Causes of Mental Illness
Predisposing factors Precipitating factors Perpetuating factors
The classification of causes
• Multiple – useful to group them together
Predisposing factors Constitution
• Determine vulnerability to other causes that act close to the time of illness, usually early in life
Genetic endowment Environment in utero Trauma at birth Social/psychological factors in development
• Family-linkage and twin studies play an important role in the development of mental disorders. • More common in people who are biologically related. • Susceptibility is passed on in families through genes. • Mental illnesses are linked to abnormalities in many genes. That is why a person inherits a susceptibility to a mental illness and doesn't necessarily develop the illness. • Mental illness itself occurs from the interaction of multiple genes and other factors , such as stress, abuse or trauma. • Mental illnesses that are genetically passed on include schizophrenia, depression
Study designs: Genetics
• Family risk studies: Affected people identified among relatives and these rates are compared to general population. The morbid risk that was higher amongst those who were related. • Twin studies: Comparisons were made among monozygotic twins and dizygotic twins. It was inferred that MZ>DZ. A more precise estimate can be made by comparing MZ twins reared apart and those reared together. (higher significance in etiology)
• Adoption studies: Comparisons made between adopted persons with a biological parent who has the disorder, and adopted persons with biological parents free from the disorder. A second study was made between biological parents and adoptive parents who have the disorder. These studies have been applied to schizophrenia and affective disorders, both of which point towards genetic causes.
• Maternal exposure to psychological stress or trauma, conditions of famine, obstetric birth complications, infections, and gestational exposure to alcohol or drugs. • Such factors have been hypothesized to affect specific areas of neurodevelopment. • Preterm birth is associated with almost half of all neurological birth defects.
• Maternal infections during pregnancy: measles, rubella, varicella, polio, influenza, toxoplasmosisMay lead to schizophrenia • Pediatric autoimmune neuropsychiatric disorder (PANDA) associated with the Streptococcus bacteria has been linked to obsessive-compulsive disorder(OCD)
Environment in utero
• Smoking mother’s child tend to develop depression and anxiety • Fetal alcohol syndrome can cause mental and physical impairments in mothers who consume alcohol during pregnancy • Children who are exposed to prenatal maternal anxiety, depression, or stress seem to be more likely develop anxiety, symptoms of attentiondeficit/hyperactivity disorder, reduced cognitive autism, schizophrenia and learning delay.
Fetal alcohol syndrome
Trauma during birth
• Fetal hypoxia can lead to autism • Children who have had traumatic births are more likely to be anxious or aggressive. • Separation from the mother at birth, as well as the mother’s own post-trauma stress response, can affect the early bonding between the mother and child, which is another major factor in the child’s psychological development.
Jim Carrey’s son Evan who is autistic.
• Negative experiences within family members and friends can have a huge impact. It affects the ability to cope and tendency to become mentally ill. • Mental illness can be triggered by a traumatic life event or situation and/or prolonged stress. Some examples are as follows: o Lack of support from relationships o Child abuse and neglect o Family violence o Severe or prolonged stress o Unemployment o Major changes in life
Psychological and Social Factors
Drugs & Alcohol
• Illicit drugs have the ability to stimulate particular parts of the brain which can affect development in adolescence. • Cannabis has been found to worsen depression and lessen an individual's motivation. • Alcohol damages "white matter" in the brain which affects thinking and memory.
• Oxford Textbook of Psychiatry • The Medical Basis of Psychiatry, 3rd edition • U.S. Surgeon General Releases Advisory on Alcohol Use in Pregnancy. United States Department of Health and Human Services. Press release (February 21, 2005). • The Effect of In Utero Maternal Distress on the Neurodevelopment of the Fetus, NFH • Genetic factors and mental disorders, Encyclopedia of Mental disorders • What are the Causes of Mental Illness?, The Kim Foundation