Others view them as indecisive in their actions, self-absorbed, absent-minded and detached from their surroundings. Excessive daydreaming is often present. In cases with severe defects in the capacity to form social relationships, dating and marriage may not be possible. ICD-10 criteria
The Classification of Mental and Behavioural Disorders of ICD-10 lists SzPD under (F60.1).The general criteria of personality disorder (F60) should be met first. In addition, at least four of the following criteria must be present:

Few, if any, activities provide pleasure. Displays emotional coldness, detachment, or flattened affectivity. Limited capacity to express warm, tender feelings for others as well as anger. Appears indifferent to either praise or criticism from others. Little interest in having sexual experiences with another person (taking into account age). Almost always chooses solitary activities. Excessive preoccupation with fantasy and introspection. Neither desires, nor has, any close friends or confiding relationships (or only one). Marked insensitivity to prevailing social norms and conventions; if these are not followed, this is unintentional. Guntrip criteria
Ralph Klein, Clinical Director of the Masterson Institute, delineates the following nine characteristics of the schizoid personality as described by Harry Guntrip:: 13–23 
Introversion
Withdrawnness
Narcissism
Self-sufficiency
A sense of superiority
Loss of affect
Loneliness
Depersonalization
RegressionThe description of Guntrips nine characteristics should clarify some differences between the traditional DSM portrait of SzPD and the traditional informed object relations view. All nine characteristics are consistent. Most, if not all, must be present to diagnose a schizoid disorder. Millons subtypes
Theodore Millon restricted the term "schizoid" to those personalities who lack the capacity to form social relationships.
Retinal migraine involves migraine headaches accompanied by visual disturbances or even temporary blindness in one eye. Complications of migraine describe migraine headaches and/or auras that are unusually long or unusually frequent, or associated with a seizure or brain lesion. Probable migraine describes conditions that have some characteristics of migraines, but where there is not enough evidence to diagnose it as a migraine with certainty (in the presence of concurrent medication overuse). Chronic migraine is a complication of migraines, and is a headache that fulfills diagnostic criteria for migraine headache and occurs for a greater time interval. Specifically, greater or equal to 15 days/month for longer than 3 months. Abdominal migraine
The diagnosis of abdominal migraine is controversial. Some evidence indicates that recurrent episodes of abdominal pain in the absence of a headache may be a type of migraine or are at least a precursor to migraines. These episodes of pain may or may not follow a migraine-like prodrome and typically last minutes to hours. They often occur in those with either a personal or family history of typical migraine. Other syndromes that are believed to be precursors include cyclical vomiting syndrome and benign paroxysmal vertigo of childhood. Differential diagnosis
Other conditions that can cause similar symptoms to a migraine headache include temporal arteritis, cluster headaches, acute glaucoma, meningitis and subarachnoid hemorrhage.