Psychoactive drugs have also been important tools in the treatment of mood disorders such as Major Depressive Disorder and Bipolar Disorder as well. For a major depressive episode, the essential characteristics of such a mental disturbance include a depressed mood for more than two weeks’ duration in which there is a pronounced loss of interest or enjoyment in activities that a person once regularly found enjoyment and engaged in. In addition, it is quite common for people to experience feelings of worthlessness and hopelessness, a loss or increase in appetite with commensurate weight loss or excessive gain, fatigue or loss of energy, insomnia or bouts of excessive sleeping, problems concentrating and possible suicidal ideation.
Given the reported incidents of sleep disturbance in this clinical population, when coupled with the increased risk for suicidal ideation, it is important that a prescribing physician not consider a barbiturate drug for the treatment of any reported sleep disturbance. As you have learned from previous week’s material, the risk of combining a barbiturate with alcohol into a lethal combination presents too significant of a risk and individual who may be suicidal.
What is the prevailing neurochemical theory of depression? How is it treated with drugs?
To begin, review this quick 4-minute video from ASAPScience.com for an overview of the physiological processes:
When left untreated, major depressive disorders can last for six months’ duration or longer but, eventually, most individuals return to a premorbid state of functioning, regardless of treatment. The disorder appears to be more common in females than males with a ratio of approximately 2:1. The most prominent neurochemical theory that serves to explain the presence of depression in individuals is that of the catecholamine hypothesis. It views symptoms of depression as being due to a deficiency in the neurotransmitter norepinephrine and, possibly, serotonin. This hypothesis is supported, in part, by research which demonstrates that drugs which increase norepinephrine at the neural receptor sites also seem to concurrently help alleviate symptoms of depression. Conversely, when depressed individuals are given medications that decrease the amount of norepinephrine at the neural receptor sites, more severe symptoms of depression are elicited. Other neurotransmitters have also been implicated in the manifestation of depression, including acetylcholine, dopamine, and GABA.
Three classes of antidepressant drugs are available to treat mood disorders. This includes tricyclics (TCAs), heterocyclic antidepressants (HCAs) and monoamine oxidase inhibitors (MAOIs). It has been estimated that somewhere between 60 and 70% of individuals who are prescribed one of these classes of drugs respond positively in terms of a lessening of depressive symptomatology when compared to a course of placebo. Tricyclic antidepressants seem to be most effective for addressing what would be considered the most characteristic or “classic” symptoms of depression (e.g., sadness, loss of interest in activities), experience a worsening of symptoms in the morning, and self-reported symptoms of mild to moderate severity.
In contrast, monoamine oxidase inhibitors seem to be most beneficial for individuals who have atypical symptoms associated with their depression, including phobias and anxieties and a mood that worsens late in the day. Regardless of medication that is chosen, it is quite typical for an individual to take these antidepressant drugs for several months until their symptoms have sufficiently resolved. It often requires several weeks of consistently taking one of these classes of medications before the individual reports a therapeutic effect.
How is depression different from bipolar disorder? How does the drug treatment differ?