Female-to-male (FtM) treatments may cause or may worsen

  • Autism symptoms and impaired social functioning
  • Self-harm and suicide
  • Abnormal brain development in teens
  • Mood swings, delusions, impaired judgment, and psychiatric disorders such as schizophrenia
  • Attention deficit hyperactivity disorder (ADHD) symptoms
  • Verbal and IQ deficits, and memory and neurological disorders
  • Aggression and anti-social or criminal behaviors

Anabolic-androgenic steroid (testosterone drug) treatments raise testosterone to levels that may be 10 times higher than normal in female-to-male transsexuals (FtMs) and suppress estrogen and estrogen receptors. GnRHa “puberty-blocking” treatments also suppress estrogen. These treatments are not FDA-approved for gender transition purposes in biological females (see FDA 2015; Scutti 2017; Smith 2017).

Many different types of studies indicate that FtM treatments may have very dangerous effects. This page provides a simplified explanation. Readers who want more details from the studies should click here.

Above all, it’s important to remember that sex hormones can affect the entire brain.

Autism Symptoms & Impaired Social Functioning

Autism and many psychiatric disorders have already been associated with high testosterone, chronic testosterone conditions such as polycystic ovary syndrome (PCOS), and/or low estrogen. Click here for details. This suggests that high testosterone and/or low estrogen might help to cause autism and psychiatric disorders.

People with autism tend to have social functioning difficulties. Often they have problems recognizing and understanding other people’s expressions, body language, thoughts and feelings. Studies indicate that FtM drugs might make these problems worse.

A study showed that FtM treatments suppressed activity in brain areas that normally support social functioning, including the posterior superior temporal sulcus (PSTS), and altered brain activity in other areas. This might affect “emotional and social cognitive processes related to empathy and mentalizing,” the study showed:

“Long-term androgen administration reduced the pSTS activity in response to emotional stimuli as well as its response to social relation. More importantly, the functional connectivity among frontal, temporal and striatal regions was weakened while the connectivity among limbic regions was strengthened as the androgen level increased during hormone therapy…..[Androgen therapy] not only reduced the activity of a core neural hub but also markedly altered the organization of the brain network supporting emotional and social cognitive processes related to empathy and mentalizing” (Ye (2011).

A double-blind placebo-controlled study showed that a single dose of testosterone in healthy females “diminished their accuracy in inferring mental states” (Olsson 2016).

Another study showed that a single dose of testosterone in young women caused “significant impairment in their cognitive empathy,” particularly in young women who may have been exposed to excess testosterone prenatally (van Honk 2011).

A study also showed that a single dose of testosterone drugs changed young women’s brain activity during a test of ability to recognize other people’s facial expressions (Bos 2016). This test helps researchers to study social impairments in autism. The researchers said that their study revealed “a neural mechanism by which testosterone can impair emotion-recognition ability,” which may help to explain “the symptomatology of ASC [autism spectrum conditions.”

Self-Harm & Suicide

Females with autism and many psychiatric disorders already have very high rates of self-harm and suicidality. Autism and psychiatric conditions are common in females with gender dysphoria, so it is important to consider whether FtM treatments might increase self-harm and suicide risk. Researchers have already indicated that transition treatments do not decrease suicide risk.

Some studies have found high rates of suicidality in treated transsexuals (e.g., Dhejne 2011). Other studies have indicated that anabolic-androgenic drugs might cause self-harm and suicidality. Therefore, it’s possible that FtM treatments using such drugs help to cause self-harm and suicidality.

One study of suicides and other deaths in male steroid users found that users had “impulsive, disinhibited behavior characterized by violent rages, mood swings, and/or uncontrolled drug intake” and “an increased risk of violent death from impulsive, aggressive behavior, or depressive symptoms” (Thiblin 1999).

Another study found that girls who used steroids scored…higher on suicide risk…than boys who used steroids” (Miller 2002).

One study found that suicide attempts were seven times more common in a group of women with PCOS (a chronic excess testosterone condition) compared to other women (Måsson 2008). This suggests that high testosterone might increase suicidality in females.

A study found that high baseline levels of testosterone predicted future suicide attempts in females with bipolar disorder (Sher 2014).

Some researchers have suggested that high testosterone levels explain why men have much higher completed suicide rates than women (Rice 2015).

Abnormal Brain Development & Structural Changes

FtM treatments have already been shown to alter gray and white matter brain structures in adults (Burke 2018; Kranz 2018; Pol 2006; Rametti 2012; “Testosterone” 2015). Are those changes harmful, and could the treatments cause abnormal brain development in adolescents?

