Unlike many physical disorders, determining the cause of mental health disorders is not easy. For one thing, each psychological disorder has its own causes. Secondly, psychological disorders rarely ever appear for just one reason. Instead, mental health disorders typically arise from an interaction between biological, psychological and social factors.
Biological Factors
A number of biological factors may cause--or at least play a role in causing--mental health disorders. According to psychologists David Sue, Derald Sue and Stanley Sue, authors of "Understanding Abnormal Behavior," one key factor is genetics. Certain disorders occur most often when there is a family history of the disorder, such as schizophrenia and bipolar disorder. Another factor is brain chemistry. Between each of the nerve cells of the brain, called neurons, there is a small gap called a synapse. To communicate with one another, neurons must send chemical messengers over the synapse. If there is too little or too much of any of these chemical messengers, called neurotransmitters, a psychological disorder may result. For example, serotonin levels are typically too low in a person with major depressive disorder. Other causal biological factors include damage to the brain due to disease or an accident or problems in the endocrine system, which controls hormones in the body, says Sue and colleagues.
Psychological and Social Factors
Many theories exist about how psychological and social factors might cause mental health disorders. Some psychologists point to thoughts--or cognitions--as a root cause, according to Eric Mash and David Wolfe, authors of "Abnormal Child Psychology." If a person is having thoughts that are out of touch with reality and are immediate and unquestioned, he might develop a disorder. For example, thinking things like "everyone hates me" when there is evidence to the contrary, might contribute to depression. In addition, the rewards and punishments we get for our behaviors might play a role in causing a mental health disorder. For example, children are typically punished for acting rudely and rewarded with social praise for acting politely. If a child instead experiences the reverse, such as getting attention for rude behavior and being ignored when polite, she might develop oppositional defiant disorder.
Major Stressor
Many people jump right to biological causes when discussing the origin of mental health disorders. In fact, though, biology alone typically does not explain the appearance of a disorder. Although genetics may play a causal role in mental disorders, even identical twins often fail to have the same disorder. It seems that both a genetic vulnerability AND exposure to a major stressor are needed to trigger development of a disorder, say Sue and colleagues. What exactly constitutes "a major stressor" varies from person to person, depending on how well they know how to cope with stress. For instance, for one person with a family history of schizophrenia, everyday college stressors may cause the disease to appear. For another, it might take the death of a parent to be "too much." Psychologists call this the diathesis-stress model of mental disorders.
References
- "Understanding Abnormal Behavior"; David Sue, Derald Sue, and Stanley Sue; 2008
- "Abnormal Child Psychology"; Eric Mash and David Wolfe; 2004
- National Institutes of Health: Mental Health
