The monoamine theory is an important theory in helping us to understand some of the contributing factors that may lead to mental illness. This theory point towards the role neurotransmitters play in mental disorders. Serotonin, norepinephrine, and dopamine seem to play a role in several mental disorders, such as depression and schizophrenia. For example, an overabundance of dopamine has been linked to symptoms of schizophrenia, while a deficit of serotonin and norepinephrine may contribute to symptoms of depression. Therefore, medications which reduce the overabundance of dopamine in patients with schizophrenia tend to improve symptoms of schizophrenia in these patients. Likewise, medications which increase the presence of serotonin or norepinephrine may improve symptoms of depression.
However, the monoamine theory is unable to fully account for all symptoms of mental disorders. Some medications which do not seem to affect monoamines have been found to be beneficial in treatment of mental disorders. For example, lithium which is used to treat bipolar disorder, as well as unipolar depression, does not consistently increase synaptic concentrations of monoamines. On the other hand, cocaine, which is a strong reuptake inhibitor of dopamine, does not offer any therapeutic benefit in treating depression.
Medications which increase or decrease neurotransmitters are not always effective in reducing symptoms of mental disorders. Other treatments, such as psychotherapy may be more effective in reducing symptoms of various mental disorders in some patients. Often, psychotherapy in conjunction with medications is more effective than medications alone. Other factors, such as environment, familial stability, or financial stability may affect mental health. Addressing these factors often reduces symptoms in most mental disorders, as well.
Although the monoamine theory is an important theory, and should be kept in mind when designing a treatment plan, it is not able to account for the cause of all mental disorders. Due to the complexity of mental disorders, mental health professionals should employ multiple approaches to the treatment of mental disorders.