The National Institute on Drug Abuse (2018a) says:

“steroid use in teens is of concern, especially since the hormonal systems they interact with play a critical role in brain development during these years….[Medical research] suggests that pubertal steroid exposure could produce long-lasting structural changes in certain brain regions.”

Both testosterone and GnRHa (puberty-blocking) drugs may also cause abnormal brain development by blocking estrogen. Estrogen plays an important role in brain development. An animal study indicated that GnRHa treatments, which block estrogen, had especially strong effects on brain development in female animals (Nuruddin 2013).

Researchers worry about endocrine disruptors because those substances may alter the action of estrogen, with the “developing brain” being a “particularly sensitive target” (McCarthy 2008).

Testosterone and GnRHa drugs have not been carefully tested for adverse effects when used for gender transition purposes in females, so it’s hard to say how they might affect development. It’s worth considering that human females evolved to have normal estrogen levels together with normal female chromosomes (XX) during critical periods of brain development in adolescence and young adulthood. Imposing highly abnormal sex hormone levels on patients in those critical periods may not be that different from exposing fetuses to thalidomide during critical periods of development: By the time you know it’s a problem, it’s may be too late to fit it.

Mood Swings, Delusions, Impaired Judgment & Psychiatric Disorders

Both FtM testosterone and GnRHa drug treatments might cause mood swings and other problems. They might worsen psychiatric disorders such as schizophrenia, bipolar disorder or borderline personality disorder. They might cause patients to develop new psychiatric disorders.

An experimental study showed that GnRHa treatments in healthy women “increased depression symptoms” (Macoveanu 2016). Earlier studies indicated that “depressive mood symptoms increase in women treated with GnRH agonist therapy for endometriosis” (Warnock 1998).

A researcher said:

“Recent findings that GnRHas increase depression symptoms (Macoveanu et al., 2016) and slow reaction time (Stenbæk et al., 2016) in healthy women, and reduce long-term spatial memory in sheep (Hough et al., 2017) underline the importance of…research” on the drugs’ effects (Hayes 2016).

The FDA (2013) has said that anabolic-androgenic drugs can cause mood swings in girls and boys: “Mood swings are among the first side effects to show up, and steroid use may lead to mania or depression.”

The National Institute on Drug Abuse (2016) said that abuse of steroids could lead to “mental problems” such as paranoid  jealousy, extreme irritability, delusions, and impaired judgment.

The FDA (2017) said that “anabolic steroids have been associated with “serious reactions such as…altered mood, irritability, increased aggression, and depression.

High testosterone and polycystic ovary syndrome (POCS), a chronic excess testosterone condition, have been associated with depression, anxiety, bipolar disorder, schizophrenia, borderline personality disorder, and other psychiatric disorders in many different studies. Click here for details.

Low estrogen, which could result from GnRHa drugs or high-testosterone drug treatments, has also been associated with depression and psychiatric disorders, including posttraumatic stress disorder (PTSD) and possibly schizophrenia. Click here for details.

These studies suggest that FtM treatments that raise testosterone and suppress estrogen might induce mood swings and psychiatric disorders.

A study has also shown that FtM testosterone alters brain areas responsible for self-related thinking: “testosterone treatment resulted in functional and structural changes in self-referential and own body perception areas” of the brain (Burke 2018). This might produce adverse effects, especially if the drug treatments also induce mood swings, impaired judgment, and other problems.

Attention Deficit Hyperactivity Disorder (ADHD) Symptoms

A study found that “ADHD symptoms were most pronounced” in women “when estrogen was low” (Roberts 2016).

The National Institute on Drug Abuse (2018a) said that anabolic-androgenic steroids may cause ADHD-like symptoms:

“Teens who use anabolic steroids may also be at increased risk for some cognitive side effects compared with adults. For example, males who begin using anabolic steroids during the teen years show increased impulsivity and decreased attention, compared to men who began using steroids in their adult years. In adolescent rats, anabolic steroid exposure is associated with…hyperactivity, anxiety, and increased sympathetic autonomic modulation (e.g., fight or flight response) during adulthood, even when steroid use was discontinued during adolescence.”

Verbal Deficits, IQ, Memory, & Neurological Disorders

One of the earliest FtM studies showed: “The administration of androgens to [female-to-male transsexuals]…had a deteriorating effect on verbal fluency tasks” (van Goozen 1995).

A more recent study showed that FtM treatments reduced “the volume of grey matter…in two specific regions of the brain, the Broca’s and Wernicke’s areas, which are mainly responsible for language processing” ECNP (2015).

A study found that higher testosterone levels were correlated with poorer verbal memory in women with chronic schizophrenia (Worsley 2014).

Estrogen-suppressing drugs might lower intelligence scores. A study found that girls treated with GnRHa drugs for “precocious puberty” had “fairly substantial difference found in IQ scores” compared to other girls (Hayes 2017).

