Common side effects with tricyclic antidepressants are:

• drowsiness or tiredness
• a dry mouth
• blurred vision
• constipation or difficulty in passing urine
• fast heartbeat
• weight gain
• a slight tremor
• sexual problems for men (eg erectile dysfunction)

Tricyclics are not suitable for people with heart trouble and particular side effects for older people include:

• Confusion
• Slowness in starting and stopping passing water
• Faints and falls

Common side effects with the SSRIs are:

• nausea and vomiting
• indigestion
• diarrhoea
• constipation

Less commonly they can cause anxiety, confusion, headache, insomnia, shaking, dizziness, dry mouth and sexual problems.

Antidepressants can interact with other medications and it is vital to check with your doctor or pharmacist if you are taking any other kind of treatment, even over the counter or herbal medicines.

Antidepressants can slow down your reactions, so it's a good idea to hang up your car keys until you know how you react to the medication that you are taking. The same goes for using power tools or anything that requires dexterity and concentration.

Antidepressants are not tranquillisers and do not have the addictive effects of tranquillisers, however it is best to reduce taking them gradually, rather than coming to a sudden stop, because there can be withdrawal symptoms.

Some medication prescribed for physical conditions can actually cause depression. These include beta-blockers and other blood pressure medication, some heart drugs, steroids and sedatives, check with your doctor or pharmacist for details of known side effects for any medication that you are taking.