn't adequately fight an infection, it can worsen rapidly

Lower respiratory tract infection (LRTI) is a term often used as a synonym for pneumonia but can also be applied to other types of infection including lung abscess and acute bronchitis. Symptoms include shortness of breath, weakness, fever, coughing and fatigue.[3] A routine chest X-ray is not always necessary for people who have symptoms of a lower respiratory tract infection.[4]

Influenza affects both the upper and lower respiratory tracts.[citation needed]

Antibiotics are the first line treatment for pneumonia; however, they are neither effective nor indicated for parasitic or viral infections. Acute bronchitis typically resolves on its own with time.[citation needed]


I think it is important! Susceptible to catastrophic loss of function strokes from blood clots  interrupting blood flow.  Treatment with clot busting drugs within 4 hours is critical after scanning to eliminate any blood leaks that will be made much worse by clot busters.  If damage is mild, the brain can be retrained by mental exercises.   


If there is an aneurism, or weaknesses in blood vessel walls, a break can cause serious damage. Because the brain is a dense 3D structure of neurons, it is susceptible to inoperable cancer. 


In old age it is susceptible to growth abnormalities such as  Lewy bodies causing Parkinson's. Lewy bodies are the inclusion bodies – abnormal aggregations of protein – that develop inside nerve cells affected by Parkinson's disease. Alzheimer's. caused by  amyloid plaques and tau tangles.  Amyloid plaques are formed by mis folds of the protein especially abundant in neurons.   Multiple concussions cause Chronic traumatic encephalopathy, or CTE. Autopsies of deceased NFL players show a buildup of a protein called tau around the blood vessels. CTE is thought to cause areas of the brain to waste away (atrophy). 


Their research found that tau-induced “jumping genes” — which can relocate or copy themselves to other locations in the genome — form double-stranded RNA.  The researchers detected accumulation of double-stranded RNA in postmortem brain tissue from patients with Alzheimer’s disease and progressive supranuclear palsy and in brains of mouse and fruit fly models of tauopathy.

There is evidence of a genetic susceptibility to both Parkinson's and CTE.

Sex bits

Female sex bits include; breast, clitoris, ovaries, and uterus.

Breast is the 4th most common cancer, and equal first for women when accounting for the fact that only half the population is at risk. There is a significant genetic susceptibility, and it is one of the first where genetic typing directs the therapy. 

Ovarian, cervical  and uterine cancers are all common. but do not make the 10 worst list.  It is preferable to retain ovaries wherever possible as they provide female sex hormones, if they are lost then menopause happens immediately. 

Male sex bits include  penis, prostate, testicles. The prostate switches between semen and urine as needed. Testicles make semen and the male hormones responsible for the changes in voice box, and Adam's apple in puberty.   Prostate cancer is a significant killer, but does leave markers in blood that can be used for early detection. Testicular cancer is common. Erectile dysfunction is common, and is not helped by blood pressure med however Viagra has stiffened men's resolve.


The digestive tract consists of  stomach, intestines and liver. The stomach is responsible for breaking down food .The thick mucous-membrane lining of the walls is densely packed with small gastric glands; these secrete a mixture of enzymes and hydrochloric acid that partly digest proteins and fats., and the intestines for absorbing nutrients into the blood stream. The small intestine receives digestive enzymes from the pancreas and liver to continue to break down ingested food, and absorbs proteins  and sugars. The large intestines manages residues and the absorption of water and ions. Healthy intestines support a  "biome" of several bacteria. This biome can be disrupted by antibiotics being used to treat other infections. Replenishing the biome with healthy samples from donors is a solution. ​

The digestive system is the path of entry for water and food born infections such as cholera, hepatitis, typhoid and dysentery. These are dangerous diseases of poor sanitation that are still an issue in 3rd world countries and after natural disasters such as earthquakes. 


Diseases of the intestines include Celiac's, diverticulitis, inflammatory bowl, and irritable bowl.

Celiac disease, eating gluten triggers an immune response in your small intestine. Over time, this reaction damages your small intestine's lining and prevents it from absorbing some nutrients (malabsorption). In diverticulitis pockets form in the intestine walls that get inflamed and infected. Inflammatory bowl is an auto immune attack of the intestine lining. Irritable bowl is caused by excessive muscular contractions of the intestines. 

