Its prevalence among men is 15.9%, while 18.9% of women experience it. When considering specific populations, 28.3% of students and 31.9% of psychiatric patients have experienced this phenomenon at least once in their lifetime. Of those psychiatric patients, 34.6% have panic disorder. Sleep paralysis in students is slightly more prevalent for those of Asian descent (39.9%) than other ethnicities (Hispanic: 34.5%, African descent: 31.4%, Caucasian 30.8%). Restless leg syndrome
According to one meta-analysis, the average prevalence rate for North America and Western Europe is estimated to be 14.5±8.0%. Specifically in the United States, the prevalence of restless leg syndrome is estimated to be between 5% and 15.7% when using strict diagnostic criteria. RLS is over 35% more prevalent in American women than their male counterparts. See also
References
External links

 Media related to Sleep disorders at Wikimedia Commons
Sleep Problems – information leaflet from mental health charity The Royal College of Psychiatrists
WebMD Sleep Disorders Health Center
Potassium iodide and silver nitrate are used to make silver(I) iodide, which is used for high speed photographic film and for cloud seeding:

  
    
      
        
          
            KI
            
              
                (
                aq
                )
              
            
            
              
            
          
          

          
          +
          9
          
          
            AgNO
            
              3
              
                (
                aq
                )
              
            
            
              
            
          
          ⟶
          
            AgI
            
              
                (
                s
                )
              
            
            
              
            
          
          

          
          +
          
            KNO
            
              3
              
                (
                aq
                )
              
            
            
              
            
          
        
      
    
    {\displaystyle {\ce {KI_{(aq)}{}+ 9AgNO3_{(aq)}-> AgI_{(s)}{}+ KNO3_{(aq)}}}}

Organic chemistry
KI serves as a source of iodide in organic synthesis.