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Antidepressant Medication Centre for Addiction
and Mental Health

 Health Info A-Z


Antidepressant Medication

Wh​at are antidepressants? 

Antidepressant medications are most commonly used to help relieve the distress of depression or anxiety. They are also used to help with other conditions, such as bulimia and chronic pain. 

These medications help many people with mental health problems. However, they don’t work for everyone, and even when they do work well, they can only do so much. They often work best when they are combined with talk therapy, support from family and friends, and self-care, such as regular exercise, a nutritious diet and getting enough sleep. Learning how to live well in spite of your distress is also important. 

Antidepressant medications can take up to several weeks to be fully effective. Early signs that the medication is working include improved sleep, appetite and energy. Improvement in mood usually comes later. 

Do I need treat​​ment?

We all experience depression and anxiety at some level, and because of this, severe problems are sometimes trivialized. People who are severely depressed or anxious for a long time may feel they should be able to shake it off, and so don’t seek treatment. Some people live this way for years. 

If you are distressed for more than two weeks by feelings of sadness, despair and hopelessness, or by excessive worry that is hard to control, see a doctor for an assessment of your symptoms and situation and to discuss treatment and support options. Many people who are treated for depression or anxiety recover and never require treatment again. Early treatment can help to ensure treatment success. 

Be sure your doctor knows if you have had times where you felt a reduced need for sleep in combination with an unusual amount of energy, or where your mood changed from feeling depressed to feeling unusually happy or irritable. Antidepressants can cause some people to switch from depression into mania. Mood stabilizer medications may be more suited to your needs, either on their own or in combination with antidepressants.

Medications are only one way of treating depression and anxiety; talk therapies, such as interpersonal therapy and cognitive-behavioural therapy can be just as effective. Depression and anxiety are often a signal that change is needed. These psychological approaches may help you to make the changes you need to make in your life. Peer support, school and job counselling and housing and employment supports can also help to deal with problems that may trigger or worsen depression or anxiety. 

What do antidepres​sants do? 

Antidepressant medications increase the activity of certain chemicals, known as neurotransmitters, in the brain. Increasing the activity of the neurotransmitters serotonin, norepinephrine and dopamine seems to help lessen depression and anxiety. However, the brain is a very complex organ and the reasons why these drugs work are not yet fully understood. 

We do know that these drugs help to relieve symptoms of depression and anxiety in up to 70 per cent of people who try them. This rate is even higher when people who don’t get relief with one type of antidepressant try a second type. 

Do antidepressants have side-effects? 

All medications can have side-effects. Some people experience no side-effects. Others may find the side-effects distressing. In most cases, side-effects lessen as treatment continues. 

Treatment is usually started at a low dose, to minimize side-effects, and then slowly increased until the ideal dose is found. The ideal dose is one that provides the greatest benefit with minimum side-effects.

One of the main reasons why people stop taking these medications is the side-effects. Check the information given to you by your doctor or pharmacist on the specific effects of any drug you have been prescribed. If side-effects are not mild and tolerable, it is best to continue taking your medication as prescribed and let your doctor know as soon as possible. Your doctor may: 

    • encourage you to wait a little longer for the side-effects to fade
    • adjust your dose 
    • you take the medication at a different time of day
    • prescribe other medications to help control side-effects
    • ​change your medication
    • stop medication treatment and suggest a different type of treatment approach.

    Side-effects vary depending on the type of medication. More information on side-effects is included for each type of types of antidepressant.

    Do antidepressants​ increase the ris​k of suicide?

    One of the symptoms of depression is suicidal thought and​ behaviour. When starting medication treatment for depression, people may be at an increased risk of suicide. One possible explanation is that it may be related to the increase in energy that comes early in treatment, before improvement in mood. In other words, antidepressants may give some people the energy to act on their suicidal thoughts.

    Antidepressants can also cause feelings of agitation, restlessness and detachment. These feelings may resemble symptoms of anxiety and may add to, rather than relieve, feelings of hopelessness and despair. Some people may become suicidal or violent. This reaction to antidepressants is thought to occur in about four per cent of people who take them, with the risk being highest in the first few weeks of treatment. 