A study found that estrogen supplements improved verbal memory in female athletes with estrogen deficiency (Baskaran (2017).

A study indicated that anabolic-androgenic steroids might cause deficits in “everyday memory” (Heffernan (2015).

Evidence suggests that “androgen abusers may be at increased risk for dementia” (Kanayama 2018; Pope 2017).

Studies indicate that steroids may cause effects similar to repetitive concussion or other problems (Kaufman 2016; Namjoshi 2016).

Aggression & Anti-Social or Criminal Behavior

One of the earliest studies of FtM treatments showed that the drugs clearly increased aggression proneness in transsexuals:

“In a group of 35 female-to-male transsexuals…a large battery of tests on aggression, sexual motivation and cognitive functioning was administered twice: shortly before and three months after the start of cross-sex hormone treatment. The administration of androgens to females was clearly associated with an increase in aggression proneness”(van Goozen 1995).

FtM treatments may induce aggressive, anti-social, and even criminal behaviors. A follow-up study of treated transsexuals showed: “Female-to-males, but not male-to-females, had a higher risk for criminal convictions than their respective birth sex controls” (Dhejne (2011).

Testosterone drugs have been shown to activate aggression-related brain circuits in healthy females :

“These data demonstrate that testosterone enhances responsiveness in neural circuits of social aggression” in females (Hermans 2008).

Testosterone drugs have been shown to “shift the balance between sensitivity for punishment and reward in healthy young women” (van Honk (2004). The researchers speculated that this might help to explain a connection between high testosterone and psychopathy. “Testosterone was positively related to psychopathy” in women and men in a study (Welker 2014).

In addition, testosterone drugs have been shown to reduce conscious detection of facial expressions that normally serve the purpose of “social correction” (van Honk 2007). Testosterone has also been shown to modulate moral judgment in females (Chen 2016). These effects altogether might increase anti-social or criminal behaviors in FtM patients.

A study indicated that anabolic-androgenic drug use “is highly overrepresented in women who commit crimes” (Lundhold 2010).

Higher levels of testosterone were associated with “criminal violence and aggressive dominance in prison among women” (Dabbs 1997).

Researchers found that “female hyperandrogenism in adulthood, but not prenatal hyperandrogenism, is associated with risk for criminal behavior” (Ohlsson Gotby 2015).

The FDA (2013) has said that anabolic-androgenic steroids may cause aggressive behavior in girls and boys.

The FDA (2017) said that “anabolic steroids have been associated with…altered mood, irritability, [and] increased aggression.” It advised anyone using body building products that may “contain steroids or steroid-like substances…[to] stop taking them immediately.”

The National Institute on Drug Abuse (2017) said:

“Anabolic steroids affect a part of the brain called the limbic system, which controls mood. Long-term steroid abuse can lead to aggressive behavior and extreme mood swings. This is sometimes referred to as ‘roid rage.”

A 2008 study found that “testosterone enhances responsiveness to social threat in the neural circuitry of social aggression” (Hermans (2008).

A 2018 study found that “women react more aggressively in response to provocation when their testosterone level is high than when their testosterone is low” (Probst 2018).

Female partners of FtMs may be at-risk from violence committed by FtMs. A study of male anabolic-androgenic steroid (AAS) users said that AAS users:

“reported significantly more fights, verbal aggression, and violence toward their significant others when using AAS than when not using AAS…These findings support the anecdotal evidence that wives and girlfriends of AAS users may be at risk of serious injury from users while they are on-drug” (Choi 2011).

A study found that anti-social behaviors were significantly higher” among males who used AAS drugs, compared to other males (Hallgren 2015).

A study suggested “an association between the use of AAS and criminality, especially with regard to crimes of violence and weapon offences” (Skårber (2010).

Animal studies indicate that increased aggression may continue even after AAS drug use stops, if AAS exposure has taken place during adolescence. This may be due to the drugs’ effects on development of androgen receptors in the brain (National Institute on Drug Abuse (2018a). Continued exposure to high levels of testosterone may affect the development of androgen receptors in the brains of females, including FtM patients (see Rametti 2012).

Testosterone drugs have been shown to “functionally disconnect” the amygdala from the orbitofrontal cortex in healthy women (van Wingen 2010). This also seems to occur in adolescents with high levels of testosterone (Spielberg 2015). A study of brain activity in AAS drug users found “reduced functional connectivity between key nodes involved in emotional and cognitive regulation” (Westlye 2017).

These studies provide support for the idea that testosterone drugs may cause changes in brain activity that could lead FtMs to act in impulsive, violent, anti-social, and criminal ways.