Colon cancer is the 2nd most common cancer,  early detection by routine colonoscopy has had a major impact on outcomes. 

The liver's main job is to filter the blood coming from the digestive tract, before passing it to the rest of the body. The liver also detoxifies chemicals and metabolizes drugs. As it does so, the liver secretes bile that ends up back in the intestines. Liver is damaged by excess alcohol consumption. 

Endocrine system

The endocrine system[1] is a messenger system comprising feedback loops of the hormones released by internal glands of an organism directly into the circulatory system, regulating distant target organs.  In humans, the major endocrine glands are the thyroid glandparathyroid glandpituitary glandpineal gland, the testes (male), ovaries (female), and the adrenal glands. The hypothalamuspancreas, and thymus also function as endocrine glands, among other functions. Other organs, such as the kidneys, also have roles within the endocrine system by secreting certain hormones. The study of the endocrine system and its disorders is known as endocrinology.​

  • Posterior pituitary gland    Stores and secretes hormones such as antidiuretic hormone (ADH) which is synthesized by supraoptic nucleus of hypothalamus and oxytocin which is synthesized by paraventricular nucleus of hypothalamus. ADH functions to help the body to retain water; this is important in maintaining a homeostatic balance between blood solutions and water. Oxytocin functions to induce uterine contractions, stimulate lactation, and allows for ejaculation.[7][8]

  • Thyroid gland   regulates  levels of TSH, produced by the anterior pituitary gland, which further regulates the metabolic activity and rate of all cells, including cell growth and tissue differentiation.

  • Parathyroid gland   Secretes parathyroid hormone (PTH). PTH acts on bone, the kidneys, and the GI tract to increase calcium reabsorption and phosphate excretion. In addition, PTH stimulates the conversion of Vitamin D . 

  • Adrenal glands​   Produces adrenalin​.

  • Pancreas   The pancreas secrete hormones to maintain homeostatic blood sugar. Insulin is produced and excreted to lower blood sugar to normal levels, whereas glucagon increases blood glucose level.[9]

  • Thymus   regulates immune function T cell production along with bone marrow.

Pancreas is subject to auto immune attack in Diabetes Type 1, and control failure in Type 2. Pancreatic cancer is a growing problem because currently there is no early detection protocol. 

Thyroid is subject to auto-immune attack in Hashimoto's (hypo-) and Graves (hyper-) diseases.


The kidney participates in the control of the volume of various body fluids, fluid osmolalityacid–base balance, various electrolyte concentrations, and removal of toxins, including uric acid. They convert a precursor of vitamin D to its active form, calcitriol; and synthesize the hormones erythropoietin and renin.

Mis-regulation of uric acid is the root cause of gout. 

Chronic kidney disease (CKD) has been recognized as a leading public health problem worldwide. The global estimated prevalence of CKD is 13.4%, and patients with kidney failure needing renal replacement therapy are estimated between 5 and 7 million.[3] Procedures used in the management of kidney disease include chemical and microscopic examination of the urine (urinalysis), measurement of kidney function by calculating the estimated glomerular filtration rate (eGFR) using the serum creatinine; and kidney biopsy and CT scan to evaluate for abnormal anatomy. Dialysis and kidney transplantation are used to treat kidney failure; one (or both sequentially) of these are almost always used when renal function drops below 15%. Nephrectomy is frequently used to cure renal cell carcinoma.

Motion Systems 

Bones in the skeleton provides the scaffold for organs. 

Joints between bones enable mobility. - arthritis, wear, bone spurs, gout

Cartlidge provides the friction free surfaces at the contact points between bones.

Ligaments link the bones in a joint, and limit range of motion

Tendons connect bones to muscles

Muscles expand and contract to enable motion 

Nerves send message to activate muscles

Bursa provides friction relief where tendons rub over bones

Inner ear provides balance. 

Common problems include;

  • Broken bones - immobilization to allow mending, support structure sometimes required

  • Damaged ligaments, tendons, muscles - ruptures require surgery. 