    Before starting treatment, it is important to prepare for the possibility of feeling worse before you feel better. Know what supports are available to you and who you can call. When you begin treatment, monitor your thoughts and moods, and communicate any thoughts of hurting yourself or others with your doctor, a crisis line or the emergency department. 

    If you experience an increase in suicidal thinking or anxiety, your doctor can help you decide if you should stop taking the medication or if you should try to be patient and give the medication a chance to work.  ​​

    What are the different types of anti​depressant medications?

    • SRIs—selective serotonin reuptake inhibitors
    • SNRIs—serotonin and norepinephrine reuptake inhibitors
    • NDRIs—norepinephrine and dopamine reuptake inhibitors
    • NaSSAs—noradrenergic and specific serotonergic antidepressants
    • Cyclics
    • MAOIs—monoamine oxidase inhibitors

    There are several classes of antidepressants; within each class there are  many    individual medications. While all antidepressants work well overall, no drug or  type of  drug works equally well for everyone who takes it. You may be advised to try  more than  one type of antidepressant or to use a combination of antidepressants to  seek relief  from your distress. ​

    The different types of antidepressants are listed below in the order in which they are  most commonly prescribed.

    SSRIs—selective serotonin reuptake ​​inhibitors

    This group of drugs, including fluoxetine (Prozac), paroxetine (Paxil), fluvoxamine (Luvox), citalopram (Celexa), escitalopram (Cipralex) and sertraline (Zoloft), is usually the first choice for treatment of depression and anxiety problems. These medications are known to have milder side-effects than some other antidepressants. Buspirone (Buspar) is similar to SSRIs and has been found to help with anxiety but not depression.

    Common side-effects include nausea, vomiting, diarrhea, weight gain, dry mouth, headaches, anxiety, sedation and a decrease in sexual desire and response. This group of drugs may also cause a jittery or restless feeling and sleep difficulties, such as problems falling asleep, waking in the night, vivid dreams or nightmares. 

    SNRIs—serotonin and norepinephr​​ine reuptake inhibitors

    This class of medications includes venlafaxine (Effexor), duloxetine (Cymbalta) and desvenlafaxine (Pristiq). These drugs are used to treat depression, anxiety problems and chronic pain. 

    Common side-effects include nausea, drowsiness, dizziness, nervousness or anxiety, fatigue, loss of appetite and sexual problems. In higher dosage, these medications may increase blood pressure. 

    NDRIs—norepinephrine and dopamine ​​reuptake inhibitors

    The medication available in this class is bupropion (Wellbutrin, Zyban). When used to treat depression, it is often given for its energizing effects, in combination with other antidepressants. It is also used to treat attention-deficit/hyperactivity disorder and as a smoking cessation aid.

    Common side-effects are jitteriness and insomnia. 

    NaSSAs—noradrenergic and specific sero​​tonergic antidepressants

    Mirtazapine (Remeron), the medication available in this class, is the most sedating antidepressant, making it a good choice for people who have insomnia or who are very anxious. This medication also helps to stimulate appetite. 

    Common side-effects are drowsiness and weight gain. 


    This older group includes amitriptyline (Elavil), maprotiline (Ludiomil), imipramine (Tofranil), desipramine (Norpramin), nortriptyline (Novo-Nortriptyline) and clomipramine (Anafranil).

    Because these drugs tend to have more side-effects than the newer drugs, they are not often a first choice for treatment. However, when other drugs do not provide relief from severe depression, these drugs may help. 

    Common side-effects include dry mouth, tremors, constipation, sedation, blurred vision, difficulty urinating, weight gain and dizziness. Because cyclics may cause heart rhythm abnormalities, your doctor should give you an electrocardiogram (ECG) before you take this medication. 

    Monoamine oxidase i​​nhibitors

    Monoamine oxidase inhibitors, or MAOIs, such as phenelzine (Nardil) and tranylcypromine (Parnate) were the first class of antidepressants. MAOIs are effective, but they are not often used because people who take them must follow a special diet.

