There are two main characteristic symptoms of OCD: obsessive thoughts and compulsive behaviors. The obsessive thoughts are negative and difficult to impossible to control. They may include things like a fear of germs or contamination, thoughts of loved ones being harmed, taboo or sexual thoughts, or fears of having forgotten to do something.
These thoughts are difficult to shake and cause a great deal of distress. They trigger obsessive behaviors that are equally difficult to control. Examples of compulsions include excessive hand washing, rearranging and ordering objects, repeatedly checking something, like a door lock, or tapping or touching objects in a certain patterns. The obsessions and compulsions vary by individual and are often related to each other, but do not have to be.
To be diagnosed with OCD a person has to have obsessions or compulsions, but most people experience both. A lot of people experience some degree of obsessive thoughts and ritualized, compulsive behaviors, but those with OCD spend a significant amount of time and energy on them. They cause a lot of distress and impairment in one or more areas of life.
Substance use disorders that may accompany OCD can worsen the symptoms of the condition, even though an individual is using in order to get relief. A person may be diagnosed with a mild, moderate, or severe substance use disorder, based on how well they meet the criteria: being unable to control use of the substance, experiencing social impairment, using substances in spite of risks and harm, and experiencing tolerance and withdrawal.
Diagnosing co-occurring disorders can be difficult because the two conditions affect each other. It is also important but often challenging to distinguish between true OCD and symptoms triggered by substance use. Because the two often occur together, it is important for patients with one of these conditions be screened for the other.