  • Cartilage wear in arthritis, most common cause of joint replacement.

  • Cartilage distortion, particular problem between vertebrae putting pressure on spinal column nerves

  • Inflamed bursa treated with rest and steroids

  • Muscles subject to wasting diseases and atrophy

  • Nerves -   autoimmune diseases   include: multiple sclerosisGuillain-Barré syndrome (a rare condition in which the immune system attacks the peripheral nerves), lupus, and inflammatory bowel disease.  

  • Muscle/nerve interface diseases such as Myasthenia gravis, ALS motor neuron disease.


We rely on eyes, nose, tongue, ears to experience our environment. 


Eyes are particularly important and delicate. Focusing problems have been fixed with glasses for centuries. Lenses become opaque from cataracts and  lens replacement has become routine. Damage to the optic nerve from excess pressure in the eye ball causes glaucoma, a leading cause of blindness. Diabetes can restrict blood flow to the retina. The retina can become detached from the eye surface. 


Skin keeps the insides from falling out. It has a remarkable capacity for self repair. Skin cancer is dangerous, managed by inspection and early intervention. Minimizing sun exposure is a key preventative. 

Lymphatic system

The lymphatic system, or lymphoid system, is an organ system in vertebrates that is part of the immune system, and complementary to the circulatory system. It consists of a large network of lymphatic vesselslymph nodes, lymphatic or lymphoid organs, and lymphoid tissues.[1][2] The vessels carry a clear fluid called lymph (the Latin word lympha refers to the deity of fresh water, "Lympha")[3] back towards the heart, for re-circulation.

Unlike the circulatory system that is a closed system, the lymphatic system is open. The human circulatory system processes an average of 20 litres of blood per day through capillary filtration, which removes plasma from the blood. Roughly 17 litres of the filtered blood is reabsorbed directly into the blood vessels, while the remaining three litres are left in the interstitial fluid. One of the main functions of the lymphatic system is to provide an accessory return route to the blood for the surplus three litres.[4]

The other main function is that of immune defense. The primary (or central) lymphoid organs generate lymphocytes . The thymus and the bone marrow constitute the primary lymphoid organs involved in the production of lymphocytes. A lymphocyte is a type of white blood cell (leukocyte) in the immune system of most vertebrates.[1] Lymphocytes include  T cells.  Lymphocytes make up between 18% and 42% of circulating white blood cells.

The lymph system is also a path for cancer cells to move around and metastasize to other organs.

Immune system

Upon detecting a pathogen, microphages (or white blood cells) will surround and immobilize it, literally consuming it with their bodies. Antibodies are the high-powered weaponry made by white blood cells to destroy the invaders. Vaccines are designed to trigger the bodies immune response and create the antibodies without the infection.  

The standard model of infections is SIR, and R0 is the measure of how easily the disease spreads - how many new people are infected by each infected person. Covid 19 was a highly contagious. 

Issues include, immune compromised, over stimulation such as allergies, auto-immune. 

Autoimmune disease by prevalence:

Immune over-reaction

Allergies, also known as allergic diseases, refer to a number of conditions caused by the hypersensitivity of the immune system to typically harmless substances in the environment.[11] These diseases include hay feverfood allergiesatopic dermatitisallergic asthma, and anaphylaxis.[1] Symptoms may include red eyes, an itchy rashsneezingcoughing, a runny noseshortness of breath, or swelling.[12] Note: food intolerances and food poisoning are separate conditions.[3][4]

Common allergens include pollen and certain foods.[11] Metals and other substances may also cause such problems.[11] Food, insect stings, and medications are common causes of severe reactions.[2] Their development is due to both genetic and environmental factors.[2] The underlying mechanism involves immunoglobulin E antibodies (IgE), part of the body's immune system, binding to an allergen and then to a receptor on mast cells or basophils where it triggers the release of inflammatory chemicals such as histamine.[13] Diagnosis is typically based on a person's medical history.[3] Further testing of the skin or blood may be useful in certain cases.[3] Positive tests, however, may not necessarily mean there is a significant allergy to the substance in question.


