The SHU, or Special Housing Unit, strips away most of what makes daily life manageable, but it does not eliminate all contact with the outside world.
Mail continues to reach SHU inmates. That is one of the few privileges that survives a SHU placement largely intact, which makes letters and photos one of the most meaningful things you can send during this period. InmateAid can get a letter to your person without your home address on the envelope, and having something arrive in that environment matters more than it does in general population.
Phone access is severely restricted. The standard allowance is one 15-minute call per week. That window is limited and the timing depends on when staff facilitates it, so missed connections can mean waiting another full week for the next opportunity. Make sure you are available and reachable when calls are possible.
Visitation in the SHU is limited but sometimes permitted depending on the facility and the reason for placement. Where visits do occur they are typically non-contact, meaning a glass partition or screen rather than the open visiting room experience. Some facilities suspend visitation entirely during SHU placement.
On the mental health question, the research is clear and unambiguous. Solitary confinement causes genuine psychological harm, particularly over extended periods. Anxiety, depression, hypersensitivity to stimuli, distorted thinking, and in serious cases symptoms resembling psychosis are all documented consequences of prolonged isolation. The experience of every minute feeling like an hour is real and it accumulates.
If your person is in the SHU, staying connected through letters is the most consistent lifeline available. Keep writing regardless of whether responses come back quickly.