Anorexia and lactose intolerance increase the risk of riboflavin deficiency. People with physically demanding lives, such as athletes and laborers, may require higher riboflavin intake. The conversion of riboflavin into FAD and FMN is impaired in people with hypothyroidism, adrenal insufficiency, and riboflavin transporter deficiency. Causes
Riboflavin deficiency is usually found together with other nutrient deficiencies, particularly of other water-soluble vitamins. A deficiency of riboflavin can be primary (i.e. caused by poor vitamin sources in the regular diet) or secondary, which may be a result of conditions that affect absorption in the intestine. Secondary deficiencies are typically caused by the body not being able to use the vitamin, or by an increased rate of excretion of the vitamin. Diet patterns that increase risk of deficiency include veganism and low-dairy vegetarianism. Diseases such as cancer, heart disease and diabetes may cause or exacerbate riboflavin deficiency.There are rare genetic defects that compromise riboflavin absorption, transport, metabolism or use by flavoproteins. One of these is riboflavin transporter deficiency, previously known as Brown-Vialetto-Van Laere syndrome. Variants of the genes SLC52A2 and SLC52A3 which code for transporter proteins RDVT2 and RDVT3, respectively, are defective. Infants and young children present with muscle weakness, cranial nerve deficits including hearing loss, sensory symptoms including sensory ataxia, feeding difficulties, and respiratory distress caused by a sensorimotor axonal neuropathy and cranial nerve pathology. When untreated, infants with riboflavin transporter deficiency  have labored breathing and are at risk of dying in the first decade of life.
Subtypes
Theodore Millon proposes two subtypes of schizotypal personality. Any individual with schizotypal personality disorder may exhibit either one of the following somewhat different subtypes (Note that Millon believes it is rare for a personality with one pure variant, but rather a mixture of one major variant with one or more secondary variants):

Treatment
Medication
STPD is rarely seen as the primary reason for treatment in a clinical setting, but it often occurs as a comorbid finding with other mental disorders. When patients with STPD are prescribed pharmaceuticals, they are usually prescribed neuroleptics of the sort used to treat schizophrenia; however, the use of neuroleptic drugs in the schizotypal population is in great doubt. While people with schizotypal personality disorder and other attenuated psychotic-spectrum disorders may have a good outcome with neuroleptics in the short term, long-term followup suggests significant impairment in daily functioning compared to schizotypal and even schizophrenic people without neuroleptic drug exposure. Antidepressants are also sometimes prescribed, whether for STPD proper or for comorbid anxiety and depression. Therapy
According to Theodore Millon, schizotypal personality disorder is one of the easiest personality disorders to identify but one of the most difficult to treat with psychotherapy. Persons with STPD usually consider themselves to be simply eccentric or nonconformist; the degree to which they consider their social nonconformity a problem differs from the degree to which it is considered a problem in psychiatry.