A compromised immune system can be inherited as in the "boy in the bubble", develop as a disease as in common variable immunodeficiency disease, It also results from advanced or untreated HIV infection.  Cancer treatment from chemotherapy or X rays damages the immune system.  Transplant recipients must take drugs to suppress their immune system to avoid rejection. 



Medical issues come from external sources such as infections, pollution and accidents. Wear and tear with age are responsible for blocked arteries, worn joints etc. Abnormal cell growth is responsible for cancers, and brain damage in Alzhiemers, Parkinson's, and CTE. Mis-regulation causes blood pressure problems, gout, diabetes 2. Immune system failures include auto-immune where the body attacks healthy cells such as diabetes 1, Hashimoto's and Graves. Immune overreaction causes allergies. Immune system failure "immunocompromised" makes the unable to defend any infections. 

  • Flu has an R0 of 1.5 

  • Smallpox has an R0 of 3

  • Polio has an R0 of 4-6

  • Covid 19 has an R0 of 7

  • Mumps has an R0 of 10-12

  • Chickenpox has an R0 of 10-12

  • Pertussis has an R0  of 15-17

  • Measles has an R0  of 16-18

Mental disorder

A mental disorder, also referred to as a mental illness[5] or psychiatric disorder, is a behavioral or mental pattern that causes significant distress or impairment of personal functioning.[6] Such features may be persistent, relapsing and remitting, or occur as single episodes. Many disorders have been described, with signs and symptoms that vary widely between specific disorders.[7][8] Such disorders may be diagnosed by a mental health professional, usually a clinical psychologist or psychiatrist.

In 2019, common mental disorders in the US include 

Substance Abuse

The National Bureau of Economic Research reports that individuals with a history of mental illness are 25% more likely to consume alcohol, 69% more likely to consume cocaine, and 94% more likely to consume cigarettes.¹ When a person struggles with substance misuse and a mental illness, this is known as a dual diagnosis or co-occurring disorder.

Mood disorders, especially major depressive disorder (MDD) and bipolar disorder (BD), often coincide with substance use disorders (SUDs). Prevalence of substance use disorders in people with BD range from 20% to 70% and from 10% to 30% in persons with MDD. Alcohol use disorder is the most common SUD in individuals with BD, occurring in about 42%, and cannabis use disorder is the next most common, at about 20%.²

Depression is a mental illness frequently co-occurring with substance use. The relationship between the two disorders is bi-directional, meaning that people who misuse substances are more likely to suffer from depression, and vice versa. People who are depressed may drink or use drugs to lift their mood or escape from feelings of guilt or despair. But substances like alcohol, which is a depressant, can increase fatigue, affecting concentration, inhibitions, decision-making and reaction times. Alcohol misuse may lead to falling asleep at work or school.

Teen mental health

In high school, 50% sexually active, 2% gay, 7% lesbian.


Around 1 in 3 high school girls in the U.S. have seriously considered attempting suicide, according to new results from a Centers for Disease Control and Prevention survey from 2021, up from less than a fifth of teen girls in 2011. And more than half of teen girls, 57%, reported feeling "persistently sad or hopeless" — a record high number.

By contrast, 14% of high school boys told the 2021 survey that they had seriously considered attempting suicide, up from 13% in 2011.

In girls, frequent social-media use seemed to harm health when it led to either cyberbullying and/or inadequate sleep and exercise.

  • Girls enter  puberty earlier and so have less experience to manage.  

  • Girls have greater emotional sensitivity than boys

  • Girls place more importance on relationships than boys.

