Some medications, especially those which affect the serotonin system, have been found to alleviate symptoms of OCD. These can only be prescribed by a medical practitioner. These antidepressants are not addictive, but some people may experience side-effects so careful supervision is needed. Side effects may include nausea, headaches, dry mouth, blurred vision, dizziness and feeling sleepy. These effects often dissipate after the first few weeks of treatment. If you are concerned about side effects which are severe or last for a long time discuss this with your doctor. A change in dosage or a change of medication may solve the problem. To be effectively trialled the medication needs to be taken for an adequate amount of time and at the right dosage level. Responses to the medicine usually takes several weeks, and improvements may continue during the following months of treatment. When stopping treatment the dose should be reduced slowly.