People who do not have the benefit of professional diagnosis and care run two risks when they try to diagnose and treat themselves using self-help methods:
Risk of Misdiagnoses. The first risk is that they might miss something subtle but important about their problem or issues which would, in turn, cause them to misdiagnose themselves, possibly with disastrous results. For example, someone might think they have an anxiety condition of some sort, but closer professional examination might uncover an underlying serious medical problem such as an heart arrhythmia The affected person might treat themselves as though they have an uncomplicated anxiety problem (e.g., with relaxation exercises) and completely miss the fact that they have a serious medical condition that requires medical treatment. There is really no good way to reduce this type of risk except to go to a professional for a professional diagnosis.
Risk of Wrong Treatment. The second risk inherent in self-diagnosis and self-treatment is that people might end up treating themselves with methods that don't work at all, which are inefficient, which are plain old wrong for their problems, or which actually cause harm. This risk is heightened when treatments and methods that people consider using are inherently dangerous when misused. For example, someone might try to treat their weight problem with with pills that were prescribed for someone else, or illegally obtained on the street. They might alternatively decide that the best way to lose weight is to starve themselves by fasting (not a good idea at all!) or by engaging in strenuous physical workouts on a regular basis. Research shows that starving yourself is unlikely to result in any weight loss, and may cause other problems to develop, including binge eating patterns which can lead to eating disorders like Bullemia. A non-health-professional person might not know this important fact and starve themselves anyway. Similarly, strenuous exercise might be appropriate and even healthy for some people, but it might provoke a heart attack in someone else (in a worst case scenario), or simply lead to pain and "Charley horse" that would discourage them from pursuing further healthier methods for weight loss.
It is never a good idea to take someone else's pills, by the way, and never a good idea to treat a problem with street drugs! Weight loss pills can be habit forming, for one thing, and may lead to an addiction. They can also cause medical problems. Medication might be safe for another person, but actually dangerous for you! Do not use medication except under the supervision of a licensed physician or other appropriate health professional.