  • Girls are more likely than boys to have excessive empathy

  • Girls are more likely than boys to co-ruminate (share with friends)

Psychopath leaders

Unfortunately, leadership seems to self select psychopaths. Popular labels such as psychopath (or sociopath) do not appear in the DSM or ICD but are linked by some to these diagnoses. Psychopathy, sometimes considered synonymous with sociopathy, is characterized by persistent antisocial behavior, impaired empathy and remorse, and bolddisinhibited, and egotistical traits.[1][2][3]  

"Psychopaths are social predators who charm, manipulate, and ruthlessly plow their way through life, leaving a broad trail of broken hearts, shattered expectations, and empty wallets. Completely lacking in conscience and in feelings for others, they selfishly take what they want and do as they please, violating social norms and expectations without the slightest sense of guilt or regret." —Robert D. Hare, 1993,

Kevin Dutton, author of The Wisdom of Psychopaths, is a research psychologist at the Department of Experimental Psychology at the University of Oxford, with a specialty in psychopathy. He analyzed past and present leaders for their relative level of psychopathy. In an article for Scientific American, Dutton argues that psychopathy can be defined by three categories of characteristics, including fearless dominance, self-centered impulsivity, and coldheartedness.

Dutton generally considers a man a psychopath if he scores at least a 155 on his scale and a woman a psychopath if she scores at least a 139.5. President-elect Donald Trump scores a 171 on Dutton’s scale in part because of high scores in the perceived traits of fearless dominance and self-centered impulsivity (though Dutton has not examined Trump in person). But he’s by no means the only U.S. president who could be considered a psychopath. “Politics came out as a profession in which an official consignment of legalized, precision-engineered psychopathy would come in rather handy,” writes Dutton.

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 Anxiety disorder

An anxiety disorder is anxiety or fear that interferes with normal functioning may be classified as an anxiety disorder.[37] Commonly recognized categories include specific phobiasgeneralized anxiety disordersocial anxiety disorderpanic disorderagoraphobiaobsessive–compulsive disorder and post-traumatic stress disorder.

Mood disorder

Other affective (emotion/mood) processes can also become disordered. Mood disorder involving unusually intense and sustained sadness, melancholia, or despair is known as major depression (also known as unipolar or clinical depression).  Bipolar disorder (also known as manic depression) involves abnormally "high" or pressured mood states, known as mania or hypomania, alternating with normal or depressed moods.


Psychotic disorder

Patterns of belief, language use and perception of reality can become dysregulated (e.g., delusionsthought disorderhallucinations). Psychotic disorders in this domain include schizophrenia,  


The fundamental characteristics of a person that influence thoughts and behaviors across situations and time—may be considered disordered if judged to be abnormally rigid and maladaptive.  A number of different personality disorders are listed, including those sometimes classed as eccentric, such as paranoidschizoid and schizotypal personality disorders; types that have described as dramatic or emotional, such as antisocialborderlinehistrionic or narcissistic personality disorders; and those sometimes classed as fear-related, such as anxious-avoidantdependent, or obsessive–compulsive personality disorders.   If an inability to sufficiently adjust to life circumstances begins within three months of a particular event or situation, and ends within six months after the stressor stops or is eliminated, it may instead be classed as an adjustment disorder. T 

Eating disorder

Eating disorders involve disproportionate concern in matters of food and weight.[37] Categories of disorder in this area include anorexia nervosa, bulimia nervosaexercise bulimia or binge eating disorder.[44][45]

Sleep disorder

Sleep disorders are associated with disruption to normal sleep patterns. A common sleep disorder is insomnia,

Sexual disorders

Include dyspareunia and various kinds of paraphilia (sexual arousal to objects, situations, or individuals that are considered abnormal or harmful to the person or others).

Impulse control disorder:

People who are abnormally unable to resist certain urges or impulses that could be harmful to themselves or others, may be classified as having an impulse control disorder, and disorders such as kleptomania (stealing) or pyromania (fire-setting). Various behavioral addictions, such as gambling addiction, may be classed as a disorder. Obsessive–compulsive disorder can sometimes involve an inability to resist certain acts but is classed separately as being primarily an anxiety disorder.

Substance use disorder:

This disorder refers to the use of drugs (legal or illegal, including alcohol) that persists despite significant problems or harm related to its use. Substance dependence and substance abuse fall under this umbrella category in the DSM. Substance use disorder may be due to a pattern of compulsive and repetitive use of a drug that results in tolerance to its effects and withdrawal symptoms when use is reduced or stopped.

Dissociative disorder:

People with severe disturbances of their self-identity, memory, and general awareness of themselves and their surroundings may be classified as having these types of disorders,  (which was previously referred to as multiple personality disorder or "split personality").

