10 Types of Medications That Can Make You Feel Depressed

For example, levodopa, the most commonly prescribed Parkinson's medication, is converted into dopamine on entering the brain; it's typically combined with carbidopa, which helps prevent it from breaking down before it can reach the brain and take effect, in brand-name products such as Atamet, Sinemet and Stalevo.

Another approach is the use of dopamine agonists such as pramipexole (Mirapex) and ropinorole (Requip), which work by stimulating the dopamine receptors in the brain, thus mimicking the activity of dopamine.

How they can cause depression: Dopamine is one of three basic neurotransmitters that have been associated with depression (the others are serotonin and norepinephrine). Researchers believe that prolonged exposure to higher levels of dopamine may cause depression.

Alternatives: As many as 25 percent of all patients who are diagnosed with Parkinson's don't actually have the disease, so it's important to make sure that you're not among those misdiagnosed. Older people with essential tremors — involuntary trembling or quivering of the hands, limbs or other parts of the body — are often misdiagnosed as having Parkinson's. There's also drug-induced Parkinson's, which can often be reversed if the offending medication is discontinued early enough. (Older patients, for example, frequently develop parkinsonism after being prescribed antipsychotic drugs such as Haldol, Mellaril, Stelazine and Thorazine.) A systemic neurological examination is the best way to test for Parkinson's disease. And if you need to take levodopa, the dose can be reduced with the use of a COMT-inhibitor, a relatively new type of drug that blocks an enzyme in the body from metabolizing the levodopa before it reaches the brain.

5. Hormone-altering drugs

Why they're prescribed: Hormone-altering drugs are used to treat a variety of conditions. Estrogen (Premarin), for example, is typically prescribed for hot flashes and other postmenopausal symptoms .

How they can cause depression: Manipulating hormone levels in the body can cause a variety of problems, particularly as medications interact with the central nervous system. Studies show that changes in hormonal levels are significantly associated with the appearance of symptoms of depression.

Alternatives: Once again, it's important to try to identify the cause of the symptoms. Review the medications you're taking — prescription and over the counter — with your doctor to identify some problems that can be corrected without additional drugs.

6. Stimulants

Why they're prescribed: Stimulant medications, such as methylphenidate (Ritalin) and modafinil (Provigil), are often prescribed to treat excessive daytime sleepiness, whether caused by hypersomnia, narcolepsy or sleep apnea. They're also prescribed for ADHD and fatigue.

How they can cause depression: Stimulant medications increase the level of dopamine in the body. Researchers believe that prolonged exposure to higher levels of dopamine may cause depression.

Alternatives: As with insomnia (see benzodiazepine hypnotics, above), it's important to identify the cause of excessive daytime sleepiness. Other medications you're taking — whether prescription or over the counter — could be responsible. Drugs with sedating effects, for example, are among the most common causes of excessive daytime sleepiness. (These include alpha- and beta-blockers, anti-diarrheal agents, antihistamines, antipsychotics, antispasmodics, cough suppressants, epilepsy drugs, skeletal muscle relaxants, Parkinson's drugs and some antidepressant medications.)

Nondrug causes of excessive daytime sleepiness include sleep deprivation, obstructive sleep apnea (when the throat muscles intermittently relax and block the airway during sleep) and depression. When such underlying conditions are treated appropriately, there's rarely, if ever, any need for the use of stimulants.

7. Anticonvulsants

Why they're prescribed: Anticonvulsant drugs, which have long been used to treat seizures, are increasingly being used to treat other medical conditions, including neuropathic pain, bipolar disorder, mood disorders and mania. Examples: carbamazepine (Tegretol), gabapentin (Neurontin), lamotrigine (Lamictal), pregabalin (Lyrica) and topiramate (Topamax).

How they can cause depression: Anticonvulsants are believed to work by affecting neurotransmitters, which act as chemical messengers in the brain. They may, for example, limit seizures from spreading by blocking the flow of signals from the central nervous system (CNS) rather than raise the threshold for seizures. All CNS depressants, including anticonvulsants, can cause depression.

Alternatives: For seizures, phenytoin (Dilantin), which raises the seizure threshold; for chronic neuropathic pain, venlafaxine (Effexor), which affects the two neurotransmitters, serotonin and norepinephrine, that are thought to play roles in regulating pain.

8. Proton pump inhibitors and H2 blockers

Why they're prescribed: Doctors typically prescribe these medications, which suppress the secretion of gastric acid, to treat gastroesophageal reflux disease (GERD).

How they can cause depression: While these drugs are known to cause depression, scientists don't yet understand why they do. When any major body process is blocked, however, the body often rebels in an intense effort to fight back. Consequently, it's altogether likely that changing the pH of the stomach could bring on changes to the central nervous system and the brain.

Alternatives: Know which foods trigger your acid reflux (spicy or fried foods, for example) and avoid them, especially in the hours before bedtime. A non-calcium-carbonate-based antacid, such as Mylanta, may also help. Many of my patients have reported relief from the home remedy of apple cider vinegar and honey (typically one tablespoon each, taken together), though I know of no scientific research that confirms the effectiveness of this approach.

9. Statins and other lipid-lowering drugs

Why they're prescribed: Statins are the class of drugs most commonly prescribed to lower cholesterol levels, followed by fibrates and other drugs, such as ezetimibe, colesevelam and nicotinic acid.

How they can cause depression: Recent research suggests that lipid-lowering drugs may cause depression by depleting levels of cholesterol in the brain, where it plays an important role in the release of neurotransmitters.

Alternatives: A combination of vitamin B12 (injectable or sublingual), vitamin B6, folic acid and fish oil can lower homocysteine levels in the body. Homocysteine, an amino acid, inflicts damage to the inner arterial lining (endothelium) and other cells of the body, elevating lipids levels. While there are many studies that substantiate this nondrug approach and many that reject it, I've found that it works consistently well in older patients without posing the risk of serious side effects.

10. Anticholinergic drugs used to treat stomach cramps and other GI disorders

Why they're prescribed: Anticholinergic medications slow the action of the intestine, thereby reducing the amount of stomach acid produced. They do this mostly by blocking the effects of acetylcholine, the neurotransmitter that causes muscles — including those in the intestine — to contract. Dicyclomine (Bentyl), for example, is widely used to treat the symptoms of irritable bowel syndrome.

How they can cause depression: Anticholinergics, as central nervous system depressants, can cause depression, sedation and cognitive impairment in older patients.

Alternatives:  Using an H2 blocker such as ranitidine (Zantac) in the lower-dose formulation (75mg) can work well for the occasional attack of heartburn and acid indigestion. A calcium-free antacid (Gelusil or Mylanta, for example) may help.