Service dogs are trained to assist individuals with disabilities by performing tasks to mitigate the effects of their disabilities. Guide dogs help blind or visually impaired individuals navigate and alert deaf individuals to sounds in their environment. Service dogs can also retrieve dropped items, wake individuals from sleep, and remind owners to take medication for psychiatric disabilities like depression. Effective service dogs possess traits like alertness, energy, and an ability to focus on their owner. While expensive to purchase fully trained, individuals can also work with experienced trainers to teach adopted dogs disability-specific tasks.