SPD most commonly stands for Sensory Processing Disorder, a neurological condition that affects how the brain interprets information from the senses. But depending on context, SPD can also refer to Symphysis Pubis Dysfunction (a pregnancy-related pelvic condition), Schizoid Personality Disorder, or Social Pragmatic Communication Disorder. Here’s what each one means and how to tell which applies to you.
Sensory Processing Disorder
Sensory Processing Disorder is the most widely searched meaning of SPD. It describes a difference in how the brain receives and responds to sensory input: what you see, hear, smell, taste, and touch, as well as how you sense your body’s position and movement. Researchers estimate that 5 to 15 percent of the general U.S. population has some form of it.
Brain imaging studies at UCSF have found that people with SPD show abnormal wiring in the nerve pathways that carry auditory, visual, and touch signals, including the connections between the left and right halves of the brain. These structural differences likely throw off the timing of sensory signals, making it hard for the brain to process input from multiple senses at once.
Types of Sensory Processing Disorder
SPD isn’t one single experience. It breaks into several patterns:
- Sensory over-responsivity: You’re unusually sensitive to sensory input. Sounds, textures, or lights that don’t bother most people feel overwhelming or painful.
- Sensory under-responsivity: You need more sensory input than usual before it registers. You might not notice temperature changes, pain, or someone calling your name.
- Sensory craving: You actively seek out intense sensory experiences, like spinning, crashing into things, or chewing on objects.
- Sensory discrimination disorder: You have trouble telling apart subtle differences in sensory input, like distinguishing similar sounds or textures.
- Postural disorder: You struggle to perceive your body’s position in space, which affects balance and coordination.
- Dyspraxia: A broad range of difficulties with planning and executing movements.
SPD frequently coexists with autism spectrum disorder, ADHD, OCD, bipolar disorder, and specific learning disorders. It is not currently listed as a standalone diagnosis in the DSM-5, which means some clinicians diagnose it under related conditions. Occupational therapists are typically the professionals who evaluate and treat it, using sensory integration therapy to help the brain learn to process input more effectively.
Symphysis Pubis Dysfunction
In pregnancy and postpartum contexts, SPD almost always refers to Symphysis Pubis Dysfunction. This is a condition where the joint at the front of your pelvis becomes too loose or moves unevenly, causing pain that can range from mild discomfort to severe, debilitating instability. Hormones released during pregnancy soften the ligaments around this joint to prepare for delivery, but in some women the loosening goes too far.
The hallmark symptom is pain at the front of the pelvis, but it often radiates to the lower back, groin, inner thighs, and perineum. Many women describe a sensation of the pelvis feeling “loose and wobbly,” sometimes with an audible clicking or grinding sound. The pain can show up as tingling, burning, stabbing, or a steady throb.
What makes symphysis pubis dysfunction so disruptive is how much it limits everyday movement. Getting out of bed, climbing stairs, standing on one leg to get dressed, getting in and out of a car, or simply walking can become painful or impossible. Even rolling over in bed or spreading your legs apart may trigger sharp pain. Some women also experience difficulty with urination or bowel movements, along with unexplained fatigue.
Management typically centers on physical therapy focused on pelvic stability, pelvic support belts that compress the joint, and movement modifications like keeping your knees together when turning in bed or getting out of a car. For most women, symptoms improve significantly after delivery as hormone levels return to normal, though recovery can take weeks to months.
Schizoid Personality Disorder
In psychiatric literature, SPD sometimes refers to Schizoid Personality Disorder, a condition defined by a pervasive pattern of social detachment and a narrow range of emotional expression. It begins in early adulthood and shows up across many areas of life.
A person with schizoid personality disorder typically shows at least four of these traits: little or no desire for close relationships (including with family), a strong preference for solitary activities, minimal interest in sexual experiences with others, enjoyment of very few activities, few or no close friends outside immediate relatives, indifference to both praise and criticism, and emotional flatness or detachment. The key distinction from simple introversion is that the pattern is rigid, lifelong, and causes meaningful impairment or distress.
Social Pragmatic Communication Disorder
SPCD, sometimes shortened to SPD, was introduced in the DSM-5 as a diagnosis for people who have persistent difficulty with the social use of language but don’t meet the full criteria for autism. The core problem is not grammar or vocabulary but the ability to use communication in socially appropriate ways.
This includes trouble adjusting how you speak depending on the situation (a classroom versus a playground, a child versus an adult), difficulty following conversational rules like taking turns or rephrasing when misunderstood, and problems understanding implied meaning, idioms, humor, sarcasm, or metaphors. All four of these areas must be affected for a diagnosis. SPCD is most often identified in children when social communication demands increase, such as in school settings.
How to Tell Which SPD Applies
Context usually makes it clear. If you encountered SPD in a parenting or occupational therapy setting, it almost certainly means Sensory Processing Disorder. If you’re pregnant or postpartum and reading about pelvic pain, it’s Symphysis Pubis Dysfunction. In psychiatric or personality disorder discussions, it points to Schizoid Personality Disorder. And in speech-language pathology or child development contexts, it likely refers to Social Pragmatic Communication Disorder.