    A newer MAOI, moclobemide (Manerix), can be used without dietary restrictions; however, it may not be as effective as other MAOIs.

    Common side-effects include a change of blood pressure when moving from a sitting to a standing position (orthostatic hypotension), insomnia, swelling and weight gain.

    Controlling side-effec​​ts​

    You can help to control possible side-effects on your own by:

    • ​getting regular exercise and eating a low-fat, low-sugar, high-fibre diet (e.g., bran, fruits and vegetables) to help prevent weight gain and constipation
    • using sugarless candy or gum, drinking water and brushing your teeth regularly to increase salivation and ease dry mouth
    • getting up slowly from a sitting or lying position to help prevent dizziness. 


    * Medications are referred to in two ways: by their generic name and by their brand or trade names. Brand names available in Canada appear in brackets.

    How long should ​I take antidepressants?

    When you start a new antidepressant, the first step is to decide whether you can tolerate the side-effects; this should become clear within a few weeks. The next step is to decide whether the drug helps with your depression or anxiety; for this, you will need to take it at full dose for at least six weeks. 

    If the medication does work for you, your doctor will advise you to continue taking it for at least six months after you start to feel its beneficial effects. People who stop taking antidepressants too soon risk having the symptoms of their depression or anxiety problem return. Most people who take antidepressants need to take them for at least a year. People who experience depression that keeps coming back may need to take them for a longer term. 

    Are antidepressants addi​​ctive?

    Drugs that are addictive produce a feeling of euphoria, a strong desire to continue using the drug, and a need to increase the amount used to achieve the same effect. Antidepressants do not have these effects.  

    Antidepressants do, however, have one thing in common with some addictive drugs—they can cause withdrawal effects when you stop taking them. When you take antidepressants for months or years, your body adjusts to the presence of the drug. If you then stop using it, especially if you stop suddenly, you may experience withdrawal effects such as muscle aches, electric-shock-like sensations, dizziness, headache, nausea, chills and diarrhea. These effects are most commonly reported with paroxetine (Paxil) and venlafaxine (Effexor); however, they can occur with any antidepressant. Some people find these effects distressing and have difficulty withdrawing from these drugs.

    How do I cut down or stop taking ant​idepressants?

    Whether you want to cut down your dose or stop taking a medication, the same rule applies: go slowly. Sudden changes in your dose can greatly increase your risk of having another mood episode.  

    The first step is to ask yourself if this is the right time. Are you feeling well? Is the level of stress in your life manageable? Do you feel supported by your family and friends?  

    If you think you’re ready, talk to your doctor. If your doctor doesn’t agree, find out why. If you are not satisfied with his or her reasons, you may want to see another doctor for a second opinion.  

    If your doctor does agree, he or she will advise you not to skip doses but to reduce your dose gradually—usually by about 10 per cent at a time—with at least two to three weeks between each reduction. This process of cutting back will take several months. Using a pill cutter can help you to cut your dose down in small amounts.  

    If you want to stop taking more than one medication, your doctor will usually suggest that you lower the dose of one drug at a time.  

    As you cut down, if you start to feel unwell, let your doctor know. He or she can help you determine whether you are experiencing withdrawal effects or signs that symptoms are returning. Don’t be afraid to go back up with your dose. Find the dose that works best for you.     

    Will antidepressants interact with ot​her medications? 

    Antidepressants may interact with some other types of medication, even over-the-counter medications, such as cold or allergy tablets or cough syrups, and some herbal remedies, such as St. John’s wort. Always ask your doctor, dentist or pharmacist about potential drug interactions with the medication you are taking before you take other medications.  

    What if I drink alcohol or coffee while t​aking antidepressants?

     Drinking alcohol can worsen symptoms of depression or anxiety. Alcohol can also worsen some side-effects of antidepressants, making you more sleepy, dizzy and lightheaded. However, if you have been taking antidepressants for more than a few weeks, and you are feeling well, having a drink or two on occasion should be okay—but remember that one drink could have the effect of two or even three drinks.  