Cognitive disorder:

These affect cognitive abilities, including learning and memory. This category includes delirium and mild and major neurocognitive disorder (previously termed dementia).

Developmental disorder:

These disorders initially occur in childhood. Some examples include autism spectrum disorder, oppositional defiant disorder and conduct disorder, and attention deficit hyperactivity disorder (ADHD), which may continue into adulthood. Conduct disorder, if continuing into adulthood, may be diagnosed as antisocial personality disorder (dissocial personality disorder in the ICD).

Dissocial personality disorder

People with dissocial personality disorder exhibit traits of impulsivity, high negative emotionality, low conscientiousness and associated behaviors, including irresponsible and exploitative behavior, recklessness and deceitfulness. Popular labels such as psychopath (or sociopath) do not appear in the DSM or ICD but are linked by some to these diagnoses. Psychopathy, sometimes considered synonymous with sociopathy, is characterized by persistent antisocial behavior, impaired empathy and remorse, and bolddisinhibited, and egotistical traits.[1][2][3] Different conceptions of psychopathy have been used throughout history that are only partly overlapping and may sometimes be contradictory.  Although no psychiatric or psychological organization has sanctioned a diagnosis titled "psychopathy", assessments of psychopathic characteristics are widely used in criminal justice settings in some nations and may have important consequences for individuals.[specify] The study of psychopathy is an active field of research. The term is also used by the general public, popular press, and in fictional portrayals.[11][12] While the term is often employed in common usage along with "crazy", "insane", and "mentally ill", there is a categorical difference between psychosis and psychopathy. 

Factitious disorders 

are diagnosed where symptoms are thought to be reported for personal gain. Symptoms are often deliberately produced or feigned, and may relate to either symptoms in the individual or in someone close to them, particularly people they care for.

Relational disorder,

where the diagnosis is of a relationship rather than on any one individual in that relationship. The relationship may be between children and their parents, between couples, or others. There already exists, under the category of psychosis, a diagnosis of shared psychotic disorder where two or more individuals share a particular delusion because of their close relationship with each other.


There are a number of uncommon psychiatric syndromes, which are often named after the person who first described them, such as Capgras syndromeDe Clerambault syndromeOthello syndromeGanser syndromeCotard delusion, and Ekbom syndrome, and additional disorders such as the Couvade syndrome and Geschwind syndrome.


There is also a wide range of psychotherapists (including family therapy), counselors, and public health professionals. In addition, there are peer support roles where personal experience of similar issues is the primary source of expertise. 

A major option for many mental disorders is psychotherapy. There are several main types. Cognitive behavioral therapy (CBT) is widely used and is based on modifying the patterns of thought and behavior associated with a particular disorder. Other psychotherapies include dialectic behavioral therapy (DBT) and interpersonal psychotherapy (IPT). Psychoanalysis, addressing underlying psychic conflicts and defenses, has been a dominant school of psychotherapy and is still in use. Systemic therapy or family therapy is sometimes used, addressing a network of significant others as well as an individual.

Some psychotherapies are based on a humanistic approach. There are many specific therapies used for particular disorders, which may be offshoots or hybrids of the above types. Mental health professionals often employ an eclectic or integrative approach. Much may depend on the therapeutic relationship, and there may be problems with trustconfidentiality and engagement.

A major option for many mental disorders is psychiatric medication and there are several main groups. Antidepressants are used for the treatment of clinical depression, as well as often for anxiety and a range of other disorders. Anxiolytics (including sedatives) are used for anxiety disorders and related problems such as insomnia. Mood stabilizers are used primarily in bipolar disorder. Antipsychotics are used for psychotic disorders, notably for positive symptoms in schizophrenia, and also increasingly for a range of other disorders. Stimulants are commonly used, notably for ADHD.[121]

Despite the different conventional names of the drug groups, there may be considerable overlap in the disorders for which they are actually indicated, and there may also be off-label use of medications. These medications in combination with non-pharmacological methods, such as cognitive-behavioral therapy (CBT) are seen to be most effective in treating mental disorders.


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