Though some terminal illnesses may seem to make people choose death over life, god put you on Earth for a reason. Besides that, nobody should be able to take their whole life and destroy their existence when they aren't in their right mind. Pain makes people do some extreme things, but it shouldn't include death.
Although an argument can be made for permitting assisted suicide in some instances, the unrestricted availability of this activity is unwise. Although a person with a painful, incurable illness may truly be without any real hope, many individuals that face the prospect of suicide actually possess other and more appropriate options. Permitting unbridled access to assisted suicide impairs the ability of individuals to seek out and utilize these more appropriate options.
Yes, assisted suicide should be illegal for children and adults who have a diminished capacity to understand the proceedings. Children have not reached an age where they can understand the implications of this life-ending decision. Some adults also are incapable of understanding assisted suicide, either because of mental deficiencies or because the illness affects their cognition. It is unfair to make such a weighty decision for children or adults in this situation.
As devastating as suicide is, every individual should be able to complete this final act with or without help as needed to retain their personal dignity or to escape suffering. People with health conditions may not be able to commit suicide on their own, so they should be able to receive help when necessary.
While suicide should not be the answer in most cases, some situations make living life almost impossible to live each day. For example, if a person is in severe chronic pain each and every day so bad that they do not want to live anymore, and medications and therapy have not helped, they should be given the right to take their lives if they so choose.