    The caffeine in coffee and other beverages can cause problems if you struggle with depression or anxiety. Depression disrupts sleep and caffeine, a stimulant, can make the problem worse. It is better to drink decaffeinated coffee and beverages or to decrease the amount you drink. 

    What if I use street drugs while taking antidepressants? 

    If you’re taking antidepressants, chances are you’re trying to get relief from symptoms of depression or anxiety. You want to feel well. While street drugs such as marijuana or cocaine may have some effects that seem to make you feel better for a while, mixing the effects of these drugs with your symptoms may make your situation worse. Street drugs may also interact with your medication, for example, by interfering with its effectiveness or by worsening side-effects.

    Will antidepressants affect my abili​ty to drive safely? 

    Depression itself can lead to fatigue and concentration problems, affecting your ability to drive. Antidepressant medications may also cause drowsiness, especially in the early stages of treatment, before your body has adjusted to the medication. If you feel drowsy, do not drive a car or operate machinery. Alcohol, sedatives and antihistamines (cold and hay fever medication) will worsen the problem. It’s never wise to drive after drinking alcohol, and it’s even more important to follow this rule when taking antidepressants. 

    Will antidepressants affect my se​​x drive and function? 

    Both depression and the drugs used to treat it can decrease people’s desire for sex. Antidepressants, especially those that increase serotonin activity, can also negatively affect sexual function. Sexual side-effects of antidepressants can include delayed ejaculation and the inability to experience an orgasm. 

    Many factors affect your sexuality. When antidepressants bring relief from the distress of depression or anxiety, this may help you to focus more on your partner and to feel more desire. If you think your medication affects your sexual function, your doctor may be able to help by changing your dose, switching medication or adding other medications.  

    Is it safe to take antidepressants while pr​egnant or breastfeeding? 

    Each woman’s situation is unique and should be discussed with her doctor. For any pregnant woman with a history of depression, the question of whether to take antidepressants during pregnancy usually comes down to a risk-benefit analysis. Depression can affect prenatal care and a mother’s ability to parent her newborn child. When treatment with an antidepressant helps to avoid a relapse or to reduce distress, the benefits of continuing the medication may outweigh the risks.  

    Antidepressants are relatively safe to use during pregnancy. When they are used close to delivery, newborns may be restless and irritable, and may have sleeping, feeding and breathing difficulties. These problems resolve within three days to two weeks. Antidepressants do not increase risk for birth defects.  

    The amount of antidepressant passed through breast milk is very small and is not considered to be a risk to the baby, especially when weighed against the benefits of breastfeeding.  

    If you decide to stop taking medications during pregnancy or while breastfeeding, it is a good idea to see your doctor more often, to help you monitor for a return of symptoms.

    Is age an issue when taking antidepre​​ssants? 

    The effectiveness and risks of an antidepressant can vary depending on the age of the person taking it. 

    Can children and teens use antidepressants?​ 

    Most antidepressants are not officially approved for use by children and teens. The first line of treatment with this age group should always focus on resolving issues in the young person’s life and on counselling. However, when distress is so severe that non-drug approaches are not possible, or when they do not work, antidepressants may be considered. Studies of children and youth who take antidepressants suggest an increased risk of suicidal thoughts and behaviour, but not death by suicide.  

    Can older adults use antidepr​essants? 

    Antidepressants are an effective treatment for depression in adults over 65 and are known to decrease the risk of suicide in this population. However, due to the increased sensitivity of the older body, older adults are more vulnerable to side-effects. As older adults often take multiple medications, they are also more vulnerable to drug interactions.

    Copyright @2009, 2012 Centre for Addiction and Mental Health​

    Where can I find help, treatment and suppor​t? 

    Treatment from CAMH

    Help for Families from CAMH

    Ontario Mental Health Helpline(open 24/7 for treatment anywhere in Ontario

    Support groups in your area: call 211 or check online at www.211Ontario.ca​​

    Where can I find m​ore information related to antidepressants?

    For more information on medications, contact your doctor, nurse or pharmacist.​​​​​​

    For information on using medications while pregnant or breastfeeding, contact MotherRisk at 416 813-6780 or visit www.motherisk.org.​

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