Drug and alcohol use or abuse can potentially have a devastating effect on your domestic case. If you are a litigant or potential litigant, there are some things that you should know.
First of all, judges in Missouri almost will always consider drug and alcohol use when making their decisions, particularly if children are involved. The amount of weight that it carries depends on the credibility of the evidence, the type of drug, the frequency of use, the history of use, and other factors.
Second, the court can order drug testing on its own motion, by motion of the other party, the Guardian ad Litem, or any other party to the case. If a motion is made, the court will usually grant the motion and require drug testing. If you are clean, this can actually work in your favor to some extent, but if not, there are going to be problems. And remember - legal problems are expensive - in more ways than one.
Third, as a litigant, you should always know that you are under the microscope and anything that you do has a not so funny way of turning up. With drugs and alcohol, you have everything to lose if that evidence comes in. If drug presence is found by testing, not only is there evidence against you, but you look like a complete idiot for allowing drugs to be detected in the first place when you know you have a case pending. Don't be that person.
Fourth, there are many types of drug tests that can be conducted, and they can be ordered at random, reducing the possibility that the test may be tampered with or the results altered using commercially available products. Testing may include urinalysis, blood, saliva, or hair follicle. Drugs can be detected between 2 days and 3 months, depending on the type of drug and the type of test. And by the way, hair doesn't just grow on the head.
Fifth, don't blow your case over this. What you choose to do is what you choose to do, but anywhere in the vicinity of a domestic or custody case is certainly not the time.