Substance-Induced Mood Disorder
The use and abuse of certain medications, street drugs and/or alcohol can lead to classic symptoms of depression. Conversely, a depressed mood or sense of hopelessness can also lead to a vicious cycle of substance use. Often, people who feel down "self-medicate" in order to make the pain of their depressive moods disappear; however, this often leads to substance binges and addiction, which can make people's moods and self-esteem even lower. Mood symptoms can occur during the use of and withdrawal from alcohol, amphetamines (stimulating drugs such as cocaine), hallucinogens (drugs that affect perceptions, sensations, thinking, self-awareness, and emotions, such as LSD), and sedatives/hypnotics/anxiolytics (calming drugs used to treat anxiety such as Valium or Xanax).
Sometimes, depression is caused by medications that are being used to treat or control other medical conditions. Pain relievers such as morphine, anticholinergics (used for gastrointestinal cramps, bladder spasms, asthma, motion sickness, and muscular spasms), anticonvulsants (used to control seizures), antihypertensives (used to control high blood pressure), antiparkinsonian medications (used for Parkinson's disease), anti-ulcer medications, cardiac medications (used for heart disease), oral contraceptives (birth control pills), antidepressants (used to treat depression), antipsychotics (used to treat psychotic symptoms), muscle relaxants, steroids (such as Prednisone; used to decrease inflammation), and antibiotics such as sulfonamides (used for infections) can all cause depressive symptoms. In addition, heavy metals and toxins such as gasoline, paint, insecticides, nerve gases, carbon monoxide and carbon dioxide may also cause mood symptoms (See our later section on Environmental Causes of Depression).
The DSM-IV-TR diagnostic criteria for Substance-Induced Mood Disorder require that the onset of a person's depressive symptoms occurs in the context of drug use, intoxication, or withdrawal. However, a person does not need to display each of the MDD symptoms in order to receive a Substance-Induced Mood Disorder diagnosis.
Approximately 60% of people with depression also experience symptoms of anxiety. For example, someone who worries excessively about their work may eventually become depressed because of their inability to control the things that worry them. An anxiety disorder is characterized by constant tension, nervous energy, and fatigue. Anxious people may also experience trembling, twitching, dry mouth, sweating, nausea, diarrhea, or a sensation of a lump in the throat. In panic disorder (a specific type of anxiety disorder), individuals experience a sudden wave of frightening physical sensations and emotional symptoms which include a racing heartbeat, shaking, sweating palms, a heaviness or pain in the chest, lightheadedness, numbness or tingling sensations, and/or shortness of breath. An intense feeling of dread or doom takes over, and people frequently think they are having a heart attack.
In about 1/3 of people, depressive symptoms develop first (before an anxiety disorder); however, depression can also come about after or co-occur with the development of an anxiety disorder. Many times, treating symptoms of depression will also alleviate symptoms of anxiety as well. Typically, the best treatment strategy for a combination of anxiety and depressive symptoms is a mixture of medication and psychotherapy. (For more information on Anxiety Disorders, click here to read our article).
Seasonal Affective Disorder (SAD)
When the winter months hit and daylight grows shorter, some people start feeling a little sluggish, experience a bit of weight gain, have difficulty getting out of bed, and have bouts of "the blues". Symptoms begin in the fall, peak in the winter and usually resolve in the spring. The typical symptoms of SAD include low mood, lack of energy, changes in appetite and sleep, feelings of guilt and self-blame, and hopelessness - in short, the whole syndrome of depression. According to the DSM, SAD is classified as a depressive pattern specifier; so it is a variation on the theme of regular Major Depression and not something unique or separate from Major Depression. SAD is not considered a disorder or syndrome on its own.
Most people with SAD experience relatively mild symptoms, but others have more debilitating symptoms that cause their interpersonal relationships and work to suffer. Although SAD may be a temporary form of depression, it may occur with the full intensity and force of a Major Depressive Episode and should be treated as such. If SAD symptoms are mild, no treatment may be necessary. However, if symptoms are problematic, medication or psychotherapy can be indicated.
Light Therapy is another effective treatment for SAD. The seasonal incidence of SAD occurs in relationship to the rising and falling periods of daylight available across the year. The daylight period is shortest during the winter months, at exactly the time when SAD is peaking. SAD goes away as the daylight period becomes extended during the summer months.
In light therapy, SAD patients are instructed to sit for extended periods of time in front of a very bright light source during the early morning hours. The light source replaces the daylight missing during the winter months, and helps to approximate summer light conditions. Many SAD patients find that their mood improves with this treatment. However, it remains unclear whether light therapy works as well as antidepressant medications, or whether cognitive behavioral therapy is a better treatment choice.